Mesenchymal stem cell therapy for premature ovarian insufficiency: progress and challenges.

Ovarian cancer, although accounting for only about 3% of female malignancies, imposes a disproportionate mortality burden. GLOBOCAN-2022 recorded 324,398 new cases and 206,839 deaths worldwide, and demographic modelling predicts that annual incidence will exceed half a million by 2050, with the greatest absolute growth in Asia and the steepest percentage rise in sub-Saharan Africa [ 38 ]. In the United States the lifes time risk of developing the disease is roughly 1 : 91 (death 1 : 143); half of diagnoses occur after 63 years of age, and non-Hispanic White women have the highest incidence, whereas Black women experience poorer stage-adjusted survival [ 39 ]. In China, the burden of ovarian cancer has markedly increased over the past three decades and is projected to rise at a pace exceeding the global average by 2030. Despite this growing incidence, the five-year overall survival rate remains stagnant at approximately 40%, with limited progress in early detection and standardized care [ 40 ]. Forecasting analysis predicts that both incidence and mortality will continue to rise over the next three decades, reaching their peaks by 2049, particularly in older age group [ 41 ]. These findings emphasize the urgent need for improved prevention strategies, early detection programs, and age-targeted interventions. Histologically, more than 90% of tumours are epithelial, of which high-grade serous carcinoma (HGSC) dominates and alone explains about 70% of deaths [ 42 ]. HGSC is characterised by near-universal TP53 mutation, homologous-recombination deficiency driven by germline or somatic BRCA1/2 loss, and frequent CCNE1 amplification [ 43 ]; low-grade serous and mucinous variants instead harbour MAPK-pathway lesions such as KRAS or BRAF V600E [ 44 , 45 ]. The International Federation of Gynecology and Obstetrics (FIGO) staging remains the single most important prognostic factor: five-year relative survival approaches 92% when disease is confined to the ovaries (stage I) but falls to ≈ 32% with distant metastasis (stage IV) [ 46 , 47 ]. Unfortunately, the absence of population-level screening and the protean nature of early symptoms mean that fewer than one quarter of patients are diagnosed at a surgically curable stage. Primary treatment is surgical. In apparent early-stage disease, comprehensive staging with unilateral salpingo-oophorectomy can conserve fertility; in advanced disease the aim is complete macroscopic cytoreduction (residual nodules < 1 cm) followed by platinum–taxane chemotherapy [ 48 ]. Intraperitoneal or hyperthermic intraperitoneal chemotherapy offers pharmacokinetic advantages in selected fit patients [ 49 – 51 ], while bevacizumab-based anti-angiogenic therapy and maintenance poly-(ADP-ribose)-polymerase inhibition (olaparib, niraparib or rucaparib) have become standard for tumours with homologous-recombination deficiency [ 52 , 53 ]. For platinum-resistant relapse, antibody–drug conjugates are redefining the landscape: in March 2024 the U.S. FDA granted full approval to mirvetuximab soravtansine-gynx (Elahere ® ) for folate-receptor-α-positive disease after one to three prior lines, significantly prolonging overall and progression-free survival compared with physician-choice chemotherapy [ 54 , 55 ]. Radiotherapy retains only a palliative role because of relative radioresistance and dose-limiting toxicity to adjacent bowel [ 56 ]. Risk-reducing salpingo-oophorectomy is advised for BRCA carriers once child-bearing is complete, lowering lifetime incidence by up to 90% but inducing surgical menopause [ 57 , 58 ]. Cytoreductive removal is also indicated whenever tumour bulk or symptoms threaten organ function; conversely, interval debulking is avoided when imaging suggests no chance of achieving R0 resection [ 59 , 60 ]. Interest is growing in mesenchymal-stem-cell-based regenerative therapy to restore endocrine function after gonadotoxic treatment [ 60 , 61 ]. Pre-clinical models show that intra-ovarian injection of bone- or menstrual-derived MSCs can revive folliculogenesis via paracrine exosomes [ 62 , 63 ]. Although devised to eradicate extra-pelvic tumours, many cytotoxic regimens inadvertently target the ovary—a tissue whose finite follicle pool cannot be renewed [ 64 – 66 ]. Breast cancer, lymphomas, leukaemias and bone-marrow–ablative conditioning for transplantation commonly employ alkylating agents (e.g. cyclophosphamide, busulfan), platinum salts and ionising radiation, all of which converge on several interconnected pathogenic pathways in the ovary [ 67 – 70 ]. Most cytotoxics generate excess reactive oxygen species (ROS) either directly (radiolysis of water, redox cycling of platinum) or indirectly by impairing antioxidant enzymes [ 71 , 72 ]. Accumulated ROS oxidise membrane lipids, denature mitochondrial proteins and introduce oxidative DNA lesions such as 8-oxo-dG [ 73 , 74 ]. The ovarian cortex, rich in polyunsaturated fatty acids yet relatively poor in catalase and superoxide dismutase, is therefore uniquely susceptible [ 75 , 76 ]. ROS overload also activates p38-MAPK and JNK cascades, amplifying stress signalling in granulosa and thecal cells [ 77 ] ( Fig. 1 ) . Classical apoptosis remains the dominant mode of follicular loss: double-strand breaks trigger ATM/ATR-p53 signalling, up-regulating BAX/BAK and prompting mitochondrial outer-membrane permeabilisation with cytochrome-c release [ 78 – 81 ]. Caspase-3 activation dismantles granulosa cells, and denuded oocytes undergo secondary atresia [ 82 , 83 ]. Emerging evidence implicates programmed necrosis (necroptosis), pyroptosis (gasdermin-D pore formation) and ferroptosis (lipid peroxidation driven by iron accumulation) as additional contributors, implying multiple, drug-specific death executors [ 72 , 79 , 84 – 86 ]. Chemotherapeutic ROS and calcium overload depolarise the mitochondrial inner membrane, exhaust ATP reserves and foster release of pro-apoptotic factors [ 87 – 89 ]. Damaged mitochondria also emit damage-associated molecular patterns (DAMPs) that intensify local inflammation and contribute to stromal fibrosis, an irreversible component of ovarian ageing [ 90 – 92 ]. Beyond the well-recognised gonadotoxicity of cancer therapy, a spectrum of non-cancerous disorders—including genetic, autoimmune diseases and environmental factors—can compromise ovarian integrity and precipitate POI ( Fig. 1 ) . While approximately 75% of cases remain idiopathic, accumulating evidence from clinical and molecular studies has elucidated several key non-iatrogenic factors that contribute to spontaneous POI onset, encompassing genetic, autoimmune, infectious, environmental, and metabolic domains [ 93 ]. Genetic and Chromosomal Abnormalities represent the most well-characterized category. Turner syndrome (monosomy X) is observed in 4–5% of POI cases, manifesting with accelerated follicular atresia due to haploinsufficiency of X-linked genes such as BMP15 [ 94 ]. Fragile X premutation carriers (55–200 CGG repeats) are also at elevated risk, with studies reporting premature menopause in