远志皂苷元调控tau蛋白磷酸化的实验研究

Experimental Study of Tenuigenin Regulating Phosphorylation of Tau Protein

目的观察远志皂苷元对阿尔茨海默(AD)大鼠模型海马tau蛋白磷酸化相关酶类表达的影响,并探讨其机理。方法清洁级SD雄性大鼠60只,随机分为对照组、模型组、多奈哌齐组及远志皂苷元低、中、高剂量组,每组10只。侧脑室注射寡聚体形式的β淀粉样蛋白(Aβ)1-42制备AD大鼠模型,术后给药组给予不同剂量远志皂苷元和多奈哌齐灌胃,对照组和AD模型组给予等量生理盐水灌胃。应用免疫组织化学方法和蛋白印迹法检测海马tau蛋白激酶(GSK-3β、CDK-5)和磷酸酯酶(PP-1、PP-2A)的表达水平。结果与对照组比较,模型组tau蛋白激酶表达明显升高,磷酸酯酶表达明显降低(P<0.01);与模型组比较,远志皂苷元各剂量组蛋白激酶表达明显降低,磷酸酯酶表达明显升高(P<0.01)。结论远志皂苷元能调节AD大鼠模型蛋白激酶和磷酸酯酶之间的平衡失调。

Objective To study the enzymes related to phosphorylation of tau proteins in AD rats, observe the effect of tenuigenin on the changes and explore its mechanism. Methods Sixty SD cleaning laboratory rats were randomly divided into six groups., control group, model group, donepezil group and low-, medium-, high-dose of tenuigenin groups. The animal model was established by Aβ1-42 stereotactic injection into lateral cerebral ventricle of rats. Tenuigenin groups were treated with gastric perfusion of tenuigenin in three different dosages, and donepezil group with donepezil. The model group and control group were given normal saline. Tissue specimens of each group were removed from the hippocampus CA1 area. Glycogen synthase kinase 3β （GSK-3β）, Cyclin-dependent kinase-5 （CDK-5） protein phosphatase-1 （PP-1）, and protein phosphatase-2A （PP-2A） were detected with immunohistochemistry and Western blot. Results The hippocampal neurons of AD rats showed significant intraceUular increase in the tau phosphokinase （GSK-3β and CDK-5） and decrease in the tau dephosphrylating enzymes （PP-1 and PP-2A）. Tenuigenin can restore the expression of enzymes to normal levels, and there was no difference between the donepezil group and tenuigenin groups. Conclusions Brain tissue of AD rats shows changes of enzymes related to phosphorylation of tau protein, and tenuigenin can ameliorate the abnormalities of AD rats.