褪黑素对热应激条件下山羊精子发生障碍的保护作用及机制研究

热应激引起的种畜精子发生异常、繁殖性能下降是畜牧生产中普遍存在并亟待解决的重要问题。前期初试表明，热应激会引起小鼠精母细胞内质网应激和凋亡，推测这可能是导致精子发生异常的原因。褪黑素可调控细胞凋亡过程，但其在热应激所致山羊精子发生障碍中的作用机制尚未探明。本项目拟在已有基础上，采用智能环控仓模拟高温环境处理试验动物奶山羊，研究热应激对其睾丸组织及精液品质的影响；构建内质网应激信号通路关键分子过表达和干扰表达慢病毒载体并感染原代奶山羊精母细胞，筛选影响精母细胞凋亡的关键内质网应激通路，进一步分析、筛选和验证该通路可能作用的下游靶基因及互作机制；褪黑素预处理热应激精母细胞，探明其通过内质网应激通路预防或缓解热应激致山羊精子发生异常的作用机制；在体试验验证褪黑素对热应激所致山羊精子发生障碍的保护效果。该研究可为防治热应激所致公羊气候性不育提供分子靶标和科学依据，并为畜牧业生产新技术提供理论基础。

The abnormality of spermatogenesis and the decline of reproductive performance of breeding stock induced by heat stress is a vital problem and need to be solved urgently in animal husbandry. Previous studies have preliminarily shown that heat stress can induce endoplasmic reticulum stress（ERS） and apoptosis in mouse spermatocytes, which may be the cause of spermatogenesis abnormality. Melatonin can regulate the cell apoptotic process, but its mechanism of action on goat sperm disturbance caused by heat stress has not been clarified. Based on the existing foundation, this study intends to use intelligent environmental control bins to simulate the high-temperature environment to treat experimental animal milk goats and study the effect of heat stress on the testicular tissue and semen quality. The overexpression and interference lentivirus vectors of the key molecules of ERS signaling pathway are constructed and infected primary dairy goat spermatocytes. The key ERS signaling pathway affecting the apoptosis of spermatocytes are screened. Further，we analyze, screen and verify the downstream target genes of this signaling pathway and their interaction mechanism. Heat stress treated spermatocytes are pretreated by melatonin to explore its mechanism of preventing or alleviating spermatogenesis abnormalities through the ERS signaling pathway in dairy goats. Finally, in vivo test is performed to verify the protective effect of melatonin on the spermatogenesis disorder of dairy goats caused by heat stress. This study can provide molecular targets and scientific basis for the prevention and treatment of heat stress-induced climatic sterility in rams, and provide theoretical basis for new technology of animal husbandry.