up to 28% of women harboring such alleles [ 95 ]. In addition, single-gene defects in STAG3 and BRCA2 have been implicated in hereditary POI syndromes, highlighting the critical role of meiotic integrity and oocyte maintenance genes [ 96 , 97 ]. Autoimmune Mechanisms are another significant contributor, often linked with polyglandular autoimmune syndromes [ 98 , 99 ]. Circulating antibodies targeting steroid-producing ovarian cells and lymphocytic infiltration of the theca interna have been observed in patients with concurrent Addison’s disease or type I diabetes. Environmental and Lifestyle Factors have gained increasing attention. Cigarette smoke, rich in polycyclic aromatic hydrocarbons (PAHs), exerts direct ovotoxic effects via AHR-mediated Bax activation and apoptosis induction in granulosa cells [ 100 , 101 ]. Epidemiological studies consistently link smoking with reduced antral follicle count, elevated serum FSH, and earlier menopause onset. Furthermore, endocrine-disrupting chemicals (EDCs) such as bisphenol A (BPA), phthalates, and persistent organic pollutants may disrupt folliculogenesis and steroidogenesis, leading to premature follicle depletion and compromised ovarian reserve [ 102 – 104 ]. Mitochondrial dysfunction in POI is characterized by a reduction in mitochondrial DNA (mtDNA) copy number, increased oxidative damage, and pathogenic mutations that compromise the oxidative phosphorylation (OXPHOS) system [ 105 ]. Mitochondria act dually as both generators and targets of ROS, with OXPHOS responsible for more than 95% of intracellular ROS production. Due to aging-associated electron leakage from the respiratory chain and elevated ROS levels, mtDNA is particularly vulnerable to oxidative insult. The progressive accumulation of oxidative stress–induced mtDNA damage can exceed a functional threshold, resulting in respiratory chain defects and global mitochondrial impairment. These intrinsic or acquired mitochondrial abnormalities contribute to granulosa cell and oocyte apoptosis, accelerate follicular atresia, and ultimately lead to diminished ovarian reserve. Taken together, these findings underscore the complex and multifaceted nature of primary POI. Identification of causative factors is essential not only for clinical management and genetic counseling, but also for implementing fertility preservation strategies in high-risk individuals. Fig. 1 Schematic illustration of ovarian collateral circulation damage induced by non-ovarian cancer radiotherapy, chemotherapy and ovarian injury mechanisms under non-malignant disease conditions Schematic illustration of ovarian collateral circulation damage induced by non-ovarian cancer radiotherapy, chemotherapy and ovarian injury mechanisms under non-malignant disease conditions Despite the heterogeneity of insults—chemotherapy, infection, autoimmunity or aging—ovarian failure frequently converges on a restricted set of molecular checkpoints that maintain follicle survival and endocrine competence. Foremost among these is the DNA-damage response (DDR). Germ-line or somatic defects in BRCA1/2 , ATM or the oocyte-specific guardian TP63 accelerate follicular attrition by lowering the apoptotic-activation threshold after genotoxic stress [ 81 , 106 , 107 ]. Similarly, dysregulation of the PI3K–Akt–FOXO3 axis drives premature awakening of dormant primordial follicles: activating mutations in PIK3CA or loss of PTEN propel unrestrained follicle recruitment, exhausting the reserve [ 108 – 110 ]. Parallel crosstalk with the mTOR and Hippo–YAP/TAZ networks modulate granulosa-cell proliferation and stromal fibrosis; aberrant YAP phosphorylation or mTOR hyper-activation has been documented in both chemotherapy-injured and autoimmune ovaries [ 111 , 112 ]. At the metabolic interface, oxidative stress impairs the Nrf2 antioxidant defense system and compromises mitochondrial membrane integrity [ 113 , 114 ], while emerging non-apoptotic cell death pathways—such as ferroptosis (GPX4/ACSL4) and necroptosis (RIPK1/3–MLKL)—drive follicular demise in toxin-exposed or inflamed ovaries [ 79 , 115 ]. Notably, although pyroptosis mediated by gasdermin-D is also classified within this emerging cell-death paradigm, it is more commonly investigated as a therapeutic target in ovarian cancer rather than a mechanistic driver of ovarian injury [ 116 ]. Layered onto these genomic and signalling defects are epigenetic derangements that lock the ovary into a pathologic state. Genome-wide and locus-specific DNA hyper-methylation of anti-apoptotic genes (e.g. BCL2 , SIRT1 ), mediated by DNMT3A/B over-expression, accompanies doxorubicin- and cyclophosphamide-induced POI [ 117 ]. On the other hand, in ovarian cancer, the BRCA1 gene is completely or partially inactivated through hypermethylation of its promoter region [ 118 ]. Repressive histone marks (H3K27me3 via EZH2) accumulate on follicle-activating loci, whereas loss of acetylation by over-active HDACs curtails transcription of antioxidants and hormone-synthesis enzymes [ 119 , 120 ]. RNA modifications add a third tier: aberrant m6A deposition by METTL3/14 or its removal by FTO perturbs stability of mRNAs encoding DDR modulators, such as RAD51 and CHEK1 [ 121 ]. Post-translationally, hyper-phosphorylation and ubiquitin-mediated degradation of FOXO3a hasten follicle activation [ 122 ]. MSCs are uniquely positioned to recalibrate these molecular derangements through both cell-extrinsic and cell-intrinsic mechanisms. Paracrine factors such as IGF-1, HGF and VEGF directly activate PI3K–Akt and inhibit intrinsic apoptosis [ 27 ], while exosomal miR-21, miR-144-3p and miR-126 down-regulate PTEN , MAP3K9 and other DDR amplifiers, reinstating controlled follicle activation and reducing oxidative phosphorylation overload [ 21 , 25 , 62 ]. Notably, MSC upregulated the activity of superoxide dismutase (SOD) and restore the Nrf2 redox shield, curtailing ferroptotic lipid peroxidation and preserving mitochondrial membrane potential [ 123 ]. Experimental delivery of FTO-overexpressing MSCs alleviated m6A hyper-methylation of YAP1 transcripts, reactivating Hippo signalling and reducing cisplatin cytotoxicity in granulosa cells [ 124 ] ( Fig. 2 ) . Fig. 2 MSCs enhance ovarian regeneration via paracrine/exosomal mechanisms and pathway restoration MSCs enhance ovarian regeneration via paracrine/exosomal mechanisms and pathway restoration In summary, diverse ovarian insults—including chemotoxic, infectious, autoimmune, and age-related stressors—converge upon a finite set of molecular vulnerabilities involving DNA damage response, follicle activation pathways, metabolic homeostasis, and epigenetic regulation. These disruptions accelerate follicular depletion and compromise endocrine output. Mesenchymal stem cells (MSCs) offer a multifaceted reparative strategy by restoring key signaling pathways, attenuating oxidative and ferroptotic stress, and reversing detrimental epigenetic modifications. Through paracrine signaling and exosomal cargo, MSCs can re-establish homeostatic gene expression and enhance follicular resilience, thereby holding promise for therapeutic rescue of ovarian function.

