Yizhi Congming Decoction attenuates learning and memory deficits through reducing tau hyperphosphorylation in Aβ-induced AD mice / 中成药

ABSTRACT

AIM To study the effects of Yizhi Congming Decoction (Ginseng Radix et Rhizoma,Poria,Polygoni multiflori Radix praeparata,etc.) on learning and memory deficits through reducing tau hyperphosphorylation in Aβ-induced AD mice and its mechanism of action.METHODS Sixty ICR mice were randomly and equally assigned into six groups.Sham group (injection of 3 μL normal saline into left hippocampus),model group,donepezil group and each group of Yizhi Congming Decoction (injection of 3 μL Aβ25-35 into left hippocampus).Donepezil group and three treatment groups were gavaged with donepezil and Yizhi Congming Decoction.After 15 days of administration,immunohistochemistry was used to observe the expressions of Ser404 and Thr231.Western blot was performed to evaluate the levels of phosphatidylinositol-3-kinase (PI3K),threonine/serine protein kinase B (AKT) and glycogen synthase kinase 3β (GSK3β).RESULTS Yizhi Congming Decoction attenuated the levels of phosphorylated tau at the Thr231 and Ser404 sites in the hippocampus and increased the phosphorylation levels of PI3K,AKT and GSK3β.CONCLUSION Yizhi Congming Decoction effectively provides protection against learning and memory deficits and inhibits hyperphosphorylated tau protein expression in the hippocampus.The possible mechanism may occur via the PI3 K/Akt-dependent GSK3 β signalling pathway.