牡荆苷对急性脑缺血大鼠大脑纹状皮质nNOS免疫表达的影响

Effect of vitexin on nNOS immune expression in striate cortex of brain in rats with acute cerebral ischemia

目的:探讨牡荆苷对急性脑缺血大鼠大脑纹状皮质神经元型一氧化氮合酶(nNOS)表达的影响。方法:建立急性脑缺血模型,假手术组和模型组均给予0.01 ml/g生理盐水腹腔注射,低、中、高剂量组分别给予1.62、3.24、6.48μmol/kg牡荆苷溶于0.01 ml/g生理盐水中腹腔注射。神经行为学评分表评价各组干预前后神经行为学变化;TTC法检测各组脑梗死体积;TUNLE检测脑梗死组织缺血性神经元细胞凋亡情况;ABC免疫组化法检测大脑纹状皮质nNOS免疫阳性神经元并对其进行定性和定量分析;以qRT-PCR检测大脑纹状皮质组织nNOS mRNA表达;以Western blot法检测大脑纹状皮质组织nNOS蛋白表达。结果:假手术组无神经行为学异常,模型组干预后神经行为学严重异常,牡荆苷剂量组较干预前以及模型组比较,均显著改善,且高剂量的牡荆苷作用效果最佳;假手术组无梗死灶,给予牡荆苷处理可减小脑梗死体积,降低缺血性神经元细胞凋亡率,还可增强大脑纹状皮质nNOS免疫阳性神经元表达,提高其IOD值、mRNA及蛋白表达,且高剂量的牡荆苷作用效果最佳。结论:牡荆苷可改善急性脑缺血大鼠的神经行为学,减小梗死灶,降低缺血性神经元细胞凋亡率,且呈剂量依赖性,可能与抑制大脑纹状皮质nNOS免疫表达,下调组织nNOS mRNA及蛋白表达有关。

Objective:To investigate the effect of vitexin on neuronal nitric oxide synthase(nNOS)immunoactivity in striatum of cerebral cortex in rats with acute cerebral ischemia.Methods:Acute cerebral ischemia models were established.Sham operation group and model group were given intraperitoneal injection of 0.01 ml/g body weight saline.Low,medium and high dose groups were given vitexin 1.62,3.24 and 6.48μmol/kg dissolved in 0.01 ml/g body weight saline intraperitoneally.The neurobehavioral changes before and after intervention were evaluated by Neurobehavioral Scale.The volume of cerebral infarction was measured by TTC method,and the apoptosis of ischemic neurons in cerebral infarction tissues was detected by TUNLE.The nNOS immunoreactive neurons in the striatum of cerebral cortex were detected by ABC immunohistochemical method and analyzed qualitatively and quantitatively.The expression of nNOS mRNA in the striatum of cerebral cortex was detected by qRT-PCR.Western blot was used to detect the expression of nNOS protein in striatum of cerebral cortex.Results:There was no neurobehavioral abnormality in the sham operation group,and the neurobehavioral abnormality was serious in the model group after intervention.The effect of vitexin group was better than that before intervention and in the model group,and the effect of vitexin 6.48μmol/kg was the best.In the sham operated group,vitexin treatment could reduce the volume of cerebral infarction and the apoptotic rate of ischemic neurons.It could also enhance the expression of nNOS immunoreactive neurons in the striate cortex of the brain,increase the IOD value,the expression of mRNA and protein.The effect of high dose vitexin group was the best.Conclusion:Vitexin can improve neurobehavioral and reduce infarct area and and the apoptotic rate of ischemic neurons in rats with acute cerebral ischemia in a dose-dependent manner.It is presumed that vitexin may be related to inhibiting the nNOS immune expression in striate areas of cerebral cortex and down-regulating the expression of nNOS protein in tissues.