MSC therapy has moved from an experimental curiosity to a credible onco-fertility strategy over the past 15 years. Rodent models consistently demonstrate that bone-marrow, adipose, umbilical-cord, placental and menstrual-blood MSCs can restore oestrous cycling, replenish multi-stage follicle pools and even support live births after exposure to alkylating agents, platinum compounds or radiation. The weight of these pre-clinical data, together with congruent findings in large animals and early human studies, underpins growing optimism that cellular regeneration can close the gap left by cryopreservation, GnRHa co-therapy and hormone replacement, all of which safeguard parenthood options but do little to repair endogenous ovarian function [ 169 ]. A recurring mechanistic theme across sources is that MSCs work less as building blocks and more as biochemical “conductors”. Their secretome is rich in IGF-1, HGF and VEGF, which shield granulosa cells from apoptosis and promote angiogenesis, while exosomal miRNAs such as miR-21, miR-126-3p and clusterin-associated cargos converge on PI3K–Akt to reboot survival and mitochondrial resilience. This paracrine dominance is encouraging because it implies that durable benefit may be achieved without long-term engraftment, potentially reducing oncogenic risk. Nevertheless, source-specific differences in secretory profile, immunomodulation and in-vivo persistence persist. Perinatal MSCs exhibit powerful anti-inflammatory effects but shorter tissue residence than adult counterparts, whereas adipose-derived MSCs are easily harvested yet show variable angiogenic output—variability that still lacks a molecular explanation. Comparative studies emphasise that “one source does not fit all”. For instance, mild hypomethylation of bone-marrow MSCs amplifies their secretome and outperforms naïve cells in cisplatin models, while coupling the same cells with neonatal ovarian aggregates yields an “artificial ovary” capable of folliculogenesis without uncontrolled proliferation. Adipose MSCs, by contrast, double as tumour-homing vectors that can be armed with TRAIL or enzyme-prodrug systems for ovarian-cancer cytoreduction, illustrating the spectrum from fertility restoration to adjunct oncologic therapy [ 174 ]. Such versatility is attractive, yet it magnifies the need for rigorous potency assays so that dose, route and timing can be personalised rather than empirically chosen. Translational momentum is no longer confined to rodents. In cynomolgus and rhesus monkeys, single intra-ovarian injections of embryonic-derived or umbilical cord–derived MSCs reduced fibrosis, revived steroidogenesis, and, in one case, culminated in the birth of a healthy infant [ 192 , 193 ]. Although still limited, human data mirror these trends. Autologous menstrual-blood MSCs have restored menses and increased oestradiol levels with minimal adverse events observed over a three-year follow-up period. Yet the evidence is heterogenous: most trials are single-arm, lack placebo controls and use disparate endocrine endpoints, making efficacy comparisons precarious [ 195 , 196 ]. Three hurdles temper the excitement. First, homing is woefully inefficient—often < 1% of cells reach the ovary after systemic infusion—spurring work on CXCR4 over-expression, hypoxic pre-conditioning and decellularised scaffolds, but none has yet passed clinical muster [ 30 ]. Second, manufacturing is fragmented: passage number, oxygen tension and xeno-free media vary widely between laboratories, clouding reproducibility and complicating regulatory review. Third, potency assays rarely extend beyond surface immunophenotyping; introducing harmonised release criteria linked to paracrine bioactivity is essential if multicentre trials are to generate pooled datasets. Safety remains the elephant in the room. Although most animal studies report no malignancies, co-injection of umbilical-cord MSCs with SK-OV-3 cells enlarged tumours fourfold and seeded liver metastases, while carcinoma-associated MSCs facilitate “metastatic escort” via WT1/EZH2-driven epithelial transition [ 198 , 199 ]. Conversely, passage-10 adipose or cord MSCs injected into cancer-free ovaries showed no tumours at 16 weeks—but this window is short relative to human relapse timelines and may underestimate late events [ 200 ]. Vigilant donor screening, suicide-gene safeguards and exclusion of patients with residual disease should therefore accompany early-phase trials. Recognising both the promise and the pitfalls, many groups are pivoting toward cell-free products. Exosome-loaded GelMA microspheres releasing miR-21 for seven days rescued fertility in cyclophosphamide mice, while hyaluronic-acid carriers of LPS-primed exosomes boosted antral follicle counts without introducing living cells [ 202 , 203 ]. Such acellular platforms ease storage, reduce immunogenicity and sidestep transformation risk, but they narrow the secretome and raise new questions about biodistribution and batch potency. Parallel advances in mitochondrial transfer and biomimetic “artificial ovaries” further illustrate that the field is expanding along multiple technological axes; coordinated benchmarking will be critical to avoid a fragmented evidence base. Looking ahead, four priorities stand out. First, integrate pharmacokinetic imaging to correlate cell or vesicle retention with endocrine and fertility outcomes, thereby validating homing-enhancement strategies. Second, embed standardised panels—AMH, inhibin B, antral follicle count and live-birth—as core endpoints across trials to facilitate meta-analysis. Third, align good-manufacturing-practice pipelines around critical quality attributes such as miRNA cargo and angiogenic potency, ensuring lot-to-lot consistency. Finally, adopt adaptive trial designs that stratify patients by age, baseline reserve and oncologic status; the diminished efficacy seen in women over forty suggests that the ovarian niche has an age ceiling that may necessitate combination with tissue engineering or gene editing. The review’s own roadmap—calling for harmonised endpoints, GMP cell or exosome production and multicentre randomisation—provides a pragmatic template. In sum, MSC-based ovarian regeneration sits at an inflection point: pre-clinical depth and early human feasibility have built a strong biological foundation, yet translation demands equally rigorous attention to manufacturing, safety and trial architecture. If these gaps are bridged, MSCs could transform survivorship by allowing young cancer patients to confront their disease without forfeiting reproductive autonomy.

Research exploring MSCs as a remedy for POI took shape in 2008, when Fu et al. showed that direct intra-ovarian transplantation of bone-marrow-derived MSCs restored estrous cycling, revived estrogen secretion and cut granulosa-cell apoptosis in cyclophosphamide-injured rats, effects linked to paracrine VEGF, HGF and IGF-1 release [ 167 ]. Five years later, Abd-Allah’s rabbit study confirmed that intravenously infused MSCs homed to damaged ovaries, differentiated into stromal-like cells, boosted VEGF and normalized the FSH/E2 ratio, rebuilding follicular architecture and hinting at systemic delivery as a feasible route [ 168 ]. Over the ensuing decade, attention shifted from proof-of-concept to mechanism and optimization. Work on exosomes and conditioned medium revealed that MSC-derived miR-17-5p, miR-126-3p and miR-664-5p can dampen oxidative stress, suppress caspase-3 and reactivate PI3K/AKT signalling in chemotherapy-damaged granulosa cells, suggesting cell-free products as next-generation therapeutics; parallel experiments broadened sources to umbilical cord, adipose tissue and menstrual blood and explored minimally invasive intra-arterial or hydrogel-based delivery. A 2023 systematic review collating 112 pre-clinical studies reports consistent gains in follicle number, hormone milieu and, in rodents, live-birth rates; encouragingly, initial human case series now describe resumed menses and successful oocyte retrieval after autologous MSC grafting [ 169 ]. Collectively, fifteen years of incremental advances have propelled MSC therapy for POI from experimental curiosity toward translational reality, though standardized protocols and long-term safety monitoring remain essential. Table 1 Comparative therapeutic potential of mesenchymal stem cells (MSCs) from different sources Source Advantage Core Mechanisms Clinical Progress Bone Marrow MSC​ Most extensively studied; Amenable to engineering (e.g., artificial ovary constructs) Paracrine secretion of VEGF/HGF; Enhanced secretory