山茱萸新苷经GFRα1/Ret信号通路对慢性脑低灌注大鼠认知功能障碍的改善作用

Improving Effect of Cornuside on Cognitive Dysfunction in Chronic Cerebral Hypoperfusion Rats via GFRα1/Ret Signaling Pathway

目的:探讨山茱萸新苷经胶质细胞源性神经营养因子受体α1(GFRα1)/受体酪氨酸激酶(Ret)信号通路对慢性脑低灌注大鼠认知功能障碍的改善作用。方法:50只SD大鼠采用随机数字表法分为5组:假手术组、模型组、阳性对照组(石杉碱甲,250μg·kg-1)、山茱萸新苷低、高剂量组(67.5,270 mg·kg-1),每组10只。除假手术组外,其余各组采用双侧颈总动脉闭塞(BCCAO)法制作慢性脑低灌注大鼠模型。造模成功后,山茱萸新苷低、高剂量组和阳性对照组分别灌胃给予相应药物,假手术组和模型组给予等量生理盐水,1次/d,持续给予21 d。给药结束后,进行Morris水迷宫实验;HE染色观察大鼠海马组织病理学改变;检测海马组织中胶质细胞源神经营养因子(GDNF)、GFRα1、Ret、磷酸化-Akt(p-Akt)、B细胞淋巴瘤白血病-2(Bcl-2)和Bcl-2相关X蛋白(Bax)水平。结果:模型组大鼠海马区细胞结构疏松,海马萎缩、神经元变性坏死;与模型组相比,山茱萸新苷各剂量组和阳性对照组大鼠海马区细胞结构和神经元形态得以修复,神经元变性坏死现象得到改善。与假手术组比较,模型组大鼠目标象限游泳时间、平均游泳速度、GDNF、GFRα1、Ret、p-Akt和Bcl-2水平降低,Bax水平增加(P<0.05);与模型组比较,山茱萸新苷各剂量组和阳性对照组大鼠目标象限游泳时间、平均游泳速度、GDNF、GFRα1、Ret、p-Akt和Bcl-2水平增加,Bax水平降低(P<0.05),且山茱萸新苷高、低剂量组及阳性对照组间差异有统计学意义(P<0.05)。结论:山茱萸新苷对慢性脑低灌注大鼠认知功能障碍有改善作用,其机制可能与GFRα1/Ret信号通路的激活有关。

Objective: To investigate the improving effect of cornuside on cognitive dysfunction in chronic cerebral hypoperfusion rats via GFRα1/Ret signaling pathway. Methods: Totally 50 SD rats were divided into 5 groups with random number table method:sham operation group,model group,positive control group(huperzine A,250 μg·kg-1),low and high dose cornoside groups(67.5 and 270 mg·kg-1) with 10 rats per group. Except the sham operation group,the other groups used bilateral common carotid artery occlusion(BCCAO) to make chronic cerebral hypoperfusion rat models. After successful modeling,the low and high dose cornoside groups and the positive control group were given corresponding drug by gavage. The sham operation group and the model group were given the same amount of normal saline once daily for 21 d. After the administration,Morris water maze experiment was performed;the histopathological changes of rat hippocampus were observed by HE staining;GDNF,GFRα1,Ret,p-Akt,Bcl-2 and Bax in hippocampus were detected.Results: The hippocampal cell structure in the model group was loose with hippocampus atrophy,and neuron degeneration and necrosis. Compared with those in the model group,the cell structure and neuron morphology of hippocampus in each cornoside dose group and the positive control group were repaired,and the nerves metadegeneration and necrosis were improved. Compared with those in the sham operation group,the target quadrant swimming time,average swimming speed,levels of GDNF,GFRα1,Ret,p-Akt and Bcl-2 were decreased,and the level of Bax increased(P< 0.05). Compared with those in the the model group,the target quadrant swimming time,average swimming speed,levels of GDNF,GFRα1,Ret,p-Akt and Bcl-2 were increased,and the level of Bax decreased in cornoside groups and the positive control group(P<0.05). There were statistically significant differences between cornoside groups and the positive control group(P<0.05).Conclusion: Cornuside can improve cognitive dysfunction in CHH rats,and its mechanism may be related to the activation of GFRα1/Ret signaling pathway.