氧化应激介导纤溶蛋白酶对精索静脉曲张附睾上皮的损伤机制

Most of the studies performed on the mechanism of varicocele related infertility are focused on the tests , but not yet about the impact of varicocele on epididymis . In our previous studies, we confirmed the NBC channel and CFTR channel of epididymal cell play important roles in regulating pH value, HCO3- and Cl- in the epididymal lumen. At the same time, we found the epididymal cells detached from each other ,the number of epididymal cells decreased and the structures of epithelium were disorganized in the rat model of varicocele. And the level of oxidative stress and plasmin increased , which was consistent with the severity of epididymal epithelium damage. Thus we hypothesize that "varicocele can destroy the epididymal structure by oxidative stress mediated plasmin, which causes the disorder of lumen microenvironment and reduces the sperm motility". We will study the mechanism by which oxidative stress mediated plasmin destroys the structure and function of epididymal epithelium in varicocele by Molecular Biotechnology, aiming to obtain the evidence for our hypothesis that varicocele damages epididymis epithelium by plasmin. We will elucidate the mechanism of epididymal epithelium damage in varicocele from the perspective that oxidative stress mediated plasmin destroying the connexin of epididymal cells,in order to provide sufficient scientific basis for the anti-plasmin treatment of varicocele related infertility.

精索静脉曲张(Varicocele)影响精液质量的机制既往多集中在睾丸水平，其对附睾功能、结构的影响及机制尚不完全清楚。我们前期研究系统阐述了附睾上皮细胞调节管腔pH值及HCO3-、Cl-的作用及机制，还发现精索静脉曲张大鼠附睾上皮细胞脱落、上皮结构受损，附睾组织中氧化应激、纤溶蛋白酶水平增高，并与附睾上皮受损程度一致。据此我们提出“精索静脉曲张通过氧化应激介导纤溶蛋白酶破坏上皮细胞连接蛋白，损伤附睾上皮结构，导致微环境紊乱，影响精液质量”的科学假说。本项目拟应用精索静脉曲张模型，采用分子生物学等方法，研究氧化应激介导纤溶蛋白酶损伤附睾结构与功能的机制，旨在获得精索静脉曲张通过纤溶蛋白酶损伤附睾上皮的可靠证据，从氧化应激介导纤溶蛋白酶破坏上皮细胞连接蛋白的角度阐明VC附睾上皮损伤的机制，为抗纤溶蛋白酶治疗精索静脉曲张相关不育提供充分科学依据。

本研究在前期改良的左侧精索静脉曲张大鼠模型基础上，通过检测精索静脉曲张假手术组、实验组和抗氧化剂治疗组三组大鼠附睾病理学改变、反应附睾正常功能的指标（α-葡糖苷酶含量）、附睾液精子活力、附睾组织氧化应激水平（超氧化物歧化酶 SOD、总抗氧化能力活性 T-AOC，丙二醛 MDA）以及附睾上皮细胞连接ZO-1水平的改变，发现：精索静脉曲张大鼠左侧附睾组织氧化应激水平明显升高，附睾连接蛋白中ZO-1表达明显下调，附睾上皮细胞间紧密链接结构破坏，附睾组织出现明显病理变化，附睾上皮结构紊乱，上皮细胞细胞数量减少，并可见部分上皮细胞脱落至附睾管腔，α-葡糖苷酶含量亦下降，附睾液精子活力明显下降；经维生素E抗氧化干预后，附睾组织氧化应激水平、附睾附睾连接蛋白ZO-1表达、附睾上皮细胞间紧密连接、附睾结构、α-葡糖苷酶含量以及附睾液精子活力都明显改善。得出以下研究结果：精索静脉曲张可能通过破坏附睾内氧化应激平衡，介导附睾上皮细胞间紧密连接蛋白ZO-1表达的下调，从而破坏附睾上皮细胞紧密连接，损伤附睾结构，破坏附睾正常功能，影响精子正常成熟进程，引起精子活力下降，导致男性不育的发生。抗氧化剂维生素E可以改善精索静脉曲张大鼠附睾中氧化应激平衡的失调，恢复附睾上皮细胞紧密连接的完整性，保护附睾正常结构和功能，保障精子正常成熟进程，提高精子活力，恢复男性生育力。