The role of curcumin in enhancing endometrial receptivity in a rat model of adenomyosis: A preclinical basis for herbal therapeutics development

HIGHLIGHTS Nano-curcumin increases expression of endometrial receptivity markers HOXA10, LIF, and integrin ß3 in adenomyosis rat models. Nano-curcumin shows potential as a non-surgical therapy to improve implantation in adenomyosis without affecting lesion severity. ABSTRACT Objective: This study aimed to evaluate the effects of nano-curcumin on markers of endometrial receptivity in a rat model of adenomyosis, focusing on lesion characteristics and gene expression related to embryo implantation. Materials and Methods: An experimental study was conducted using 30 female Wistar rats (Rattus norvegicus) at the Biomedical Laboratory, Faculty of Medicine, Universitas Riau, from March to October 2024. The rats were randomly assigned into five groups: control, adenomyosis model, and adenomyosis treated with nano-curcumin at doses of 25, 50, and 75 mg/kg body weight. Adenomyosis was induced via oral administration of tamoxifen (2.7 µmol/kg) from postnatal day 2 to 5. Nano-curcumin was administered orally for 15 consecutive days starting 75 days after induction. Adhesion scores, lesion number, and lesion volume were evaluated, while expression levels of HOXA10, Leukemia Inhibitory Factor (LIF), and integrin β3 were quantified using polymerase chain reaction assays during days 4–6 of pregnancy. Results: Nano-curcumin reduced lesion count, lesion volume, and adhesion scores in a dose-dependent manner; however, these changes were not statistically significant (all p > 0.05). In contrast, nano-curcumin demonstrated a clear dose-dependent enhancement of endometrial receptivity. Expression of HOXA10, LIF, and integrin β3—markers suppressed in the adenomyosis group—was progressively restored toward control levels with increasing doses, indicating improved endometrial readiness for implantation despite minimal changes in lesion morphology. Conclusion: Nano-curcumin enhances the expression of key endometrial receptivity markers without significantly affecting lesion characteristics in rats with adenomyosis, suggesting its potential as a therapeutic agent to improve fertility outcomes.