维生素E对人精子冻融氧化应激损伤的保护作用

目的:探讨水溶性维生素E(Trolox)对冻融人精子氧化应激损伤的可能保护作用及机制。方法:选取16份健康生育男性的精液标本,分析精液常规参数及动力学参数后,将每份精液一式4份,1∶1加入冷冻保护液后混匀,不含水溶性维生素E者设为阴性对照组(G0),而G1、G2、G3实验组混合液中分别含有50、100、200μmol/L浓度的水溶性维生素E,冷冻复苏精液常规分析,检测复苏后精液中活性氧(ROS)水平,采用硫巴比妥酸法(TBA)检测精子中脂质过氧化产物丙二醛(MDA)浓度。结果:冻融后各组精子运动参数较新鲜精液参数均明显下降(P0.01),G2组前向运动精子百分率[(53.33±5.63)%]较对照组[(47.85±5.09)%]明显改善(P0.05),精子VCL和VAP高于阴性对照组(P0.05)。G2组与G3组的ROS及MDA均低于阴性对照组(P0.05)。结论:在精液冷冻保护液中添加一定浓度的水溶性维生素E可以减少精子冻融过程中产生的过量ROS,减轻ROS对精子质膜的氧化应激性损伤,从而提高冻融后的精子活力。

Water-soluble vitamin E protects post-thawing sperm against oxidative stress injury

Objective： To investigate the potential protective effect of water-soluble vitamin E （Trolox） against oxidative stress injury in post-thawing human sperm and its mechanism. Methods ： Semen samples from 16 fertile men were mixed with modified cryo- protectant and each sample was equally divided into groups 0 （ G0）, 1 （ G1 ）, 2 （G2） and 3 （ G3 ） according to the concentration of Trolox measured by computer-assisted semen analysis （CASA）. GO, with no Trolox in the mixed cryoprotectant, served as the control, while G1, G2 and G3 contained 50, 100 and 200 μmol/L of Trolox, respectively. Before and after thawing, the semen samples were subjected to CASA for sperm kinematics, flow cytometry for reactive oxygen species （ROS）, and thiobarbituric acid assay for the con- centration of malondialdehyde （MDA）. Results ： After cryopreservation, sperm motility was markedly decreased in all the groups （ P 〈 0.01 ）, but less in G2 than in the control （ [ 53.33± 5.63 ] % vs [47.85 ±5.09] %, P 〈 0.05 ）. Curvilinear velocity and average path velocity were remarkably higher in G2 （ P 〈 0.05 ）, and ROS and MDA significantly lower in G2 and G3 than in the control （ P 〈 0.05）. Conclusion： Addition of vitamin E （Trolox） to freezing extender at a moderate concentration may decrease surplus ROS in the freezing-thawing process, ease ROS-induced oxidative stress injury to the plasma membrane, and improve sperm motility and kine- matic parameters after cryopreservation.