解偶联蛋白2参与人类精子抗氧化损伤的研究

目的:人类精子对氧化应激非常敏感,解偶联蛋白2(UCP2)存在于多种组织内,通过控制细胞内活性氧(ROS)水平,参与细胞抗氧化应激损伤。本研究通过观察精子UCP2表达对精子膜脂类过氧化物水平和活力的影响,探讨精子的抗氧化机制。方法:应用计算机辅助精液分析对97份精液参数检测,根据a+b级精子百分率分为4组,Ⅰ组25例:a+b级精子>50%;Ⅱ组24例:a+b级精子25%～50%;Ⅲ组24例:a+b级精子10%～25%;Ⅳ组24例:a+b级精子<10%。应用RT-PCR检测精子UCP2mRNA的表达;同时测定精子悬液中膜脂类过氧化反应产物丙二醛(MDA)含量。结果:4组精子UCP2mRNA表达水平分别为1.51±0.24、1.28±0.15、1.17±0.20、0.69±0.18,MDA含量分别为(14.66±2.55)、(16.00±2.09)、(17.44±1.40)、(21.20±3.50)nmol/108精子。UCP2mRNA表达与MDA含量呈负相关(r=-0.633,P<0.01),精子活力较低组UCP2表达显著下降(P<0.01),MDA含量显著升高(P<0.05)。结论:精子内存在UCP2-ROS调节系统,UCP2参与精子氧化还原调节,在精子抗氧化应激中起重要作用。

Uncoupling protein 2 combats oxidative damage to human sperm

Objective:Germ cells are much more susceptible to oxidative stress than somatic cells.Accumulating evidence indicates that uncoupling protein 2 (UCP2) prevents the apoptosis of multiple types of cells induced by reactive oxygen species (ROS).The present study aimed to evaluate the protective effect of uncoupling protein 2 (UCP2) against oxidative damage to human sperm.Methods:Semen parameters were obtained from 97 semen samples by computer assisted sperm analysis (CASA),and the samples,based on the percentage of grade a+b sperm,allotted to Groups Ⅰ (n = 25,grade a+b sperm >50%),Ⅱ (n = 24,grade a+b sperm 25%-50%),Ⅲ (n = 24,grade a+b sperm 10-25%) and Ⅳ (n = 24,grade a+b sperm <10%).The expressions of sperm UCP2 mRNA was detected by RT-PCR,and the malonaldehyde (MDA) content in ROS was determined in the sperm suspension.Results:The expressions of UCP2 mRNA in sperm were 1.51±0.24,1.28±0.15,1.17±0.20 and 0.69±0.18,and the MDA contents were (14.66±2.55),(16.00±2.09),(17.44±1.40) and (21.20±3.50) nmol/108 sperm in Groups Ⅰ,Ⅱ,Ⅲ and Ⅳ,respectively.There was a significant negative correlation between the expression of UCP2 mRNA and the content of MDA (r =-0.633,P <0.01),the former obviously reduced while the latter remarkably increased in the groups of lower sperm motility (P<0.01).Conclusion:UCP2 plays an important protective role against oxidative stress damage to human sperm by diminishing ROS production.