activity through hypomethylation Restoration of estrous cycle and live births in animal models Adipose MSC Easily accessible; Potential tumor-targeting capability Inhibition of PI3K/AKT overactivation; Anti-tumor effects via TRAIL delivery Extended reproductive lifespan in chemotherapeutic mouse models Umbilical Cord MSC Low immunogenicity; Exosome-rich Angiogenesis promotion via miR-126-3p-PIK3R2; Reversal of ferroptosis Restoration of hormone levels in rat premature ovarian insufficiency (POI) models Placental MSC Strong pro-angiogenic potential Activation of VEGF/PDGF pathways; Enhanced vascular stability via PRL-1 overexpression Recovery of E2 levels in ovariectomized rat models Menstrual Blood MSC High safety profile for autologous transplantation Upregulation of Nrf2 antioxidant pathway; Improved oocyte quality via mitochondrial transfer Clinical Phase I/II : Menstrual restoration in POF patients (30% live birth rate) Follicle/Stem Cell Derivatives Novel sources (hair follicle, neural crest) Anti-ferroptosis via Keap1-NRF2-HO-1 pathway Follicle count recovery in mouse models Comparative therapeutic potential of mesenchymal stem cells (MSCs) from different sources Bone marrow–derived mesenchymal stem cells (BM-MSCs) have emerged as one of the most extensively studied candidates for regenerative therapy in preclinical models aimed at rescuing fertility after gonadotoxic cancer treatment. As previously mentioned, proof-of-concept came in 2008, when intra-ovarian BM-MSC transplantation in cyclophosphamide-injured rats restored estrous cycling, increased estrogen production and rebuilt follicular architecture, establishing that paracrine support from these cells can revive a depleted ovary [ 167 ]. Subsequent work has focused on enhancing cell survival and potency against chemotherapy. A pivotal 2018 study showed that a brief 42 °C, 1 h heat-shock pre-conditioning lowered MSC apoptosis, boosted their proliferation and, once injected into cyclophosphamide-treated ovaries, more effectively reduced granulosa-cell death, normalized FSH/E₂ ratios and expanded multi-stage follicle pools [ 170 ]. Radiotherapy poses additional oxidative and DNA-damaging stressors, yet BM-MSCs again proved resilient. Intravenous delivery of 2 × 10⁶ cells one week after a 3.2 Gy whole-body γ-irradiation successfully homed to rat ovaries, restored estradiol levels, and rescued fertility. Mechanistically, the treatment simultaneously activated Wnt/β-catenin and Hippo pathways while suppressing TGF-β signalling via miRNA cargo, thereby coordinating anti-apoptotic and pro-proliferative gene programs [ 22 ]. More recently, researchers have exploited epigenetic priming. Mild global hypomethylation of BM-MSCs with 0.5 µM 5-Aza-dC preserved stemness markers, enriched their secretome and, when either modified cells or conditioned medium were administered to cisplatin-induced premature ovarian failure mice, they outperformed unmodified counterparts in restoring AMH, E₂ and FSH levels and in rebuilding healthy primordial-to-antral follicle populations [ 171 ]. Finally, integrating BM-MSCs into a single-cell “artificial ovary” has pushed the field toward tissue engineering. When neonatal mouse ovarian cells were re-aggregated with BM-MSCs (1:1) and grafted under the kidney capsule, oocytes survived, normal folliculogenesis proceeded, and the MSCs localized around developing follicles—guiding theca-layer differentiation without uncontrolled proliferation [ 19 ]. Collectively, these studies sketch a decade-long trajectory from basic cell replacement to sophisticated pre-conditioning, pathway-targeting and bio-scaffold strategies. They highlight BM-MSCs’ dual capacity to blunt chemotherapy- or radiotherapy-triggered apoptosis and to re-ignite follicle growth, laying a translational foundation for clinically standardized, precision-engineered stem-cell therapies for premature ovarian insufficiency after cancer treatment. Adipose-derived mesenchymal stem cells (AD-MSCs) combine easy harvest with strong paracrine and tumour-homing abilities, making them attractive both for ovarian cancer therapy and for reversing chemotherapy-induced POI. In the first rodent proof-of-concept, local grafting of AD-MSCs into cyclophosphamide-injured ovaries restored follicle and corpus-luteum counts by secreting high levels of VEGF, IGF-1 and HGF, while male-cell tracking revealed the transplanted cells lodge mainly in the thecal layer rather than the germ line [ 172 , 173 ]. Capitalising on their tumour tropism, Yin et al. magnetically loaded AD-MSCs with a heat-shock–driven TRAIL plasmid. Once the engineered cells accumulated in ovarian xenografts, a brief alternating magnetic field raised their temperature to approximately 41 °C, activated TRAIL, and triggered significant apoptosis of cancer cells both in vitro and in vivo, without harming normal tissue [ 174 ]. Malekshah and colleagues then armed AD-MSCs with secreted carboxylesterase-2, allowing systemic irinotecan to be converted into its potent metabolite SN-38 directly inside intraperitoneal metastases; this enzyme–prodrug strategy eradicated patient-derived tumours in mice and markedly prolonged survival compared with standard cisplatin/paclitaxel [ 175 ]. Parallel efforts have refined AD-MSC therapy for POI. In CD-1 mice given mild or heavy busulfan/cyclophosphamide, a single tail-vein infusion of 10 6 human ASCs preserved ovarian weight, vasculature and multi-stage follicle pools, rescued blastocyst competence and, critically, extended reproductive lifespan and litter production, even in the severe model [ 176 ]. More mechanistic work shows that intravenously delivered AD-MSCs blunt granulosa-cell apoptosis, curtail senescence markers (SA-β-gal) and normalise FSH and AMH by suppressing over-active PI3K/AKT/mTOR signalling in acute and chronic cyclophosphamide rat models, highlighting a conserved anti-ageing pathway [ 177 ]. Collectively, a decade of incremental advances positions AD-MSCs as dual-purpose agents: they can be bio-engineered into smart “living missiles” that deliver cytotoxic payloads with spatiotemporal precision against metastatic ovarian cancer, and, when used in their naïve or minimally modified forms, can rejuvenate the chemotherapy-damaged ovary, restore endocrine balance and prolong fertility—laying the groundwork for personalised, fertility-sparing cancer care. Placenta-derived mesenchymal stem cells (PD-MSCs) have gained momentum as a regenerative candidate for restoring compromised ovarian function because they are abundant, immunologically tolerant and rich in pro-angiogenic secretions. In aged rats, repeated tail-vein infusion of human PD-MSCs accelerated primordial-to-antral follicle transition and boosted estradiol and AMH secretion by down-regulating miR-145-5p, thereby unleashing BMP-SMAD signalling and expanding the follicular pool [ 178 ]. Complementary work in ovariectomised models shows that PD-MSCs remodel the ovarian microenvironment: they activate the PI3K/FOXO3 axis, re-establish the balance between growth and apoptosis in oocytes, and restore hormone profiles to near-physiological ranges [ 179 ]. A central driver of these benefits is vascular repair. Intravenous delivery of 5 × 10 5 PD-MSCs reinstated VEGF/VEGFR-2 signalling, enlarged capillary networks around growing follicles and curtailed atresia, culminating in higher follicle numbers and serum estradiol in ovariectomised rats [ 180 ]. Engineering the cells to over-express phosphatase-regenerating-liver-1 further amplified platelet-derived growth factor cascades, thickened vessel walls and enhanced pericyte recruitment, highlighting how targeted gene editing can potentiate PD-MSC-mediated angiogenesis [ 181 ]. Beyond vasculature, PD-MSCs mitigate oxidative stress. A dose-ranging study demonstrated that even low-dose transplantation (1 × 10 5 cells) lowered systemic glutathione oxidation, normalized FSH/estradiol ratios and promoted folliculogenesis; increasing the dose did not yield proportional gains, underscoring the importance of optimisation rather than maximisation [ 182 ]. Secretome engineering is an emerging frontier: PD-MSCs primed to secrete high hepatocyte-growth-factor engage Wnt/β-catenin signalling to tighten endothelial barriers and foster follicular growth [ 183 ], while an estrogen-responsive PD-MSC secretome rescues cyclophosphamide-induced POI, restores circadian clock genes and curbs granulosa-cell apoptosis, suggesting cell-free formulations could combine ovarian repair with systemic chronoprotection [ 20 ]. Collectively, four converging mechanisms—BMP-SMAD