科研之友
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摘要
The present study was conducted to investigate the involvement of nitric oxide (NO) in cumulus expansion, oocyte mortality and meiotic maturation of porcine cumulus enclosed oocytes (CEOs) cultured in two different models when gonadotropins, including follicle-stimulating hormone (FSH) and human chorionic gonadotropin (hCG) were presented or not. And the interaction between NO and beta-mercaptoethanol (beta-ME), a free radical scavenger was also investigated. Two models refer to spontaneous maturation model and hypoxanthine (HX) medium model. All the 3,433 eligible CEOs were incubated at 39degreesC and the cumulus expansion, oocyte morphology and nuclear phase were evaluated 44 h after incubation. (1) In spontaneous maturation model, NO stimulates the cumulus expansion and beta-ME delayed it. NO doesn't affect the oocyte meiotic resumption but inhibits the oocytes to develop to metaphase II. (2) In HX medium model, NO or beta-ME doesn't affect the expansion in the absence of gonadotropins, but in the presence of gonadotropins, NO or beta-ME inhibits the expansion. In the presence of gonadotropins, NO inhibits the oocyte meiotic resumption and it especially inhibits the oocyte to develop to metaphase II, and beta-ME reverses such inhibitory effects. The cooperation of gonadotropins and beta-ME stimulates the meiotic resumption and especially, promotes the CEOs to develop to metaphase II in both models. Moreover. HX might contribute to the fragility of oocyte zona pellucida and gonadotropins, nitric oxide and beta-ME could alleviate it separately, and cooperatively. It is concluded that NO exerts different functions in two models and beta-ME affected the functions of NO in different models.
- 出版日期2004-3
- 单位中国农业大学
