Abstract
PURPOSE: To investigate BMAL1 and BMP6 expressive differences in ovarian granulosa cells (OGCs) of patients with polycystic ovary syndrome (PCOS), explore regulatory relationship, assess their impacts on OGC proliferation and apoptosis, and analyze their correlations with ART outcomes of patients. METHODS: A clinical study selected 40 PCOS patients who underwent IVF/ICSI in our hospital from January to October 2022 and 39 controls with male or tubal factor infertility. RT-qPCR and Western blot assessed BMAL1 and BMP6 mRNA/protein levels. The number of oocytes retrieved, 2PN fertilized oocytes, available embryos, and high-quality embryos were compared between groups and analyzed their correlations with BMAL1 and BMP6 expression levels. Cellular experiments were performed by overexpressing or knocking down BMAL1 in KGN cells by plasmid transfection. The dual-luciferase reporter assay was used to identify BMAL1/BMP6 regulatory relationship. CCK-8 and flow cytometry assessed cellular proliferation and apoptosis. RESULTS: BMAL1 mRNA/protein expression (P < 0.001) in the PCOS group was significantly lower than that in controls, as was the number of high-quality embryos (P = 0.001). Contrastingly, BMP6 (P < 0.001) was significantly higher in the PCOS group. BMAL1 expression levels were negatively correlated with BMP6 (r = - 0.684, P = 0.002) and positively correlated with the number of 2PN fertilized oocytes, available embryos, and high-quality embryos (r = 0.659, P = 0.003; r = 0.623, P = 0.006; and r = 0.738, P < 0.001). Cellular experiments showed that overexpression of BMAL1 significantly decreased relative luciferase activity (P < 0.01). Overexpression of BMAL1 significantly decreased KGN cell apoptosis (P < 0.01) and enhanced proliferation (P < 0.01). CONCLUSION: BMAL1 regulates OGCs proliferation and apoptosis by targeting BMP6, thereby influencing ART outcomes in patients with PCOS. This study might provide molecular factors that indicate ART outcomes and therapeutic targets for PCOS. TRIAL REGISTRATION: Registration number: ChiCTR2100052331; registration date: 2021-10-24.