褪黑素对大鼠脑缺血时白细胞浸润和 ICAM-1表达的影响

目的研究褪黑素(melatonin,MT)对大鼠脑缺血损伤缺血区髓过氧化物酶(myeloperoxidase,MPO)的活性及细胞间黏附分子-1(intercellular adhesion molecule-1,ICAM-1)表达的影响。方法线栓法造成大鼠大脑中动脉栓塞制成脑缺血模型,手术分为正常对照组、缺血组、MT治疗组,MT治疗组缺血前30min给予MT (20mg/kg)腹腔注射。术后在相应时间点取缺血侧脑组织,用分光光度计检测MPO的活性,用免疫组化检测I- CAM-1蛋白的表达。结果与正常对照组比较,缺血组各时间点MPO的活性及ICAM-1蛋白的表达均升高,而与缺血组比较MT治疗组各时间点MPO的活性及ICAM-1蛋白的表达均降低。结论MT可能能通过降低MPO的活性即抑制白细胞的浸润和降低ICAM-1蛋白的表达,对缺血的脑组织产生保护作用。

The effects of melatonin on the activity of myelperoxidase and the expression of ICAM-1 after focal cerebral ischemia in rats

Objective To study the effects of melatonin(MT) on the activity of myeloperoxidase and the ex- pression of intercellular adhesion molecule-1 (ICAM-1) after focal cerebral ischemia in rat's ischemial area. Methods The cerebral ischemial model was established through a string inserted into the internal carotid artery to occlude middle cerebral artery.The animals were divided into 3 groups:the normal group,the ischemical group,the melatonin administrated group.Melatonin was administered via peritoneal injection (20mg/kg) 30 minute before operation.After operation,the brains were taken at different time points.Spectrophotometry and immunohis- tochemistry chemical method was used for the determination of the activity of MPO and the expression of ICAM-1 in the brain tissue respectively.Results As compared with the control group,the activity of MPO and the expres- sion of ICAM-1 were increased at all time points in ischemical group,but compared with ischemical group,the ac- tivity of MPO and the expression of ICAM-1 were decreased in melatonin administrated group.Conclusion MT could pretect the brain from ischemcal damages by decreasing MPO activity and ICAM-1 expression.