HGF对脑缺血/再灌注大鼠脑iNOS,NO及IL-1β的影响

Influence of hepatocyte growth factor on iNOS,NO and IL-1β in the cerebrum during cerebral ischemia/reperfusion in rats

目的:探讨肝细胞生长因子(HGF)对脑缺血/再灌注(I/R)大鼠脑诱导型一氧化氮合酶(iNOS)、NO及白细胞介素-1β(IL-1β)的影响。方法:SD大鼠随机分为以下5组:假手术组(Sham组);I/R组;HGF1,HGF2,HGF3组,即I/R大鼠分别注射15,30,60μg/kg HGF。线栓法建立局灶性脑I/R模型,脑缺血1.5 h再灌注24 h后,测定缺血区脑组织iNOS活性及NO含量,检测iNOS及IL-1βmRNA水平的变化,测定iNOS蛋白表达水平及IL-1β含量。另取体外培养的大鼠大脑皮层神经元行I/R处理,检测iNOS和IL-1β蛋白表达水平及NO含量。结果:大鼠缺血区脑组织iNOS活性升高、NO含量增加,iNOS和IL-1βmRNA表达上调,iNOS蛋白表达增多,IL-1β含量增加。注射不同剂量HGF均能降低缺血区脑组织iNOS活性及NO含量,下调iNOS和IL-1βmRNA的表达,抑制iNOS蛋白的表达,降低IL-1β含量。此外,HGF可明显下调体外I/R神经元IL-1β和iNOS蛋白的表达,降低NO含量。结论:抑制IL-1β的表达,减少iNOS的表达,降低NO含量可能是HGF减轻脑缺血损伤的机制之一。

Objective:To explore the effect of hepatocyte growth factor(HGF) on inducible nitric oxide synthase(iNOS),NO and interleukin-1β(IL-1β) in the cerebrum of rats subjected to cerebral ischemia/reperfusion(I/R).Methods:Sprague-Dawley rats were randomly divided into 5 groups:a sham group,an I/R group,an HGF1 group,an HGF2 group,and an HGF3 group.The latter 3 groups were respectively injected 15,30 and 60 μg/kg HGF.The focal cerebral I/R model was established by sutureoccluded method.After 1.5 h ischemia followed by 24 h reperfusion,the iNOS activity and NO content in the ischemic cerebral tissue were assessed.The expression of iNOS mRNA and IL-1β mRNA was detected.The level of iNOS protein and IL-1β content were determined.In addition,cultured cerebral cortical neurons in vitro were exposed to I/R.Then the expression of iNOS and IL-1β protein in the neurons was detected,and NO content was assessed.Results:The iNOS activity and NO content in the ischemic cerebral tissue were increased.The expression of iNOS mRNA and IL-1β mRNA was upregulated.The level of iNOS protein and IL-1β content were increased.Administration of HGF decreased the iNOS activity and NO content,and downregulated the expression of iNOS mRNA,IL-1β mRNA,iNOS protein and IL-1β content in the ischemic cerebral tissue.HGF decreased the expression of IL-1β,iNOS protein and NO content in the cortical neurons exposed to I/R in vitro.Conclusion:HGF can inhibit the expression of IL-1β and decrease the expression of iNOS and content of NO,which is probably one of the mechanisms mediating the protection of HGF against cerebral ischemia injury.