Aitken R J, Buckingham D, Harkiss D
MRC Reproductive Biology Unit, Edinburgh, UK.
J Reprod Fertil. 1993 Mar;97(2):441-50. doi: 10.1530/jrf.0.0970441.
The reaction between xanthine and xanthine oxidase results in the univalent and divalent reduction of dioxygen to generate superoxide (O2-.) and hydrogen peroxide (H2O2), respectively. With the aid of this system, the direct effect of reactive oxygen species (ROS) on human sperm function has been investigated. A protocol involving the addition of xanthine oxidase to the reaction mixture at 0 and 15 min resulted in a loss of motility involving every component of sperm movement examined. Lower doses of xanthine oxidase, which did not influence sperm motility, were also found to suppress the competence of human spermatozoa to exhibit oocyte fusion in response to the ionophore, A23187. The reactive oxygen species responsible for the disruption of human sperm function was not influenced by the presence of superoxide dismutase (SOD) or scavengers of hypochlorous acid or hydroxyl radicals. However, the cytotoxic species was shown to be extremely stable and could be completely eliminated by catalase, which selectively eliminates H2O2. Confirmation that it is H2O2, and not O2-., which is cytotoxic to human spermatozoa was obtained in studies in which the direct addition of this oxidant was shown to influence both the movement of human spermatozoa and their competence for oocyte fusion. These results carry implications for the diagnosis of defective sperm function and the design of optimized culture media for the treatment of male factor infertility.
黄嘌呤与黄嘌呤氧化酶之间的反应会使二价氧发生一价和二价还原，分别生成超氧化物（O2-.）和过氧化氢（H2O2）。借助该系统，研究了活性氧（ROS）对人类精子功能的直接影响。在0分钟和15分钟时向反应混合物中添加黄嘌呤氧化酶的实验方案导致所检测的精子运动各组成部分的活力丧失。还发现较低剂量的黄嘌呤氧化酶虽不影响精子活力，但会抑制人类精子对离子载体A23187作出卵母细胞融合反应的能力。负责破坏人类精子功能的活性氧不受超氧化物歧化酶（SOD）或次氯酸或羟基自由基清除剂的影响。然而，细胞毒性物质显示出极其稳定，并且可以被过氧化氢酶完全消除，过氧化氢酶可选择性地消除H2O2。在直接添加这种氧化剂被证明会影响人类精子运动及其卵母细胞融合能力的研究中，证实了对人类精子具有细胞毒性的是H2O2而非O2-.。这些结果对精子功能缺陷的诊断以及治疗男性因素不孕症的优化培养基设计具有启示意义。
