褪黑素对脑缺血再灌注后脑内抗氧化酶及MDA的影响

目的　研究褪黑素 (melatonin ,MT)对脑缺血再灌注沙土鼠脑组织谷胱甘肽过氧化物酶 (GPx)、超氧化物歧化酶(SOD)活性及丙二醛 (MDA)含量的影响 ,探讨MT的脑保护作用机制。方法　采用沙土鼠双侧颈总动脉结扎法制作前脑缺血再灌注损伤的模型 ,缺血前 30min腹腔注射MT ,测定脑缺血再灌注 1h沙土鼠大脑皮层和纹状体GPx、SOD活性及MDA含量。结果　脑缺血再灌注后大脑皮层和纹状体GPx、SOD活性降低 ,MDA含量升高 ;MT预处理能部分反转这种变化。结论　MT对脑缺血再灌注损伤有保护作用 ,其机制可能与保护GPx、SOD活性 ,减少脂质过氧化有关

Effects of melatonin on some antioxidant enzymes and MDA in brain of global ischemic gerbils

AIM To investigate the effects of melatonin (MT) on glutathione peroxidase(GPx), superoxide dismutase(SOD) activities and malondialdehyde(MDA) contents in the cerebrum of cerebral ischemia-reperfusion gerbils, so as to explore the protective mechanisms of MT. METHODS Cerebral ischemia-reperfusion model was made by 10 min occlusion of bilateral carotid arteries of gerbil. MT was administered intraperitoneally 30 min prior to the onset of ischemia. After 1 h reperfusion, bilateral cortex and striatum were taken out for measurement of GPx, SOD and MDA. RESULTS Ischemia-reperfusion lowered the activities of GPx and SOD in cerebral cortex and striatum. Conversely, it elevated the contents of MDA in both areas. Treatment with MT at 5, 10, or 20 mg·kg -1 partly reversed these effects. CONCLUSION MT provides protective effect against cerebral ischemia-reperfusion injury by protecting GPx and SOD activities and reducing the lipid peroxidation.