Duo Nang Decoction enhances endometrial receptivity in PCOS rats by upregulating caveolin-1 expression

Background: Duo Nang Decoction (DND) is widely used for treating polycystic ovary syndrome (PCOS)-related infertility. However, the molecular mechanisms underlying its action remain unclear. In a previous study, downregulation of caveolin-1 (Cav-1) was shown to impair endometrial angiogenesis, a key determinant of endometrial receptivity. Objectives: This research study aimed to elucidate the influence and potential molecular mechanisms of DND on endometrial receptivity, specifically focusing on Cav-1 in PCOS rats. Methods: Sprague Dawley (SD) rats (females, 3-week-old) were randomly categorized into the DND and aspirin cohorts. After successful PCOS modeling, the rats were orally administered DND or aspirin, respectively. Then, ovulation was induced and mating was performed. The rats were euthanized on the 2nd and 5th day of conception and the endometrium was extracted for histological evaluation via hematoxylin and eosin (HE) staining. Furthermore, immunohistochemistry (IHC) staining was carried out to assess Cav-1, vascular endothelial growth factor (VEGF) and ?-catenin levels, as well as endometrial microvascular density (MVD). Moreover, reverse transcription polymerase chain reaction (RT-PCR) was used to measure the mRNA levels of VEGF and Cav-1 in the endometrium of both groups. Results: The HE and IHC staining, as well as RT-PCR analysis of endometrial tissue slices, revealed that on the 2nd and 5th day of conception, both groups indicated significantly increased endometrial thickness, MVD and elevated levels of VEGF, Cav-1 and ?-Catenin. However, the MVD in the DND group was substantially higher relative to the aspirin group. Conclusion: This study revealed that DND significantly enhanced endometrial angiogenesis and improved endometrial receptivity in PCOS rats. Mechanistically, the effects of DND on endometrial receptivity may be associated with the upregulation of Cav-1 and ?-catenin. However, the specific mechanism of action warrants further research.