Abstract: Objective　To study the effect of microRNA-141 (miR-141) on the proliferation of ovarian granulosa cells and to explore its mechanism in the occurrence and development of polycystic ovary syndrome (PCOS). Methods　qPCR was used to detect the expression levels of miR-141 mRNA in 20 samples PCOS ovarian tissues, 20 normal ovarian tissue specimens, human ovarian granulosa cells KGN and human normal ovarian epithelial cells IOSSE80. KGN cells were divided into miR-141 minics group, LY294002+miR-141 minics group, rapamycin+miR-141 minics group, NC group and control group. The MTT method and the plate cloning experiment method were used to detect the cell proliferation and clone formation ability of each group, and the Western blot assay was used to detect the phosphatidylinositol 3-kinase (PI3K)/protein kinase (Akt)/mammalian rapamycin target protein (mTOR) signaling pathway related protein expression levels. Results　The expression level of miR-141 mRNA was significantly higher in PCOS ovarian tissue than that in normal ovarian tissue, and the expression level of miR-141 mRNA was significantly higher in human ovarian granulosa cells KGN than that in normal ovarian epithelial cells IOSE80 (P＜0.05). miR-141 mRNA expression levels were significantly higher in miR-141 minics group, LY294002+miR-141 minics group and rapamycin+miR-141 minics group than those in NC group and control group (P＜0.05). After transfection for 24, 48, 72 and 96 h, the OD values and clone formation rates were lower in LY294002+miR-141 minics group and rapamycin+miR-141 minics group than those of miR-141 minics group, but higher than those of NC group and control group (P＜0.05). After transfection, the expression levels of p-Akt and p-mTOR were lower in LY294002+miR-141 minics group than those in miR-141 minics group, but higher than those in NC group and control group (P＜0.05). The expression level of p-mTOR protein was significantly lower in rapamycin+miR-141 minics group than that in miR-141 minics group, and higher than that in NC group and control group (P＜0.05). Conclusion　miR-141 can promote proliferation of ovarian granulosa cells by activating the PI3K/Akt/mTOR signaling pathway.

Key words: polycystic ovary syndrome, phosphatidylinositol 3-kinases, granulosa cells, protein kinase B, miR-141, ovarian granulosa cells, PI3K/Akt/mTOR signaling pathway