MicroRNAs (miRNAs) are endogenous non-coding RNAs in eukaryotic cells that modulate apoptosis of ovarian granulosa cells (GCs), which is an important cause of mammalian follicular atresia. In the present study, associations were evaluated between miR-21-5p and the extent of Smad7 protein production in regulation of ovarian granulosa cell (pGC) apoptosis. There was detection of miR-21-5p and Smad7 primarily in the cytoplasm and nucleus of pGCs, respectively. When there was an enhanced abundance of miR-21-5p and decreased abundance of Smad7 there were similar effects in pGCs, including inducing proliferation, inhibiting apoptosis, increasing the number of cells in S and G2/M phases, increasing serum estradiol, and decreasing serum progesterone concentrations. Furthermore, the Smad7 mRNA transcript was identified as a target for miR-21-5p actions, with enhanced abundances of miR-21-5p being associated with a lesser abundance of Smad7 mRNA transcript and protein in pGCs. Overall, results from the present study indicate that miR-21-5p has actions on the Smad7 mRNA transcript during the process of ovarian granulosa cell apoptosis in pigs.

MicroRNA (miRNA) 是真核细胞中的内源性非编码 RNA，可调节卵巢颗粒细胞 (GC) 的凋亡，这是哺乳动物卵泡闭锁的重要原因。在本研究中，评估了 miR-21-5p 与Smad7蛋白产生程度在调节卵巢颗粒细胞 (pGC) 凋亡中的关联。分别主要在pGCs的细胞质和细胞核中检测到miR-21-5p和Smad7。当 miR-21-5p 丰度增加而Smad7丰度降低时在 pGCs 中也有类似的作用，包括诱导增殖、抑制细胞凋亡、增加 S 期和 G2/M 期细胞数量、增加血清雌二醇和降低血清孕酮浓度。此外，Smad7 mRNA 转录物被鉴定为 miR-21-5p 作用的靶标，miR-21-5p 丰度的增加与 pGC 中Smad7 mRNA 转录物和蛋白质的丰度较低有关。总体而言，本研究的结果表明，在猪卵巢颗粒细胞凋亡过程中，miR-21-5p 对Smad7 mRNA 转录物有作用。