activation, PI3K/FOXO3 modulation, angiogenic remodelling and redox homeostasis—explain how PD-MSCs and their engineered derivatives revive endocrine and reproductive competence, setting the stage for precision stem-cell or secretome therapies that are both effective and minimally invasive. Umbilical-cord-derived mesenchymal stem cells (UC-MSCs) are emerging as a versatile, minimally immunogenic platform for rescuing compromised ovaries. In a cisplatin-induced POI rat model, exosomes enriched with miR-126-3p from UC-MSCs boosted ovarian angiogenesis, suppressed granulosa-cell apoptosis and normalised E₂, AMH and FSH levels by silencing PIK3R2 and engaging PI3K/AKT/mTOR signalling [ 21 ]. Complementary in-vitro work with frozen-thawed murine ovaries showed that co-culture with UC-MSCs reinforced micro-vessel formation and follicle survival via Wnt/β-catenin activation, an effect amplified in a 3-D Matrigel niche [ 184 ]. Systemic delivery of human UC-MSC exosomes after cyclophosphamide/busulfan exposure restored oestrous cycling, elevated follicle counts and improved fertility, while transcriptomics pointed to immunomodulation and metabolic re-programming as additional contributors [ 23 ]. Mechanistically, UC-MSCs also quell ferroptosis: in an in-vitro ovarian culture system they reversed cisplatin-triggered lipid-peroxide accumulation, reduced fibrosis markers and reinstated hormone secretion [ 185 ]. Finally, clusterin-bearing extracellular vesicles derived from UC-MSCs rescued POF mice by activating PI3K/AKT, curbing granulosa-cell apoptosis and expanding the primordial-to-antral follicle pool—underscoring the potency of cell-free products and the importance of dosing at day six post-chemotherapy [ 186 ]. Collectively, these studies position UC-MSCs and their engineered secretome as a promising, clinically adaptable strategy for reinstating ovarian endocrine and reproductive competence. Endometrium-derived mesenchymal stem cells (EnMSCs) offer a versatile route for ovarian rescue. In a busulfan–cyclophosphamide model of premature ovarian failure, tail-vein infusion of human EnMSCs homed to the stroma, replenished germline stem-cell pools, normalised estrous cycling within four weeks and generated fertile litters, confirming that niche renewal can reverse chemotoxic damage [ 187 ]. Further work shows that EnMSCs elevate Nrf2 in cisplatin injured granulosa cells, curb ferroptosis and preserve developing follicles, adding an antioxidative shield to their reparative repertoire [ 188 ]. Ageing brings mitochondrial erosion rather than acute cell loss, so investigators extracted mitochondria from autologous EnMSCs and microinjected them into germinal-vesicle and MII oocytes. The supplemented oocytes displayed higher mtDNA copy number, improved membrane potential, boosted blastocyst output and nearly doubled live-birth rates after transfer, demonstrating that cytoplasmic quality control can rejuvenate aged gametes [ 189 ]. These complementary mechanisms illustrate how EnMSCs combat both chemotoxicity and senescence. More detailed clinical trials follow below. Beyond the classical bone marrow, adipose, placenta, umbilical cord and endometrium, several unconventional reservoirs of mesenchymal stem cells are being probed for rescuing chemotherapy-injured ovaries. Human hair follicle MSCs delivered intravenously reversed cyclophosphamide-induced premature ovarian failure in mice, restoring hormone profiles, follicle counts and litter size while dampening granulosa-cell ferroptosis through the KEAP1–NRF2–HO-1 axis [ 24 ]. Researchers have also generated scalable MSCs from human pluripotent stem cells through a neural crest intermediate; these cells matched umbilical-cord MSCs in rat models, maintaining estrous cycles, suppressing oxidative stress and apoptosis in granulosa cells and improving mitochondrial function in vivo and in vitro [ 190 ]. A tissue-engineering approach further shows that ovarian cortex-derived stromal cells seeded into decellularised cortical scaffolds form neo-follicles after xenotransplantation, secreting estradiol and anti-Müllerian hormone and suggesting an intrinsic mesenchymal niche capable of follicular reconstruction [ 191 ]. Together these alternative MSC sources broaden the toolbox for ovarian restoration after chemotoxic insult. Embryonic-derived mesenchymal stem cells offer one of the most ambitious attempts to counter natural ovarian ageing in primates. In cynomolgus monkeys, intra-ovarian injection of human embryonic stem cell–derived MSC-like M cells reduced fibrosis and DNA damage, restored sex-steroid secretion, and supported the birth of a healthy infant, changes substantiated by single-cell RNA sequencing that showed dampened oxidative stress and inflammation in granulosa and stromal compartments [ 192 ]. A parallel approach using highly active umbilical-cord MSCs in aged rhesus monkeys converged on similar benefits. These cells homed to senescent granulosa cells, reversed H₂O₂-induced senescence signatures, and remodelled cell–cell communication networks revealed by 10X single-nucleus transcriptomics, which together improved ovarian architecture and endocrine output [ 193 ]. The overlap in anti-fibrotic and anti-oxidative pathways strengthens the biological plausibility of MSC-based rejuvenation, yet the two studies diverge on safety assumptions. M cells originate from pluripotent sources that carry theoretical tumour risk and require rigorous long-term surveillance that the monkey work has not yet provided, while umbilical-cord MSCs possess a more benign track record but still lack reproductive outcome data such as live-births. Clinical translation has advanced fastest with autologous menstrual-blood-derived MSCs. An early pilot in two premature ovarian insufficiency patients reported resumed menses, a 150% rise in serum oestradiol, and improved ovarian volume within seven months after intra-ovarian injection of MenSCs, with no adverse events observed during one-year follow-up [ 194 ]. A subsequent Phase I/II study in fifteen poor ovarian responders showed natural conception in four women within three months, significant gains in oocyte fertilisation and embryo numbers, and a live-birth rate of 33%, outperforming routine ICSI controls despite minimal change in AMH [ 195 ]. A larger non-randomised cohort of 180 women confirmed higher spontaneous pregnancy rates, improved AMH and antral follicle counts two months post-treatment, though efficacy dropped in participants older than forty, hinting at an age ceiling for ovarian niche rescue [ 196 ]. Long-term surveillance of 105 treated women up to three years has now documented a 30% live-birth rate per cycle, no increase in endometriosis, malignancy or autoimmune events, and only one transient ovarian cyst, suggesting acceptable safety when autologous cells are used [ 197 ]. Cross-validation across these platforms indicates that MSCs, whatever their source, act mainly by dampening oxidative injury and restoring stromal–granulosa crosstalk. Yet important questions remain. Primate studies use single injections whereas human trials often rely on bilateral delivery, making dose extrapolation uncertain. MenSC trials lack placebo control and rely on heterogeneous endpoints, so spontaneous pregnancy gains could partly reflect regression to the mean. Conversely, primate investigators report molecular rejuvenation but rarely track fertility endpoints beyond one offspring, leaving translational relevance open. Harmonised protocols and randomised designs will be essential before the impressive laboratory synergy between embryonic, umbilical and menstrual MSCs can be considered truly convergent evidence for clinical benefit. Evidence on cancer risk after MSC therapy for ovarian ageing is mixed and appears highly context-dependent. In a xenograft model, co-injection of human umbilical-cord MSCs with SK-OV-3 cells enlarged primary tumour mass 4.2-fold and seeded liver metastases, showing that paracrine crosstalk can accelerate malignant growth. Intriguingly, prolonged contact drove MSC–cancer cell fusion; the resulting hybrids lost tumorigenicity in NOD-scid mice, suggesting that cell-fusion events may paradoxically curb aggressiveness—but the frequency of such fusion in vivo is unknown, leaving the initial pro-tumour window a clinical concern [ 198 ]. Mechanistic work in patient-derived carcinoma-associated MSCs (CA-MSCs) underscores the danger. Ovarian tumours epigenetically reprogram resident MSCs toward a partial mesenchymal-to-epithelial transition controlled by WT1/EZH2, enabling tight CA-MSC–cancer cell