To explore the regulatory role of progesterone in luteolysis via cyclooxygenase-2( COX-2) /prostaglandin F2α ( PGF2α) signal pathway in livestock, the ovine endometrium explants were cultured and treated with specific inhibitor of progesterone receptor ( onapristone) . The PGF2α concentration and mRNA and protein expression levels of PGF2αsyn-thesis-related enzyme COX-2 were detected. The applications of onapristone ( 0. 2μmol/L, 2. 0μmol/L or 20. 0μmol/L) in ovine endometrium culture medium inhibited the PGF2αsecretion, especially when the explants were cultured for 72 h in the presence of 20. 0μmol/L onapristone ( P<0. 05) . In addition, the mRNA expression of COX-2 was suppressed in endo-metrial explants cultured with onapristone for 24 h, 48 h and 72 h ( P<0. 01) . The endometrial COX-2 protein expression was also downregulated significantly after 20. 0 μmol/L onapristone treatment for 72 h, only about 23% of the control. In conclusion, progesterone regulates luteolysis via progesterone receptor/ COX-2 / PGF2α signal pathway in sheep, and COX-2 seems to be the primary enzyme re-sponsible for PGF2α production.%为了探讨孕酮通过环氧合酶-2(COX-2)/前列腺素2α(PGF2α)信号通路调节家畜黄体溶解的作用机制,本研究采用孕酮受体的特异抑制剂Onapristone处理体外培养的绵羊子宫内膜组织,检测分泌到培养液中的PGF2α浓度以及子宫内膜中PGF2α合成过程中关键酶基因COX-2的mRNA和蛋白质表达水平.结果显示,Ona-pristone添加到子宫内膜组织培养液中后,内膜组织合成分泌的PGF2α浓度明显下降,且抑制了COX-2 mRNA和蛋白质表达水平,高剂量的Onapristone(20.0μmol/L)处理72 h后COX-2的蛋白表达水平仅为对照组的23%.表明,孕酮通过其受体介导的COX-2/PGF2α信号通路调节家畜的黄体溶解过程,且COX-2对于PGF2α的合成起到重要的作用.
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