从Notch通路探讨电针促进局灶性脑缺血再灌注大鼠海马神经干细胞增殖的作用机制

关键词：电针  脑缺血  Notch通路  神经干细胞  增殖

Keywords:electroacupuncture  cerebral ischemia  Notch  neural stem cell  proliferation

摘要：

      摘要 目的：通过Notch信号通路探讨电针对局灶性脑缺血再灌注模型大鼠海马神经干细胞增殖的促进作用，阐明其治疗脑梗死的可能机制。 方法：将54只SD大鼠随机分为假手术组、模型组及电针组，以大脑中动脉闭塞（MCAO）法建立大鼠局灶性脑缺血再灌注模型，通过巢蛋白（nestin）免疫组化法观察脑缺血大鼠海马神经干细胞增殖情况，应用蛋白免疫印迹法（Western blot）和RT-PCR检测海马组织中Notch信号通路上关键信号分子Notch1和胞内片段（NICD）的表达情况，同时使用酶联免疫吸附法（ELISA）测定大鼠血清中血管内皮生长因子（VEGF）浓度。 结果：电针“曲池”、“足三里”穴可明显改善MCAO大鼠的神经功能缺损症状；促进脑缺血后海马神经干细胞（nestin+）的增殖（模型组 vs 电针组：173.40±38.76 vs 246.80±47.73， P=0.028）；增强Notch信号通路中Notch1和NICD的表达，并提高血清中VEGF的分泌。 结论：电针可通过活化Notch信号通路，同时促进VEGF的分泌，促进海马神经干细胞的增殖，来实现对脑缺血的治疗作用。

Abstract:

      Abstract Objective: To investigate the effect of electroacupuncture (EA) promoting hippocampal neural stem cells（NSCs） proliferation in rats with focal cerebral ischemia-reperfusion (I/R) via Notch pathway and to clarify the possible mechanism of EA in treatment of cerebral ischemia. Method: Fifty-four male adult SD rats were randomly divided into the sham operation control group (SC group), the ischemia model group (IC group) and the electroacupuncture group (EA group). Middle cerebral artery occlusion (MCAO) was performed to establish the focal cerebral I/R injury model. Proliferation of hippocampal NSCs in cerebral I/R injured rats was determined by nestin immunohistochemical staining. The expressions of Notch1 and intracellular domain of Notch（NICD） were detected by Western blotting and RT-PCR. The serum level of vascular endothelial growth factor (VEGF) was measured using enzyme-linked immunosorbent assay (ELISA). Result: EA at Quchi (LI11) and Zusanli (ST36) acupoints alleviated neurological deficits significantly and promoted the proliferation of hippocampal NSCs (IC vs EA: 173.40±38.76 vs 246.80±47.73, P=0.028) in cerebral I/R injured rats; enhanced the expressions of Notch1 and NICD, crucial signaling molecules in Notch signaling pathway, and increased the secretion of VEGF. Conclusion: The up-regulatory effect of EA on Notch signaling pathway and neurotrophic factor secretion may result in the promotion of NSCs proliferation and consequently provide the therapeutic effect on cerebral ischemia.