{"paper_id":"5d1776b4-9098-4617-9d40-304b17646626","body_text":"Abstract\nBackground\nOvarian endometrioma (OEM) is a leading cause of infertility in women of reproductive age; however, the cellular and molecular mechanisms by which it impairs ovarian function remain poorly understood. Direct investigation of OEM-induced ovarian dysfunction is hampered by the difficulty in obtaining clinical ovarian tissue samples, and the lack of stable animal models that faithfully simulate the pathological features of human OEM represents a critical bottleneck in this field.\nMethods\nA rat model of OEM was established by suturing homologous rat endometrial tissue onto the ovarian surface. The impact of OEM on ovarian function was evaluated through the estrous cycle, serum hormone levels, and histopathological staining. Single-cell RNA sequencing (scRNA-seq) was employed to analyse ovarian tissue from the OEM group and the control group, with the aim of mapping cellular landscapes, identifying the composition of cell subpopulations, conducting differential gene enrichment analyses, and characterising changes in differentiation trajectories and intercellular communication networks. Key phenotypic findings were further validated through histopathological staining, immunofluorescence, Real-time Reverse Transcription PCR, and Western blot.\nResults\nA rat model of OEM was successfully established by suturing homologous rat endometrial tissue onto the ovarian surface. Estrous cycle monitoring revealed disrupted estrous cycles in OEM model rats. ELISA demonstrated significantly decreased serum AMH and E2 levels, accompanied by elevated FSH levels in the OEM group. CD10 immunostaining confirmed the positive expression of endometrial tissue, and Prussian blue staining revealed markedly increased iron deposition in the OEM group ovaries. The scRNA-seq identified a total of 70,041 cells, revealing seven major cell types. OEM significantly altered the cellular composition of the ovary, with decreased proportions of granulosa and endothelial cells and an increased overall proportion of immune cells; within the immune-cell compartment, the proportions of macrophages and B cells decreased, whereas those of T cells and neutrophils increased. Granulosa cell analysis revealed disrupted differentiation trajectories, attenuated intercellular AMH and Estradiol signaling, and significantly downregulated mRNA and protein expression of AMH, FSHR, and ESR2 in the OEM group. Stromal cell analysis demonstrated significant enrichment of TGF-β and collagen signaling pathways, with upregulated mRNA and protein expression of COL1A1, TGFB1, and ACTA2 in the OEM group. Masson’s trichrome and Sirius Red staining confirmed significantly increased fibrotic areas in the OEM group ovaries. Immune cell analysis revealed significant enrichment of chemokine signaling and IL-17 signaling pathways, enhanced CCL and CXCL chemokine communication networks, and upregulated mRNA and protein expression of inflammatory mediators, including CXCL1, CCL2, and IL1b in the OEM group.\nConclusions\nThis study successfully established a rat model that simulates the key pathological features of OEM. Utilizing scRNA-seq, we constructed, for the first time, a comprehensive cellular landscape of the OEM-affected ovary, revealing the synergistic effects of granulosa cell dysfunction, ovarian stromal fibrosis, and immune dysregulation in OEM-induced ovarian functional decline.\nSimilar content being viewed by others\nAcknowledgements\nWe appreciate every author for their assistance with the experiments and constructive comments on the manuscript.\nFunding\nThis work was supported by the National Natural Science Foundation of China [grant numbers. 82374513], Scientific and technological innovation project of China Academy of Chinese Medical Sciences [grant numbers. CI2021A02402].\nAuthor information\nAuthors and Affiliations\nCorresponding authors\nEthics declarations\nEthics approval and consent to participate\nExperimental Animal Ethics Committee of the China Academy of Chinese Medical Sciences approved all the experimental procedures used in this study (Ethics Approval No. IACUC-GAMH-2026-004-01).Not applicable.\nConsent for publication\nNot applicable.\nCompeting interests\nThe authors declare no competing interests.\nAdditional information\nPublisher’s note\nSpringer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.\nSupplementary Information\nRights and permissions\nOpen Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.\nAbout this article\nCite this article\nJIA, Z., HU, G., GUO, Y. et al. A novel rat model of ovarian endometrioma: single-cell RNA sequencing reveals its impact on ovarian function. J Ovarian Res (2026). https://doi.org/10.1186/s13048-026-02313-5\nReceived:\nAccepted:\nPublished:\nDOI: https://doi.org/10.1186/s13048-026-02313-5","source_license":"CC0","license_restricted":false}