{"paper_id":"e694fac7-fb71-4b4b-884b-8555edb542a6","body_text":"Abstract\nBuserelin, a gonadotropin-releasing hormone agonist, reduces gonadotropin and estrogen levels and is commonly used to alleviate the symptoms of endometriosis. Vitamin D3 has been reported to exhibit anti-inflammatory and pro-apoptotic properties, which may contribute to the regression of endometrial lesions. We aimed to investigate the effects of vitamin D3 on the regression and recurrence prevention of endometrial implant sites through the induction of apoptosis comparable to buserelin acetate in an experimental rat endometriosis model. Endometrial implant size and adhesion scores were evaluated following treatment. Microscopic analyses were performed using hematoxylin–eosin-stained preparations. Apoptotic activity was assessed by TUNEL assay, along with the expression of Bcl-2 and Bax antibodies. Untreated rats exhibited larger implant volumes, severe glandular and stromal alterations, and pronounced inflammatory infiltration. In contrast, vitamin D3 and buserelin treatments reduced implant size and adhesion scores. The vitamin D3–treated group demonstrated a high density of TUNEL-positive cells. Increased expression of Bcl-2 protein was found in untreated groups whereas, increased expression of Bax protein was found in both treated groups. In conclusion, vitamin D₃ may have contributed to the regression of endometrial implants, possibly through mechanisms involving apoptotic pathways. 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Authors read and approved the final manuscript.\nCorresponding author\nEthics declarations\nConflict of interest\nThe authors declare no Conflict of interest.\nAdditional information\nPublisher’s note\nSpringer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.\nRights and permissions\nSpringer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.\nAbout this article\nCite this article\nKöylü, A., Ömeroğlu, S., Dizakar, S.Ö.A. et al. Vitamin D3 promotes regression of endometrial implants comparable to buserelin in a rat model of endometriosis. J Mol Histol 57, 216 (2026). https://doi.org/10.1007/s10735-026-10879-z\nReceived:\nAccepted:\nPublished:\nVersion of record:\nDOI: https://doi.org/10.1007/s10735-026-10879-z","source_license":"public-domain-us","license_restricted":false}