褪黑素在活性氧致精子线粒体功能损伤中的保护作用

目的 :探讨活性氧 (ROS)对精子线粒体功能的损伤以及褪黑素 (MLT)的保护作用。　方法 :采用Percoll梯度离心法选择具有正常生理功能的精子 ,作为本实验的正常精子模型。应用次黄嘌呤—黄嘌呤氧化酶体系产生ROS ,在MLT存在与不存在情况下 ,与精子模型分别孵育 30和 6 0min后 ,采用酶组织化学方法分析精子线粒体部位的琥珀酸脱氢酶 (SDH)活性 ,采用Rhodamine 1 2 3(Rh1 2 3)荧光探针标记精子 ,通过流式细胞仪检测线粒体膜电位。　结果 :正常精子与ROS孵育后 ,精子线粒体膜电位明显降低 ,线粒体SDH活力降低极为显著 ;而MLT则减轻了ROS对精子线粒体功能的损伤。　结论 :ROS可通过对精子线粒体膜电位和SDH活力的影响 ,而导致精子线粒体功能损伤 ;MLT可通过其有效的抗氧化能力 ,保护精子对抗ROS对其线粒体功能的损伤

Protection of Melatonin against Damage of Sperm Mitochondrial Function Induced by Reactive Oxygen Species

Objective: To study the damage of mitochondrial function of sperm induced by reactive oxygen species (ROS) , and the protection of melatonin (MLT) against the danage. Methods: Spermatozoa of normal physiological function selected from semen samples by Percoll gradient centrifugation technique were used as normal sperm models in the present study. Reactive oxygen species were generated by hypoxanthine xanthine oxidase system, and in the presence (or absence) of MLT (6 mmol/L), incubated with normal sperm models for 30 and 60 minutes. After incubation, the activity of succinate dehydrogenase(SDH) in mitochondria of spermatozoa was assessed by histochemical method,and spermatozoa were labeled with specific fluorescent probe of Rhodamine 123 to measure mitochondrial membrane potential (MMP) by flow cytometry. Results: After normal spermatozoa were incubated with ROS, MMP of spermatozoa significantly decreased, and the activity of SDH almost decreased to zero. However, MLT had effect on reducing the damage of the mitochondrial function of sperm induced by ROS. Conclusion: ROS can damage the mitochondrial function of sperm by affecting MMP of spermatozoa and the activity of SDH. MLT can protect sperm mitochondria from the damage induced by ROS through its effective antioxidative potential.