不同浓度白藜芦醇对脑缺血-再灌注大鼠HSP20表达的影响

摘要

目的 探讨不同浓度白藜芦醇对缺血-再灌注脑损伤大鼠神经功能损伤及热休克蛋白20(HSP20)表达的影响.方法 将150只健康的成年雄性SD大鼠随机分成五组:假手术组,模型组(I/R组),小剂量白藜芦醇(2.5 mg/kg)组,中剂量白藜芦醇(5 mg/kg)组,大剂量白藜芦醇(10 mg/kg)组,每组30只,制作脑缺血-再灌注大鼠模型,灌注前20 min给予生理盐水或不同浓度白藜芦醇腹腔注射,术后6h、24 h、48 h、72 h、7d时间节点分别评定神经功能缺损评分.应用四氮唑红染色(TTC)脑组织后计算脑梗死病灶体积并比较五组的差异;分别应用免疫组织化学染色和Western blot检测缺血脑组织周边区组织的HSP20表达量并比较五组的差异.结果 ①各组神经功能缺损评分比较:各模型组大鼠在缺血-再灌注后各时间节点均有神经功能缺损,同时白藜芦醇剂量越大,大鼠的神经功能缺损改善越明显;②各组脑梗死病灶体积比较:不同浓度白藜芦醇干预各组大鼠的脑梗死体积显著减少(P＜0.05),且白藜芦醇剂量越大,大鼠的脑梗死体积减少程度越大,呈显著剂量依赖性;③在各个时间点,各组大鼠缺血周边区脑组织的HSP20阳性细胞数为:大剂量白藜芦醇组＞中剂量白藜芦醇组＞小剂量白藜芦醇组＞模型组＞假手术组(P＜0.05),并且白藜芦醇剂量越大,大鼠的HSP20蛋白表达量越多.结论 ①缺血-再灌注脑损伤过程中,白藜芦醇能有效地保护大鼠脑神经细胞,减少脑梗死体积,改善神经功能缺损评分,这一作用可能是通过促进HSP20表达来完成的;②白藜芦醇对脑缺血-再灌注损伤的保护作用与剂量相关,并且呈现显著剂量依赖性.%Objective To explore the role and mechanism of different concentrations of resveratrol in the neurological function and the expression of HSP20 of cerebrally injured rats with ischemia-reperfusion.Methods We divided 150 healthy adult male SD rats by random number table into 5 groups:sham operation group,model group,low dose resveratrol (2.5 mg/kg) group,middle dose resveratrol (5 mg/kg) group,high dose resveratrol (10 mg/kg) group,with 30 rats in each group.MCAO surgery was performed in the rats to establish cerebral ischemia reperfusion model.Normal saline or different concentrations of resveratrol were intraperitoneally injected 20 minutes before the reperfusion.Neurological deficit scores were evaluated 6 h,24 h,48 h,72 h,and 7 d after the operation.Cerebral infarction volume was calculated and compared among the five groups after TTC staining of brain tissues;tumor necrosis factor HSP20 around the area of ischemia brain tissues was detected by immunohistochemistry,and compared among the five groups.Results ①Comparison of neurological deficit scores:The intervention of different concentrations of resveratrol significantly improved the neurological deficit of rats,meanwhile,the higher the dose of resveratrol was,the more obvious the improvement of rats' neurological deficit has got,which meant the improvement of high dose resveratrol group ＞ middle dose resveratrol group ＞ low dose resveratrol group (P ＜ 0.05),and it was in a dose-dependent manner.② Comparison of cerebral infarction focus volumes:The intervention of different concentrations of resveratrol significantly reduced the cerebral infarction volumes of rats in different groups (P ＜ 0.05),and the higher the dose of resveratrol was,the larger the volume of reduced cerebral infarction was,which meant the reduced cerebral infarction volume of high dose resveratrol group ＞ middle dose resveratrol group ＞ low dose resveratrol group (P ＜ 0.05),and it was in a dose-dependent manner.③Comparison of immunohistochemistry and western blots of tissues surrounding the cerebral ischemia areas:At different hours,the numbers of HSP20 positive cells in the brain tissues surrounding the rats' cerebral ischemia area were:high dose resveratrol group ＞ middle dose resveratrol group ＞ low dose resveratrol group ＞ model group ＞ sham operation group (P ＜ 0.05),and the higher the dose of resveratrol was,the larger the number of HSP20 positive cells were (P ＜ 0.05),which was in a dose-dependent manner.The higher the dose of resveratrol was,the larger the expression quantity of HSP20 were (P ＜ 0.05),which was in a dose-dependent manner.Conclusion ① In the process of cerebral ischemia-reperfusion injury,resveratrol can reduce cerebral infarction volume and improve neurological deficit scores in a dose-dependent manner.It can also promote the expression of HSP20 through some kind of mechanism.② The protective effect of resveratrol on cerebral ischemia reperfusion injury shows a significant dose-dependent manner.