脑源性神经营养因子修饰的神经干细胞移植对阿尔茨海默病大鼠的学习及p75表达的影响

The transplantation effect of neuronal stem cells modified by brain derived neurotrophic factor on the behaviors and p75 expression of Alzheimer's disease rats

目的研究脑源性神经营养因子(BDNF)修饰的神经干细胞(NSC)移植对阿尔茨海默病大鼠的学习及p75表达的影响。方法 36只SD成年大鼠被选为受试对象。采用Aβ1-40立体定向注射法制作阿尔茨海默病模型(AD),并将AD模型大鼠随机分为3组:BDNF修饰的神经干细胞(BDNF-NSC)移植组、神经干细胞移(NSC)植组和溶剂(Vehicle)对照组(n=6),然后分别向这3组大鼠的海马区注入500μl的BDNF-NSC悬液(5×105)、NSC悬液(5×105)和相同剂量的不含细胞的培养基。注射4w后,采用Y迷宫方法检测AD大鼠的空间学习和记忆能力,随之用过量麻醉的方法处死受试大鼠,立即取脑并分别采用免疫组织化学方法检测BDNF-NSC在海马区的表达和Western blot法检测p75蛋白在海马区的表达。结果 BDNF-NSC组大鼠的行为学能力较NSC组和Vehi-cle组明显提高(P<0.05),同时免疫组化检测显示在海马区的BDNF-NSC阳性细胞数明显增多而Western blot检测显示p75蛋白在该区的表达显著降低(P<0.05)。结论 BDNF修饰的神经干细胞能够通过抑制海马区p75表达来防止由Aβ1-40造成的神经损害。

Objective To investigate the transplantation effect of neuronal stem cells modified by brain derived neurotrophic factor（BDNF-NSC） on the behaviors and p75 expression of Alzheimer＇s disease rats.Methods Thirty six male adult Sprague-Dawley rats were selected as subjects.Alzheimer＇s disease model（AD） was made through stereotactic injection of Aβ1-40 into rats＇ brain.Consequently,AD rats were divided randomly into 3 groups：BDNF-NSC,neural stem cells（NSC） and vehicle group.The rats＇ cerebral hippocampus of the 3 groups was injected by 500μl BDNF-NSC and NSC suspension（5×105） and the same dose of medium without cells respectively.After 4 weeks of treatment,Y water maze test was employed to evaluate the spatial learning and memory ability of the AD rats and then the AD rats received evaluation was sacrificed by over anesthesia.The brains of AD rats were disassociated to detect the number of BDNF-NSC positive cells by immunohistochemistry,and the expression of p75 protein by western blot within hippocampus.Results AD rats treated with BDNF-NSC had better outcome of Y water maze than the rats treated with NSC or vehicle（P0.05）.Meanwhile,the number of BDNF-NSC positive cells within hippocampus of BDNF-NSC treated rats remarkably enhanced while the expression of p75 proteins in the area significantly decreased compared with that of AD rats treated with NSC or vehicle（P0.05）.Conclusion BDNF-NSC can protect neurons against the impairment induced by AD through inhibition of the p75 expression within hippocampus.