Experimental Study of Tenuigenin Regulating Phosphorylation of Tau Protein

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 intracellular 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.