杜仲对脑缺血大鼠神经功能保护作用及机制研究

Neuroprotective effect and mechanism of Eucommia ulmoides on cerebral ischemia rats

目的 探讨杜仲对脑缺血大鼠神经功能的保护作用及其机制。方法 将75只SD大鼠随机分为假手术组、模型组、杜仲组、3-甲基腺嘌呤组、雷帕霉素组,每组15只。假手术组分离血管但不栓塞;其余各组采用改良线栓法制备缺血再灌注模型。杜仲组造模前14 d开始给予杜仲煎剂8 g/kg灌胃,假手术组和模型组给予等体积生理盐水灌胃,均每天1次;3-甲基腺嘌呤组在造模前24 h、30 min和血流再灌注恢复时腹腔注射3-甲基腺嘌呤组30 mg/kg;雷帕霉素组在造模前24 h、造模前30 min腹腔注射雷帕霉素3 mg/kg。再灌注后24 h,对各组大鼠进行神经功能评分和认知功能评估,采用免疫组织化学法检测脑组织中Beclin-1、LC3Ⅱ蛋白表达情况。结果 再灌注后24 h,杜仲组、3-甲基腺嘌呤组大鼠神经功能评分明显低于模型组(P均<0.05),雷帕霉素组神经功能评分明显高于模型组(P<0.05);与假手术组比较,模型组和雷帕霉素组大鼠逃避潜伏期均明显延长(P均<0.05),大鼠穿越平台次数均明显减少(P均<0.05),脑组织中Beclin-1、LC3Ⅱ阳性细胞数均明显增多(P均<0.05);与模型组和雷帕霉素组比较,杜仲组、3-甲基腺嘌呤组大鼠逃避潜伏期均明显缩短(P均<0.05),大鼠穿越平台次数均明显增多(P均<0.05),脑组织中Beclin-1、LC3Ⅱ阳性细胞数均明显减少(P均<0.05)。结论 杜仲能减轻脑缺血大鼠神经功能损伤,其可能通过调节Beclin-1、LC3Ⅱ蛋白的表达抑制自噬而发挥神经保护作用。

Objective It is to investigate the protective effect of Eucommia ulmoides on neural function in rats with cerebral ischemia and its mechanism.Methods Seventy-five SD rats were randomly divided into sham operation group,model group,dulcimer group,3-methyladenine group and rapamycin group,with 15 rats in each group.The vessels of the rats were separated but not embolized in the sham operation group,ischemia-reperfusion models were prepared in the remaining groups by modified thread embolization.The Eucommia ulmoides group was given Eucommia ulmoides decoction 8 g/kg by gavage starting 14 d before modeling,and the sham operation group and model group were given equal volume of normal saline by gavage,all once a day;the 3-methyladenine group was given 3-methyladenine 30 mg/kg by intraperitoneal injection at 24 h,30 min before modeling and when blood flow reperfusion resumed;the rapamycin group was given rapamycin 3 mg/kg by intraperitoneal injection at 24h and 30min before modeling.At 24 h after reperfusion,the neurological function scores and cognitive function of the rats were assessed in each group,and the expression of Beclin-1 and LC3Ⅱproteins in brain tissue were detected by immunohistochemistry.Results At 24 h after reperfusion,the neurological function scores of the rats in the Eucommia ulmoides group and 3-methyladenine group were significantly lower than those in the model group(all P<0.05),and the neurological function scores in the rapamycin group were significantly higher than that in the model group(P<0.05).Compared with the sham operation group,the escape latency of the rats in the model group and rapamycin group was significantly prolonged(both P<0.05),the times of cross ing the platform were significantly reduced(all P<0.05),and the number of Beclin-1 and LC3Ⅱpositive cells in brain tissue were significantly increased(all P<0.05).Compared with the model group and rapamycin group,the escape latency of the rats in the Eucommia ulmoides group and 3-methyladenine group was significantly shortened(both P<0.05),the times of crossing the platform were significantly increased(all P<0.05),and the number of Beclin-1 and LC3Ⅱpositive cells in brain tissue were significantly decreased(all P<0.05).Conclusion Eucommia ulmoides can alleviate neurological damage in rats with cerebral ischemia,which may plays neuroprotective effects by regulating the expression of Beclin-1 and LC3Ⅱproteins to inhibite autophagy.