基于Keap1/Nrf2/HO-1通路探讨虎杖苷对衰老小鼠学习认知障碍的作用机制

Exploration of mechanism of polydatin in learning and cognitive impairment in aging mice based on Keap1/Nrf2/HO-1 pathway

目的研究虎杖苷对D-半乳糖致衰老模型小鼠的调节作用。方法将56只ICR小鼠(雌雄各半)分为正常组、模型组、阳性组、虎杖苷低、中、高治疗组,通过每日颈后部皮下注射D-半乳糖(500 mg·kg^(-1))建立衰老模型。造模期间,阳性组灌胃盐酸多奈哌齐片(0.75 mg·kg^(-1)),治疗组灌胃虎杖苷(40、70、100 mg·kg^(-1)),正常组给予等量生理盐水。通过筑巢实验、新型物体识别实验与Morris水迷宫实验评估小鼠学习认知能力;取小鼠心、肝、脾、肾、胸腺计算脏器指数;苏木精-伊红(HE)染色观察小鼠全脑组织病理变化;ELISA检测小鼠血清与全脑组织中T-SOD、MDA、GSH-Px、AchE水平;Western blot检测小鼠海马组织Keap1、Nrf2、HO-1蛋白表达水平。结果较模型组相比,阳性组与虎杖苷低、中、高剂量组小鼠的筑巢能力、对新物体的识别能力与水下寻找站台的能力有所上升;脏器指数增加;大脑皮层与海马组织的神经元损伤明显改善;血清与脑组织中T-SOD、GSH-Px活性升高,MDA、AchE活性下降;海马组织中Nrf2、HO-1蛋白表达水平上升,Keap1蛋白表达水平降低。结论虎杖苷对D-半乳糖致衰老模型小鼠的学习认知障碍具有改善作用,其机制可能与Keap1/Nrf2/HO-1通路有关。

Aim To study the regulatory effect of polydatin on D-galactose-induced aging model mice.Methods Fifty-six ICR mice(half male and half female)were divided into normal group,model group,positive group,low,medium and high polydatin treatment groups.Aging model was established by subcutaneous injection of D-galactose(500 mg·kg^(-1))into the back of neck every day.During the modeling period,the positive group was given donepezil hydrochloride tablets(0.75 mg·kg^(-1))by gavage,the treatment group was given polydatin(40,70,100 mg·kg^(-1))by gavage,and the normal group was given the same amount of normal saline.The learning and cognitive ability of mice was evaluated by nesting experiment,new object recognition experiment and Morris water maze experiment.The heart,liver,spleen,kidney and thymus of mice were taken to calculate the organ index.The pathological changes of whole brain tissue in mice were observed by hematoxylin-eosin(HE)staining.The levels of T-SOD,MDA,GSH-Px and AchE in serum and whole brain tissue of mice were detected by ELISA.The protein expression levels of Keap1,Nrf2 and HO-1 in hippocampus of mice were detected by Western blot.Results Compared with the model group,the nesting ability,the ability to recognize new objects and the ability to find platforms underwater of the mice in the positive group and the low,medium and high dose groups of polydatin were improved.The organ index increased.The neuronal damage in the cerebral cortex and hippocampus was significantly ameliorated.The activities of T-SOD and GSH-Px in serum and brain tissue increased and the activities of MDA and AchE decreased.The expression levels of Nrf2 and HO-1 protein in hippocampus increased,and the expression level of Keap1 protein decreased.Conclusions Polydatin can ameliorate the learning and cognitive impairment in D-galactose-induced aging model mice,and its mechanism may be related to the Keap1/Nrf2/HO-1 pathway.