BQ-123对蛛网膜下腔出血大鼠神经功能的保护作用研究

Protective effect of BQ-123 on neural function of rats with subarachnoid hemorrhage

目的探讨BQ-123对蛛网膜下腔出血(SAH)的治疗作用及其机制。方法 160只雄性SD大鼠,随机分为假手术(Sham)组、SAH组、雷帕霉素组、低剂量BQ-123组、高剂量BQ-123组。2次注血法复制SAH大鼠模型;光镜观察海马区形态结构变化;免疫组织化学法检测海马区雷帕霉素靶蛋白(mTOR)、自噬相关基因Beclin-1和微管相关蛋白1轻链(LC3)-Ⅱ的表达;实时逆转录聚合酶链反应(real-time RT-PCR)检测mTOR、Beclin-1和LC3的mRNA表达;抓力测定实验评价各时间点大鼠前肢拉力情况;穿梭箱实验测试动物的学习功能。结果与Sham组比较,SAH组海马区mTOR、Beclin-1和LC3 mRNA表达增加,存活神经元细胞数量减少,大鼠的学习功能和拉力值下降,差异有统计学意义(P<0.05);与SAH组比较,雷帕霉素组海马区mTOR mRNA表达降低、Beclin-1和LC3 mRNA表达增高,存活神经元细胞数量增多,大鼠的学习功能和拉力值改善,差异有统计学意义(P<0.05);与SAH组比较,BQ-123组海马区mTOR mRNA降低、Beclin-1和LC3 mRNA表达增高,存活神经元细胞数量增多,动物学习功能指标和拉力值改善,差异有统计学意义(P<0.05),且上述变化在高剂量BQ-123更为明显。结论 BQ-123可改善SAH大鼠神经功能缺陷,抑制mTOR激活,从而提高海马区神经细胞自噬程度。

To investigate the therapeutical effect of BQ-123 on subarachnoid hemorrhage(SAH)in rats,and explore the mechanisms.Methods Totally 160 male SD rats were divided into 5 groups:sham operation(sham)group,SAH group,Rapamycin group,low-dosage and high-dosage BQ-123 groups.The animal models were established by injecting the autologous blood into cisterna magna twice.Optical microscopy was used to observe the morphological changes of neurons in the hippocampi at each time point.The expressions of mTOR,Beclin-1 and LC3-II proteins in the hippocampi of the rats were detected with immunohistochemistry.RT-PCR was used to detect the mRNA expressions of mammalian target of Rapamycin(mTOR),Beclin-1 and LC3.The grip experiment was used to evaluate the forelimb grip of the rats at each time point and the shuttle-box experiment was used to evaluate the ability of learning.Results Compared with the sham group,the expressions of mTOR,Beclin-1 and LC3 mRNAs increased and the number of alive nerve cells descreased in the hippocampi,the measured grip scores and the ability of learning significantly declined in the SAH group(P<0.05).Compared with the SAH group,the expression of mTOR mRNA in the hippocampi decreased,the expressions of Beclin-1 mRNA and LC3 mRNA in the hippocampi increased,and the number of alive neurons increased,and the measured grip scores and the ability of learning increased in the Rapamycin group(P<0.05).The expression of mTOR mRNA in the hippocampi decreased,the expressions of Beclin-1 mRNA and LC3 mRNA in the hippocampi and the number of alive nerve cells increased,the measured grip scores and the ability of learning also increased in the BQ-123 group(P<0.05).Conclusions BQ-123 can improve neurological function after subarachnoid hemorrhage in rats,which is related to inhibition of mTOR activation and increase of neuron autophagy in the hippocampi.