FoxO3a转录因子对不同直径猪卵泡中颗粒细胞的调节

The Regulating Function of FoxO3a Transcription Factor to Granulosa Cells of Follicles of Different Diameters

哺乳动物卵泡的生长和发育过程中,大多数卵泡发生闭锁,只有少数卵泡能发育成熟并排卵,卵泡颗粒细胞的凋亡将诱发卵泡闭锁.FoxO3a是调控细胞生长和凋亡的重要转录因子之一,在猪卵巢颗粒细胞中特异性表达.该试验用机械法分离卵泡,按直径大小分为:小卵泡(1.5—3mm)、中卵泡(3—5 mm)和大卵泡(≧5 mm)3组,分别统计健康卵泡和闭锁卵泡所占比率,分离颗粒细胞(pGC).用AnnexinⅤ-FITC/PI双染法流式细胞术检测pGC存活率,Western blot检测pGC内FoxO3a表达水平.结果表明:随卵泡直径的增大,闭锁卵泡的比率逐渐降低(P<0.05),健康卵泡的比率增加(P<0.05);pGC存活率升高(P<0.05);pGC内FoxO3a表达水平逐渐升高(P<0.05).可见:FoxO3a转录因子可能通过抑制卵泡颗粒细胞的凋亡,从而调节猪卵泡的生长和闭锁.

Most follicles in mammalian ovaries undergo a degenerative progress known as atresia, and thus only a limited number of ovarian follicles actually ovulate after full growth and development. Follicular atresia is primarily induced by granulosa apoptosis. The apoptosis of granulosa cells from follicles of different diameters was investigated. Granulosa cells were isolated from small （1. 5-3 mm）, middle （3-5 mm） and large （larger than 5 mm） antral follicles. The survival rates of granulosa cells and [ Ca^2＋ ] i were detected by FACS, and the expression of FoxO3a was detected by Western blot. The results showed that the rate of atresic follicles decreased, and the rate of the healthy follicles increased at the same time ; the survival ratio of pGC from small follicles was the lowest （ P 〈 O. 05 ） ; the expression of FoxO3a increased with the follicullar diameters increasing. The results indicate that FoxO3a transcription factor may inhibit the apoptosis of pGC and hence regulate the atresia of follicles.