Effects of Yizhicongming decoction on Tau protein in mice with Alzheimer’s disease induced by β-amyloid (Aβ_25-35)

  Objective  To investigate the effects of Yizhicongming decoction on Tau protein hyperphosphorylation in mice with β-amyloid (Aβ_25-35)-induced Alzheimer’s disease.

  Methods  Sixty mice were divided into six groups randomly: sham group, model group, low-, moderate- and high-dose Yizhicongming decoction group, and donepezil group. Aβ_25-35 was injected into the hippocampus of the mice. The mice were orally administered with either Yizhicongming decoction (mainly composed of ginseng, Poria cocos , Polygonum miltiflorum Thunb, and Cistanche deserticola Ma), donepezil or vehicle by gavage once a day continuously for 15 days from the second day after the Aβ_25-35 injection. The expression of phosphorylated Tau protein was measured with Western blot. The morphological changes of hippocampal neurons of the mice were observed with hematoxillin-eosin (HE) staining.

  Results  Compared with those of the sham group, the levels of phosphorylated Tau protein at sites of Ser-396 (1.800 ± 0.172), Thr-231 (2.321 ± 0.140), Thr-181 (2.761 ± 0.250), and Ser-404 (2.761 ± 0.250) in the hippocampus were significantly increased for the mice of model group (P < 0.05 for all). Compared with those of the model group, the levels of phosphorylated Tau protein at sites of Ser-396 (1.006 ± 0.158), Thr-231 (1.384 ± 0.122), Thr-181 (1.164 ± 0.125), and Ser-404 (0.978 ± 0.122) in the hippocampus were significantly increased for the mice of high-dose Yizhicongming decoction group (P < 0.05 for all). The disordered arrangement, edema, and apoptosis of hippocampal nurons were obviously alleviated in the mice treated with Yizhicongming decoction.

  Conclusion  Yizhicongming decoction can reduce neuronal apoptosis through decreasing the expression of phosphorylated Tau in mice with Alzheimer’s disease induced by β-amyloid (Aβ_25-35).