不同日龄小鼠卵丘颗粒细胞对卵泡刺激素/缺氧诱导因子-1信号通路的影响

Response to FSH activated HIF-1 signaling pathway of granulosa cells in the mice at different ages

目的研究不同日龄小鼠颗粒细胞对卵泡刺激素(FSH)诱导的缺氧诱导因子-1/血管内皮细胞生长因子(HIF-1/VEGF)信号通路的影响。方法超排卵方法取出卵母细胞和颗粒细胞,进行体外受精;荧光素酶报告基因实验检测常氧和低氧培养条件下,不同日龄小鼠卵丘颗粒细胞对FSH诱导的HIF-1/VEGF信号通路的应答;蛋白质免疫印迹技术检测FSH受体的表达水平。结果雌性小鼠超排卵数和卵母细胞体外受精能力与小鼠日龄数呈负相关;FSH上调小鼠卵丘颗粒细胞HIF-1α的转录活性;免疫印迹结果显示小鼠颗粒细胞中FSH受体的表达水平随着日龄数的增加呈下降趋势。结论小鼠卵丘颗粒细胞对FSH诱导的HIF-1/VEGF信号通路的应答反应随小鼠天日龄数增加而下降,与颗粒细胞表面FSH受体的表达下降相一致。雌性小鼠随着年龄增加引起的生殖能力下降可能与颗粒细胞表面FSH受体表达减少有关。

Objective： To explore the response to follicle-stimulating hormone （FSH） -induced hypoxia-inducible factor-1（HIF-1）/ vascular endothelial growth factor （VEGF） signaling pathway of granulosa cells （GCs） in the mice at different ages. Methods： Five groups of mice at different ages were used： 20-30 days （A）, 50-60 days （B）, 80-90 days （C）, 110-120 days （D） and more than 120 days （E）. Mature oocytes were collected from the oviducts of mice superovulated with pregnant mare serum gonadotropin （PMSG） and human chorionic gonadotropin （hCG）. In vitro fertilization （IVF） was performed on all groups after superovulation. The luciferase reporter gene assay was used to evaluate the response to FSH-induced HIF-1/VEGF signaling pathway in GCs under normoxic and hypoxic conditions. Western blotting was also used to elucidate the expression of FSH receptor of GCs in each group. Results： The number of superovulated oocytes and the capacity of in vitro fertilization of the mature oocytes showed a decline in an age-dependent manner. FSH promoted HIF-1-dependent transactivation in the mouse GCs. FSH-stimulated HIF-1 activity was declined in GCs of aged mice, especially those in D and E group. The levels of FSH receptor in GCs by western blotting also showed the aging-related decrease. Conclusions： The results suggest that response to FSH-induced HIF-1/VEGF signaling pathway in GCs of mouse decrease with the advance of age and correlate with the expression of FSH receptor.Aging-related decline in fertility in female mice might be correlated with the decreased expression of FSH receptor in granulosa cells.