线粒体呼吸功能与精子活力、核DNA损伤的相关性分析

Analysis of Mitochondria Respiratory Function Associated with Motility of Sperm and Nucleus DNA Damage

为探讨线粒体呼吸功能与精子活力、核DNA损伤程度之间的相关性,按WHO标准收集34例不同活力的精液标本,采用蔗糖差速离心法或密度梯度离心法提取精子线粒体,通过铂氧电极–溶氧仪测定线粒体呼吸耗氧率并计算状态III呼吸、状态IV呼吸、呼吸控制率(RCR)、磷氧比(P/O)及氧化磷酸化效率(OPR);应用精子染色质扩散(sperm chromatin dispersion,SCD)实验检测精子DNA损伤情况。结果表明:不同活力精子线粒体状态III呼吸耗氧量之间具有显著差异(P<0.01);弱精子症组RCR和OPR与正常对照组比较,分别降低了17.03%(P<0.05)和40.74%(P<0.01);精子DNA损伤程度与精子活力、状态III呼吸及OPR均呈极显著负相关(r值分别是-0.812、-0.788和-0.696)。以上结果提示:精子线粒体呼吸耗氧和氧化磷酸化功能与精子活力之间存在着密切的联系;精子DNA(包括mtDNA)损伤可能影响精子的正常功能。

The aim of this study is to investigate the correlationship between mitochondrial respiratory function and sperm motility and nuclear DNA damage. Thirty-four semen samples were collected according to the WHO motility criteria. The mitochondria of sperm were extracted by differential centrifugation or density gradient centrifugation. Oxygen electrode units were used to measure the respiration rate of sperm mitochondria, and calcu-late mitochondrial state III respiration（ST Ⅲ）, mitochondrial state IV respiration（ST IV）, P/O ratio, respiratory con- trol rate（RCR） and the rate of oxidative phosphorylation（OPR）. Sperm DNA damage was assessed by sperm chro- matin dispersion（SCD）. Our results showed that mitochondrial state III respiration significantly different amonggroups with different motility sperm（P〈0.01）, the RCR and OPR in asthenospermia（AST） group were significantly lower than that of control group, decreased by 17.03%（P〈0.05） and 40.74%（P〈0.001）, respectively. Linear regres- sion analysis indicated sperm DNA damage negative correlation to motility of sperm, STIII, OPR（r=-0.812, -0.788and -0.696, respectively）. In conclusion, mitochondria respiratory and oxidative phosphorylation might have close correlation with sperm motility; sperm function might be impaired when DNA was damaged.