binding and “co-metastasis.” Pharmacological EZH2 inhibition attenuated this metastatic escort function, yet did not abolish it, indicating that even modified MSCs remain metastasis-competent [ 199 ]. By contrast, an ageing-mouse study that injected 3.5 × 10⁵ adipose- or cord-derived MSCs directly into cancer-free ovaries reported zero tumours, negligible ectopic migration and normal cytokine profiles after 16 weeks. However, their model lacks latent malignant cells and the follow-up stops well before typical human relapse intervals; moreover, they used passage-10 MSCs, whereas clinical preparations often expand further, potentially increasing genomic instability [ 200 ]. Taken together, MSCs seem safe in healthy tissue but can amplify residual or dormant ovarian cancer through secreted factors and direct chaperoning. Rigorous pre-screening for minimal residual disease, longer surveillance, and perhaps use of MSCs engineered for suicide switches or EZH2 blockade are prudent before translating ovarian-rejuvenation protocols to oncology survivors. Mesenchymal-stem-cell (MSC) therapy for ovarian injury now pivots on what the cells send rather than what they become. Several groups show that nano-sized extracellular vesicles (EVs) released from MSCs shuttle miRNAs that re-wire survival cascades in granulosa cells. Umbilical-cord-MSC EVs enriched for miR-126-3p enter cisplatin-injured ovaries, repress the PI3K inhibitor PIK3R2 and thus amplify PI3K-AKT-mTOR signalling, coupling angiogenesis with reduced apoptosis [ 21 ]. A parallel study reports that clusterin-laden EVs from the same cell source also converge on PI3K-AKT, rescuing follicle counts when delivered at the optimal sixth day after chemotherapy [ 186 ]. Independent confirmation comes from placenta-MSC transplantation in ovariectomised rats, where secreted factors activate PI3K–FOXO3 to tilt oocyte growth-versus-death decisions [ 179 ], and from miR-21-overexpressing bone-marrow MSCs whose transfer of miR-21 targets PTEN/PDCD4, another brake on AKT activity, to suppress granulosa-cell apoptosis [ 25 ]. Collectively, three distinct cargoes—miR-126, clusterin and miR-21—arrive at the same kinase hub, suggesting a genuine mechanistic intersection rather than cell-type idiosyncrasy. Vascular remodelling emerges as the second recurrent theme. Placenta-MSC infusion boosts ovarian VEGF and downstream GSK3β/β-catenin, enlarging micro-vessels and accelerating folliculogenesis [ 180 ], while PRL-1-enhanced MSCs up-regulate PDGF to thicken luminal calibres and stabilise pericytes [ 181 ]. Adding more depth, an engineered placenta-MSC line that hyper-secretes hepatocyte growth factor (HGF) triggers Wnt/β-catenin and restores follicle maturation; blocking Wnt erases the benefit, arguing that endothelial restructuring is causal, not merely correlative [ 183 ]. These angiogenic routes fit neatly with the miR-126 data, because AKT also feeds into eNOS activation and vascular sprouting, providing cross-validation across different model systems. Beyond vesicles, MSCs can export organelles. Direct transfer of MSC-derived mitochondria, especially when paired with the antioxidant PQQ, enhances SIRT1-PGC-1α biogenesis and dampens the ATM-p53 DNA-damage checkpoint in cyclophosphamide-treated ovaries [ 201 ]. Secretome-only approaches work too: hypomethylated bone-marrow MSCs display a rejuvenated secretory profile whose infusion alone normalises AMH and follicle architecture after cisplatin exposure [ 171 ]. These findings reinforce the idea that the message, not the messenger cell, is therapeutic. Yet some discrepancies warrant caution. Placenta-MSC therapy relies on down-regulating miR-145 to de-repress BMPR2 and activate primordial follicles [ 178 ], a mechanism that could prematurely exhaust the reserve if sustained—an outcome not monitored beyond five weeks. Likewise, most vascular studies use surgical ovariectomy rather than chemotoxic models; whether VEGF- or PDGF-driven neovasculature withstands DNA-damaging environments remains untested. Rigorous, long-term head-to-head experiments will be essential to confirm that these paracrine cascades truly translate into durable fertility rather than short-lived endocrine improvement. Engineering strategies are redefining MSC-based ovarian therapy beyond simple cell infusion.(Fig. 3 ) A first approach seeds umbilical-cord MSCs onto a porous collagen scaffold that is placed intra-ovarian; the matrix traps cells locally for weeks, phosphorylates AKT-FOXO3a/FOXO1 in dormant follicles and produced two pregnancies in long-term POI patients, yet it still involves live-cell transplantation and laparoscopic placement [ 61 ]. Moving to acellular formats, GelMA micro-spheres fabricated by microfluidics encapsulate MSC-derived exosomes pre-loaded with miR-21; sustained release over seven days boosts miR-21 uptake, represses PTEN, activates Akt and markedly reduces granulosa-cell apoptosis, restoring fertility in POI mice while avoiding immunogenic or tumorigenic cells [ 202 ]. Similar carrier logic applies to hyaluronic-acid methacryloyl micro-particles that shelter LPS-preconditioned hUC-MSC exosomes; controlled release enlarges ovarian volume and increases antral follicles after cyclophosphamide injury, implicating paracrine re­vascularisation and microenvironment modulation [ 203 ]. Molecular tailoring can also be done at the vesicle level: MenSC-EVs engineered to enrich HSPA8 up-regulate MGARP and stabilise PRDX2, rescuing mitochondrial integrity in cisplatin-damaged ovaries without introducing whole cells [ 204 ]. Compared with direct MSC injection, these engineered systems prolong therapeutic signals, simplify storage and reduce oncogenic risk; however, they demand sophisticated manufacturing, may deliver a narrower secretome, and their long-term biodegradation or off-target distribution remains less explored. Fig. 3 Engineering Strategy Schematic Diagram for MSC-Based Ovarian Therapy Engineering Strategy Schematic Diagram for MSC-Based Ovarian Therapy

Premature ovarian insufficiency (POI), whether idiopathic or resulting from chemotherapy-induced ovarian failure (CIOF), poses a significant threat to the reproductive and endocrine health of women globally [ 1 , 2 ]. POI affects 1–3% of women under 40 years, while more than 40% of female patients receiving cytotoxic chemotherapy sustain clinically significant compromise of ovarian function [ 3 , 4 ]. In the United States alone, over 120,000 women younger than 50 are diagnosed with cancer each year, highlighting the significant concern of therapy-related gonadotoxicity [ 5 ]. Beyond infertility, abrupt oestrogen deprivation accelerates osteoporosis, cardiovascular disease, mood disorders and overall biological ageing, imposing a lifelong burden on survivors [ 6 , 7 ]. Current ferti-protective strategies only partially mitigate this problem. Cryopreservation of embryos, oocytes or ovarian tissue secures future family-building options but leaves the ovary unprotected during treatment [ 8 ]; pharmacological ovarian suppression with gonadotropin-releasing-hormone analogues (GnRHa) reduces, yet does not abolish, follicular loss [ 9 ]; and hormone-replacement therapy (HRT) alleviates menopausal symptoms without restoring endogenous gametogenic or endocrine capacity [ 10 ]. Assisted reproduction with donor oocytes or gestational surrogacy remains a last resort. Consequently, there is an urgent need for regenerative approaches that can rebuild ovarian architecture and reinstate both fertility and hormonal homeostasis. MSCs have emerged as the leading experimental platform to meet this challenge [ 11 ]. These multipotent stromal cells, obtainable from bone marrow, adipose tissue, umbilical cord, placenta, menstrual blood and other sources [ 12 – 16 ], combine low immunogenicity with a potent secretome rich in cytokines, growth factors and regulatory microRNAs [ 17 , 18 ]. In rodent models of alkylating-agent, platinum-compound or radiation injury, systemic or intra-ovarian delivery of MSCs consistently restores oestrous cyclicity, replenishes primordial- and growing-follicle pools, and even supports live births [ 19 – 24 ]. Mechanistic insights from preclinical studies attribute these benefits primarily to paracrine signaling. MSCs secrete growth factors such as IGF-1, HGF, and VEGF, which inhibit granulosa cell apoptosis and promote angiogenesis. Additionally, MSC-derived exosomes enriched in miRNAs such as miR-21 downregulate apoptotic regulators including PTEN and PDCD4, activate the PI3K–Akt survival pathway, and alleviate oxidative stress [ 25 ]. Importantly, MSCs can also modulate the senescence-associated secretory phenotype (SASP) that characterises the post-chemotherapy ovarian stroma, reducing fibrosis and re-establishing a permissive niche for residual follicles [ 26 , 27 ]. Several pilot studies have investigated the use of bone marrow-derived mesenchymal stem cells (BM-MSCs) to treat POI. Intra-ovarian BM-MSC infusion, via laparoscopy or intra-arterial catheterization, has shown promising outcomes, including improved hormone profiles, recovery of menstruation, and follicular growth, even spontaneous pregnancies [ 28 ]. These trials, although limited in size, support the potential of BM-MSCs to restore ovarian function in women with POI, but larger randomized controlled studies are still needed to confirm efficacy and safety. Nevertheless, three translational bottlenecks temper enthusiasm. First, therapeutic potency varies markedly by tissue source; perinatal MSCs exhibit robust immunomodulation yet shorter in-vivo persistence than adult derivatives, and the molecular basis of these differences remains obscure [ 29 ]. Second, homing and engraftment are inefficient: typically < 1% of infused cells reach the ovary, prompting investigations into CXCR4 over-expression [ 30 ], hypoxic pre-conditioning [ 31 – 33 ] and decellularised-matrix scaffolds [ 34 , 35 ] that localise cells at the lesion site. Third, safety questions persist. While most studies report no tumor-promoting effects, emerging evidence shows that cancer-associated mesenchymal stem cells (CA-MSCs) can enhance ovarian cancer metastasis by increasing tumor heterogeneity through direct mitochondrial transfer [ 36 ]. These findings underscore the need for rigorous long-term surveillance and stringent donor-cell screening in MSC-based therapies. Against this backdrop, the present review aims to provide a critical and up-to-date synthesis of MSC-based ovarian regeneration. We first delineate the clinical burden and molecular pathology of CIOI and POI, highlighting the limitations of current protective or substitutive interventions. We then compare the therapeutic performance of MSCs derived from bone marrow, adipose tissue, umbilical cord, placenta and menstrual blood, dissecting how source-specific secretomes, immunophenotypes and epigenetic profiles influence efficacy. Subsequent sections examine the core mechanisms—anti-apoptotic, angiogenic, antioxidative, immunoregulatory and epigenetic—through which MSCs reprogramme the damaged ovary, and we evaluate complementary strategies such as cell-free exosomes, small-molecule pre-conditioning and bio-engineered “artificial ovaries”. Finally, we identify key knowledge gaps, including standardisation of manufacturing protocols, optimisation of dosing and timing relative to chemotherapy, and development of harmonised endocrine and fertility endpoints for forthcoming randomised trials. By integrating evidence across basic science, translational research and early clinical experience, we seek to chart a rational roadmap for converting MSC technology from experimental promise into clinically robust therapy [ 37 ]. Achieving this goal would address a profound quality-of-life concern and fulfil the unmet need for regenerative solutions that allow life-saving cancer treatment without irrevocable sacrifice of reproductive and hormonal health.

Standard chemotherapy regimens for both ovarian and non-ovarian malignancies rely heavily on DNA-damaging or microtubule-targeting agents that, by design, are indiscriminate toward rapidly dividing cells. Alkylating drugs such as cyclophosphamide, ifosfamide, busulfan and melphalan form inter- and intra-strand DNA cross-links, activating the ATM/ATR–p53 axis in granulosa cells and triggering mitochondrial apoptosis. Platinum compounds (cisplatin, carboplatin, oxaliplatin), the backbone of epithelial ovarian-cancer therapy, generate bulky DNA adducts and abundant ROS, accelerating follicular atresia and stromal fibrosis. Anthracyclines (doxorubicin, epirubicin) inflict double-stranded breaks through topoisomerase-II poisoning and redox cycling, while taxanes (paclitaxel, docetaxel) arrest microtubule dynamics, inducing mitotic catastrophe in growing follicles. Combinations such as paclitaxel–carboplatin for ovarian carcinoma, BEP (bleomycin–etoposide–cisplatin) for germ-cell tumours and CHOP (cyclophosphamide–doxorubicin–vincristine–prednisone) for lymphomas thus expose the ovary to synergistic genotoxic stress. Clinically, these regimens translate into POI rates that can exceed 60% in women over 35 and up to 40% even in adolescents, with long-term declines in estradiol and anti-Müllerian hormone (AMH) [ 4 , 69 ]. Aware of this liability, drug-development pipelines increasingly pursue small molecules that either spare the ovary intrinsically or can be co-administered as pharmacological fertoprotectants. One promising class comprises sphingosine-1-phosphate (S1P) analogues such as fingolimod (FTY-720) [ 125 , 126 ]. By binding S1P receptors on ovarian endothelial and granulosa cells, these agents inhibit intrinsic caspase activation and preserve follicle vascularity in murine models receiving cyclophosphamide or ionising radiation, without blunting antitumour efficacy [ 127 – 131 ]. The inorganic tellurium compound AS101 likewise attenuates oxidative DNA damage and modulates PI3K–Akt signalling; pre-clinical studies show near-complete preservation of primordial-follicle counts when AS101 is co-administered with cisplatin [ 132 – 134 ]. Targeted kinase inhibitors offer a second strategy predicated on tumour-specific oncogene addiction. PARP inhibitors (olaparib, niraparib, rucaparib) have revolutionised maintenance therapy for BRCA-mutated ovarian cancer while exhibiting minimal off-target toxicity toward dormant follicles [ 135 – 138 ], whose low replicative rate renders them less dependent on poly-ADP-ribose-polymerase activity [ 139 ]. Similarly, ABL kinase inhibitors such as imatinib protect oocytes by blocking c-Abl–mediated phosphorylation of the pro-apoptotic factor TAp63α, a pivotal executioner of DNA-damage-induced oocyte death; animal studies confirm that imatinib preserves fertility without compromising cisplatin’s tumouricidal action [ 107 ]. Novel Wee1 inhibitors (e.g. adavosertib) arrest tumour cells in an unscheduled S phase but appear less toxic to quiescent ovarian follicles, although formal reproductive-toxicology data are pending [ 140 , 141 ]. Notably, emerging evidence suggests that combining PARP inhibitors with Wee1 inhibitors may further reduce ovarian toxicity [ 142 , 143 ]. In aggregate, a two-pronged paradigm is emerging: redesign cytotoxics to narrow their biodistribution, and concurrently deploy small-molecule fertoprotectants that intercept DNA damage, oxidative stress or apoptotic checkpoints specifically within the ovary. Although none of the novel agents has yet achieved regulatory approval for routine onco-fertility protection, their rapid progression through translational pipelines forecasts a future in which effective cancer control need not exact so heavy a toll on reproductive potential. A growing portfolio of biologic agents—recombinant proteins, monoclonal antibodies, and antibody–drug conjugates (ADCs)—is reshaping systemic therapy for both ovarian and extra-ovarian malignancies, offering tumour-selective efficacy with substantially less collateral gonadotoxicity than classical cytotoxics [ 144 ]. In ovarian cancer, the VEGF-neutralising antibody bevacizumab was the first biologic to enter frontline and relapse settings; by binding circulating VEGF-A it normalises tumour vasculature, prolongs progression-free survival and, importantly, has shown no consistent suppression of anti-Müllerian hormone (AMH) or disruption of menstrual cyclicity in pre-menopausal recipients [ 145 – 147 ]. A more precise strategy targets the overexpressed folate receptor-α (FRα). The ADC mirvetuximab soravtansine-gynx (Elahere) couples a humanised FRα antibody to the maytansinoid DM4; accelerated FDA approval in November 2022 and full approval in March 2024 for platinum-resistant, FRα-positive epithelial ovarian cancer followed evidence of high response rates and a toxicity profile dominated by reversible ocular effects rather than ovarian failure [ 55 , 148 – 150 ]. FRα biology is also being exploited by the naked antibody farletuzumab, which has progressed to phase III trials. Although the pivotal study did not demonstrate a statistically significant improvement in progression-free survival overall, farletuzumab was well-tolerated and showed no evidence of endocrine