iNOS介导超重特异晕蛋白SWP诱发精子活力降低作用机制的研究

There are many adverse effects of hypergravity on reproductive system of astronauts during space flight.Our group found that Swiprosin-1 (SWP) was a testicular highly expressed protein stimulated by hypergravity. Hypergravity stimulation or SWP over-expression in testis could increase the expression of the induced nitric oxide synthase(iNOS) and nitric oxide(NO), while reduced the sperm motility.Therefore, we use SWP knockout mice stimulated with hypergravity as the model to study the effects of SWP on regulation of NO secretion and sperm motility. Wide type mice which are stimulated with hypergravity are as control. We use iNOS RNAi in WT mice and iNOS over expression in SWP knockout mice to analyze the effect of iNOS and SWP expression on sperm motility and the regulation of these two genes. In addition, we detect NO production, the expression of iNOS and SWP in the testicular tissue of the infertile patients due to low sperm motility to analyze the relationship between SWP expression and sperm motility. With these animal models and clinical studies, we will reveal the mechanism of infertility caused by reduced sperm motility after hypergravity stimulation, and provide theoretical and experimental basis for the treatment of infertility in clinics.

在宇宙空间飞行过程中，重力场改变形成的超重刺激对宇航员生殖系统可产生诸多不利影响。课题组研究发现超重刺激后晕蛋白Swiprosin-1（SWP）在睾丸内特异性高表达，预实验进一步发现超重刺激或病毒载体高表达SWP可诱导iNOS基因及蛋白表达上调，NO生成量增加，进而诱发精子活力降低。故本课题将以SWP基因敲除小鼠和野生型超重刺激小鼠为模型，深入研究超重刺激后SWP蛋白对iNOS基因蛋白表达的调控作用及其机制，以及对精子活力的影响；通过对野生型小鼠iNOS基因RNA干扰，和对SWP敲除小鼠iNOS基因过表达，验证iNOS介导晕蛋白SWP诱发精子活率降低的这一机制。同时，收集临床上精子活率低下不育患者的睾丸组织，检测iNOS和SWP基因蛋白表达水平，研究SWP在不育人群中的表达情况，揭示iNOS介导晕蛋白SWP诱发精子活力降低的不育机制，为此类不育症的基因治疗和新药研发提供科学依据。

男性不育发病率呈逐年上升趋势，50%不孕不育是由男性不育造成，病因复杂多样。在宇宙空间飞行过程中，重力场改变形成的超重刺激对宇航员生殖系统可产生诸多不利影响。已有研究发现超重刺激后晕蛋白Swiprosin-1（SWP）在睾丸内特异性高表达，超重刺激或病毒载体高表达SWP可诱导iNOS基因及蛋白表达下调，NO生成量减少，进而诱发精子活力降低。在本研究中课题组以超重刺激的SWP基因敲降和野生型小鼠为模式动物，研究了SWP基因对超重刺激诱发精子活力降低的影响，体外培养小鼠睾丸间质细胞SWP基因敲降以及iNOS基因过表达和RNA干扰对其NO生成量的影响，iNOS基因RNA干扰和过表达对超重刺激诱发精子活力降低的影响，以及临床上精子活力低下不育患者睾丸组织iNOS和SWP基因表达情况。研究结果发现：小鼠睾丸间质细胞中SWP基因过表达可以下调iNOS基因表达，SWP基因敲降可以明显抑制超重刺激造成NO生成量和精子活力降低的作用，睾丸间质细胞在体过表达或者RNA干扰iNOS基因明显能够增加或者降低NO的生成量，进而可以消除iNOS过表达模型小鼠或加剧iNOS敲降模型小鼠超重刺激造成精子活力降低的作用，在临床不育患者的睾丸组织中发现部分患者出现iNOS基因低表达现象。该研究揭示了iNOS介导的晕蛋白SWP诱发精子活力降低的不育机制，为此类不育症的基因治疗和新药研发提供科学依据。