AQP5在人精子超低温冻融中作用及机制研究

水通道蛋白（aquaporin, AQP）主要调节细胞中水分的平衡，而水分在细胞内转出或转入的速率是决定细胞冻融后质量的关键。课题组前期研究证实AQP5蛋白特异性表达于人精子尾部中段，精子与冷冻保护剂混合后，AQP5定位发生改变，且耐冻精子中AQP5表达显著高于不耐冻精子。而AQP5在人精子冻融中的作用及机制至今知之甚少。本研究设想AQP5在精子冻融中的渗透调节作用可以增加精子的耐低温性。为证实此假说，本研究拟明确人精子中AQP5在不同类型保护剂中的时空表达特征，分析阻断AQP5对精子冻融前后膜完整性、线粒体和顶体功能的影响，揭示AQP5在精子冻融中的作用；阐释AQP5在人精子冻融中的偶联信号转导通路，并应用AQP5基因敲除小鼠验证。本研究将有助于揭示AQP5在精子冻融中的调控新机制，为阐明精液冻融导致的精子冷冻损伤提供实验依据，从而进一步改善精子冻融技术，为男性生育力保存研究提供新靶标。

Aquaporin (AQP) mainly regulates the balance of water in cells, and the rate of water transfer in and out of cells is the key to determine the quality of cells after freezing and thawing. Previous studies of our group confirmed that AQP5 protein was specifically expressed in the middle part of the tail of human spermatozoa. After the sperm was mixed with cryoprotectant, the location of AQP5 changed, and the expression of AQP5 in freeze-resistant sperm was significantly higher than that in non-freeze-resistant sperm. However, little is known about the role and mechanism of AQP5 in human sperm freezing and thawing. This study assumes that the osmotic regulation of AQP5 in sperm freezing and thawing can increase the hypothermia tolerance of spermatozoa.In order to confirm this hypothesis, the purposes of this study are to clarify the temporal and spatial expression characteristics of AQP5 in human sperm using different types of cryoprotectant, to analyze the effects of blocking AQP5 on membrane integrity, mitochondrial and acrosome function before freezing and after thawing, consequently revealing the role of AQP5 in sperm freezing and thawing, to explain the coupled signal transduction pathway of AQP5 in human sperm freezing and thawing, which was verified by AQP5 knockout mice. This study will help to reveal the new regulatory mechanism of AQP5 in sperm freezing and thawing, and provide experimental basis for elucidating sperm freezing damage caused by semen freezing and thawing, so as to further improve sperm freezing and thawing techniques and provide a new target for the study of male fertility preservation.