toxicity. Subgroup analyses revealed improved outcomes in patients with lower baseline CA-125 levels, supporting continued development in biomarker-enriched populations [ 151 – 153 ]. For non-ovarian solid tumors in young women, HER2-directed biologics offer an instructive template of efficacy with limited ovarian toxicity. The canonical monoclonal antibody trastuzumab revolutionized HER2-positive breast cancer treatment more than two decades ago [ 154 ]. Clinical studies indicate that trastuzumab alone has minimal impact on ovarian reserve, with menses and AMH levels recovering after therapy once cytotoxic chemotherapy is withdrawn, underscoring the ovary-sparing nature of HER2 blockade [ 155 ]. Successive iterations have enhanced potency while retaining favourable selectivity. Trastuzumab deruxtecan (T-DXd), which conjugates a topoisomerase I inhibitor to the trastuzumab scaffold, demonstrates high efficacy across HER2-expressing breast, gastric, and gynaecologic tumours. In terms of safety, although interstitial lung disease has emerged as a notable concern, there is currently no evidence of clinically significant gonadotoxicity [ 156 ]. Meanwhile, sacituzumab govitecan, an anti-TROP-2 ADC bearing SN-38, has gained approvals in metastatic breast and bladder cancer. While clinical studies have not specifically evaluated its effects on estradiol levels or fertility markers, non-clinical repeat-dose toxicity studies in cynomolgus monkeys revealed reproductive system toxicities at high doses (≥ 60 mg/kg, approximately six times the recommended human dose), including endometrial atrophy and increased follicular atresia [ 157 ]. Immune checkpoint inhibitors (ICIs), such as pembrolizumab, are newer large-molecule therapeutics that are generally presumed to spare the ovarian reserve. Although rare case reports of autoimmune oophoritis have been documented, cohort analyses in young women with triple-negative breast cancer suggest that short-course anti-PD-1 therapy does not further exacerbate the decline in anti-Müllerian hormone (AMH) levels beyond that induced by chemotherapy alone. However, emerging preclinical studies indicate that ICIs may impair follicular development and reduce oocyte quality in murine models, prompting renewed concern [ 158 ]. Larger prospective clinical trials incorporating ovarian toxicity endpoints—recently mandated by a consensus statement from the American Society of Clinical Oncology (ASCO)—are now under way to address these translational gaps. Recombinant proteins with endocrine-protective intent are also under investigation. The c-Abl kinase blocker imatinib, while technically a small-molecule, has inspired development of a recombinant fusion protein that sequesters extracellular c-Abl ligands, aiming to shield oocytes from TAp63-mediated apoptosis; pre-clinical proofs-of-concept are driving IND-enabling studies. Similarly, a pegylated recombinant S1P lyase inhibitor designed to elevate sphingosine-1-phosphate systemically has entered phase I testing as a chemo-fertoprotectant. Collectively, these biologic platforms exploit tumour-restricted antigens or immune checkpoints to achieve selective cytotoxicity, thereby limiting bystander damage to quiescent ovarian follicles. Agents already in routine practice—bevacizumab, trastuzumab and mirvetuximab soravtansine—provide compelling clinical precedents, while pipeline ADCs and recombinant modulators promise an expanding repertoire of ovary-sparing therapeutics. Ongoing registrational trials, many of which now incorporate fertility biomarkers as secondary end-points, will ultimately determine whether these large molecules can deliver durable cancer control without sacrificing reproductive potential in an era of increasingly personalised onco-fertility care. A growing body of experimental evidence indicates that several traditional Chinese–medicine (TCM) formulas and their purified constituents can attenuate ovarian damage triggered by cytotoxic chemotherapy, radiotherapy, inflammatory states and even direct tumour burden. These botanicals act through convergent molecular routes—antioxidant defence, anti-apoptotic signalling, mitochondrial preservation and anti-fibrotic modulation—thereby safeguarding both the follicular reserve and steroidogenic function. Salidroside, a phenylpropanoid glycoside isolated from Rhodiola rosea, exemplifies a single-compound strategy with multifaceted protective effects against ovarian insufficiency. In a rat model of cyclophosphamide-induced POI, salidroside (25–50 mg·kg⁻¹·day⁻¹) significantly ameliorated ovarian damage by restoring follicular morphology, elevating serum estradiol and AMH levels, and reducing FSH concentrations. Mechanistically, it upregulated nuclear factor erythroid 2–related factor 2 (Nrf2) and its downstream antioxidant enzyme HO-1, while concurrently downregulating pro-apoptotic proteins p53 and BAX, thus demonstrating dual antioxidant and anti-apoptotic activity [ 159 ]. Beyond its direct effects, salidroside also potentiates stem-cell-based therapies. In a D-galactose-induced POI mouse model, salidroside preconditioning of MSCs markedly enhanced their therapeutic efficacy. This synergistic action was mediated by activation of the Keap1/Nrf2/GPX4 antioxidant axis, which suppressed lipid peroxidation, mitigated ferroptosis, and preserved ovarian function, as evidenced by normalized hormone profiles and follicle counts [ 160 ]. These findings highlight salidroside as both a standalone antioxidant and a sensitizer that boosts the reparative potency of MSCs in POI treatment. Similarly, both Si-Wu-Tang (SWT) and Deer Blood Hydrolysate exert potent ovarian-protective effects by modulating oxidative stress and suppressing apoptosis via the Nrf2/HO-1 signaling axis. SWT, a classical gynecological prescription comprising Rehmannia glutinosa , Angelica sinensis , Paeonia lactiflora , and Ligusticum chuanxiong , significantly enhances ovarian function in cyclophosphamide-induced POI mice. Mechanistically, SWT activates the Nrf2/HO-1 pathway, boosts antioxidant enzyme expression such as SOD, and attenuates lipid peroxidation, while simultaneously promoting angiogenesis via the STAT3/HIF-1α/VEGF cascade, collectively improving follicular microenvironment and reproductive capacity [ 161 ]. Deer Blood Hydrolysate, rich in bioactive peptides, also mitigates D-galactose-induced ovarian senescence through similar antioxidative routes. It markedly reduces ROS and malondialdehyde (MDA) levels, restores glutathione balance, and up-regulates the expression of Nrf2 and its downstream effector HO-1. In parallel, it suppresses the expression of pro-apoptotic markers including Bax and cleaved caspase-3, thereby preserving granulosa cell integrity and delaying ovarian aging [ 162 ]. Resveratrol, a polyphenol from Polygonum cuspidatum , mitigates radiation-induced ovarian damage by restoring SIRT1 expression and suppressing PARP-1-mediated NF-κB activation. This rebalancing of the SIRT1–PARP-1 axis reduces oxidative stress, inflammation, and DNA damage, ultimately preserving follicular integrity [ 163 ]. As with other antioxidant-based interventions, resveratrol reinforces ovarian resilience by targeting key stress-response pathways. Zuogui Pill, a classical TCM formula derived from Jingui Yaolue , has shown efficacy in alleviating ovarian dysfunction in chemotherapy-induced POI models. It inhibits mitochondria-dependent apoptosis of granulosa cells, reduces oxidative stress markers, and restores follicular morphology and hormonal levels, highlighting its potential in ovarian protection [ 164 ]. Yijing Decoction, a multi-herb compound formula including Rehmannia glutinosa and Cuscuta chinensis , improves ovarian function in triptolide-induced POI rats via activation of the VEGF/VEGFR-2/FAK angiogenic pathway. This intervention preserves primordial follicle numbers, restores serum estradiol and AMH levels, and enhances ovarian vascularisation [ 165 ]. Further supporting the mitochondrial protection paradigm, Kuntai Capsule, a TCM-based formulation, alleviates POI by activating the FOXO3/SIRT5 signalling pathway, enhancing mitochondrial biogenesis and reducing apoptotic cell death [ 166 ]. Collectively, TCM-derived compounds and formulas provide a pharmacopeia of ovary-protective agents operating through conserved stress-response and pro-survival pathways. Although most data derive from rodent studies, their consistent engagement of Keap1/Nrf2, SIRT1/FOXO3, VEGF/FAK, and mitochondrial regulatory cascades highlights tangible molecular entry points for future translational work.