尿激酶型纤溶酶原激活因子在小鼠精-卵接触前通讯和体外受精中作用初探

Role of Urokinase-type Plasminogen Activator in the Pre-contact Sperm-egg Communication and Fertility of Mice in Vitro

目的:探讨尿激酶型纤溶酶原激活因子(uPA)在雄性促生育中的作用机制。方法:通过检测精子在毛细管内聚集数量的变化来测试小鼠精子体外对uPA和卵细胞的趋化性,以及将卵细胞分别经uPA、uPA抑制剂(PAI-1)以及抗-uPAR抗体预处理后,检测其趋化诱导精子的能力,来反应uPA在精-卵接触前通讯中的作用。其次观察精子经uPA预处理后其受精能力的变化。结果:精子在递减uPA浓度梯度中的聚集数量明显低于等浓度内的(P<0.05);经uPA预处理的卵细胞其聚集精子的能力显著强于未经处理的卵细胞(P<0.05),而用PAI-1预处理卵细胞后,卵细胞聚集精子的能力显著下降(P<0.05);用抗-uPAR抗体预处理卵细胞并不影响卵细胞对精子的聚集作用;uPA处理后的精子与卵细胞共孵育后其受精卵数目多于未经处理的(P<0.05)。结论:精子在体外对uPA和卵细胞均有趋化性;uPA能增加卵细胞对精子的趋化作用,增进精-卵接触前通讯,促进受精。本实验在一定程度上探讨了uPA促男性生育的机制,并为其在临床上的应用提供一定的理论依据。

Objective： To study the role of uPA in pre-contact sperm-egg communication and fertility of mice in vitro, and to explore the possible mechanisms of uPA on male infertility therapy. Methods： In this study, firstly, sperm chemotaxis（SC） was assayed by counting the number of spermatozoa accumulating in capillary with a descending gradient or no-gradient of uPA in it. The uPAR of spermatozoa was inhibited by the use of anti-uPAR antibody, the number of spermatozoa accumulating in capillary was also counted. Secondly, after pretreated with uPA, PAI-1 and anti-uPAR antibody respectively, the eggs were put into capillaries. And the number of spermatozoa accumulating in capillary was counted respectively. Lastly, after pretreated with uPA, the spermatozoa was observed to fertilize eggs, and then the number of fertilized eggs were counted. Results： The data showed that the number of spermatozoa in a descending gradient of uPA was remarkably lower than that in a no-gradient of uPA （P〈0.05）. Inhibiting uPAR of spermatozoa also held back the SC induced by uPA （P〈0.05）. And the number of spermatozoa attracted by egg, which was treated with uPA in advance, increased significantly than that of attracted by no-treated eggs. On the contrary, the number of spermatozoa accumulating in capillaries decreased correspond- ingly when the egg was pretreated with PAI-1 （P〈0.05）. And the number of fertilized eggs increased obviously when spermatozoa had been pretreated with uPA. Conclusion： These results suggest that uPA could enhance the capability of egg inducing spermatozoa chemotaxis, and improve the fertilization capability of spermatozoa. Thus, uPA may act as an attractant during precontact sperm-egg communication, increase the chance encounter of spermatozoa and eggs, therefore, enhance the fertility success correspondingly. This study, in some degree, provides an evidence that uPA may be used as a new medicine for male infertility.