Orexin-A对大鼠脑缺血再灌注损伤的保护作用

Protective Effect of Orexin-A on the Cerebral Ischemia Reperfusion Injury in Rats

目的:研究orexin-A对缺血再灌注大鼠脑损伤的保护作用。方法:取成年雄性大鼠6只,观察MCAO前和MCAO后2 h、24h的生理学参数,界定后续指标参考时间。另取20只大鼠随机分为MCAO组、vehicle组、orexin-A 50μg/kg组和orexin-A 100μg/kg组(n=5),于缺血再灌注24 h后评估大鼠神经功能学评分和脑梗死容积。再取60只大鼠同样分成4组,(各组n=15),每组在术前、手术后6 h、24 h(各时间点n=5)取脑组织匀浆离心,检测上清液中谷胱甘肽过氧化物酶(GSH-PX)和丙二醛(MDA)的含量。结果:(1)大鼠MCAO术前、术后2 h、24 h生理参数比较无统计学意义(P>0.05),提示脑保护参考指标在MCAO后24 h内不受影响。(2)与MCAO组、vehicle组相比,orexin-A 50和100μg/kg降低神经功能评分(P<0.05)且梗死容积缩小(P<0.05);术前、术后6 h和术后24 h,脑匀浆中GSH-PX活性升高,MDA含量降低(P<0.05)。结论:Orexin-A可能通过降低脑内自由基水平,控制脂质过氧化物酶从而对脑缺血再灌注损伤起保护作用。

Objective： To evaluate the protective effect of orexin-A on the cerebral ischemia reperfusion injury in rats. Methods： The physiological parameters were observed to define time rang by six rats before MCAO and after MCAO 2 h, 24 h. Twenty rats were randomly divided into middle cerebral artery occlusion （MCAO） group, vehicle group, orexin-A 50 μg/kg and orexin-A 100 μg/kg group （n=5）. Neurological dysfunction scores （NDS） and infarct volume were measured at 24h after ischemia-reperfusion. The other sixty rats were also divided into 4 groups （n=15 each group）, the level of glutathione peroxidase （GSH-PX） and maleic diadehyde （MDA） in brain plasm were detected pre-operation and at 6 h, 24 h after ischemia-reperfusion （n=5 each time point）. Results： ONo significant differentce was found in the pyhsiological parameters of rats before MCAO and at 2 h, 24 h after MCAO （P〉0.05）, suggesting that the follow indexes of cerebral protection hadn＇t been influenced within 24 h after MCAO. ②Compared with the MCAO group and vehicle group, the NDS （P〈0.05） and the percentage of brain infarct were better in the orexin-A 50 and 100 μg/kg group （P〈0.05）; the concentration of GSH-PX was increased and MDA was decreased in orexin-A 50 and 100 μg/kg group （P〈0.05）. Conclusion： Orexin-A might play a protective role in the cerebral ischemia reperfusion injury in rats by increasing the concentration of antiperoxidase and decreasing the level of oxygen flee radicals.