脑缺血损伤后细胞外信号调节蛋白激酶1/2信号通路及胡黄连苷Ⅱ的干预作用

Effect of Picroside Ⅱ on ERK1/2 signal transduction pathway in rats with cerebral ischemic injury

目的探讨胡黄连苷Ⅱ对脑缺血损伤后细胞外信号调节蛋白激酶1/2(ERK1/2)信号转导通路的影响。方法成年健康雄性Wistar大鼠90只,随机选择15只为对照组,其余75只应用线栓法建立大鼠脑缺血模型,经腹腔注射胡黄连苷Ⅱ20 mg/kg干预治疗为胡黄连苷组。将成功的60只动物模型随机分为模型组、治疗组、脂多糖(LPS)组及U0126组,每组15只。用改良神经功能缺损评分(m NSS)评价动物神经行为功能,原位末端标记法(TUNEL)检测细胞凋亡,Western blot检测ERK1/2表达水平。结果大鼠脑缺血损伤后出现神经行为功能障碍,皮质区神经细胞凋亡数量和p ERK1/2蛋白表达较对照组明显增多(P<0.05)。胡黄连苷组和U0126组大鼠皮质区凋亡细胞与p ERK1/2表达较模型组明显降低(P<0.05),LPS组大鼠凋亡细胞与p ERK1/2表达水平较高,但后期p ERK1/2表达水平有所下降,动物神经行为功能恢复。结论胡黄连苷Ⅱ可能通过降低ERK1/2磷酸化水平,抑制神经细胞凋亡。

【Objective】 To explore the effect of Picroside Ⅱ on ERK1/2 signal transduction pathway after cerebral ischemia injury in rats. 【Methods】 The focal cerebral ischemic model was established by inserting a monofilament thread into middle cerebral artery for occlusion in 90 Wistar rats. The rats in the treatment group were treated by intraperitoneal injection of Picroside Ⅱ（20 mg/kg）. The neurobehavioral function was evaluated by Modified Neurological Severity Score points test（m NSS）. The apoptotic cells were counted by terminal deoxynucleotidyl transferase d UTP nick end labeling assay. The expression of p ERK1/2 was determined by Western blot. 【Results】 After cerebral ischemia, the rats had neurological behavioral malfunction.As time progressed after cerebral ischemia, the apoptotic cells and the expression of p ERK1/2 significantly increased compared to those in the control group（P〈0.05）. The apoptotic cells and the expression of p ERK1/2in the treatment and U0126 groups were much lower than those in the model group（P〈0.05）. In the LPS 6 h subgroup the apoptotic cells and the expression of p ERK1/2 were the highest, and slightly recovered during the later period. 【Conclusion】 Picroside Ⅱ might reduce cell apoptosis by inhibiting the activation of ERK1/2 in cerebral ischemic injury.