Effects of Puerarin on protein expression of hyperphosphorylated tau and ChAT in hippocampus of Alzheimer's disease rats

Objective To investigate the effects of Puerarin on the expression of hyperphosphorylated-tau (P_ ser404-tau) and choline acetyltransferase (ChAT) in hippocampus of Alzheimer's disease(AD) rats.Methods The rats were divided into sham-operation group, AD group and Puerarin treated group at randomly. The AD rat models were established by injecting amyloid-beta peptide(Aβ_ 25-35) into right amygdala. The sham-operation rats were injected with trifluoroacetic acid in the same location. The spatial memory function was observed by Y-maze. The protein expression of P_ ser404-tau and ChAT in hippocampus were detected by immunohistochemistry.Results (1)Compared with sham-operation group,the results of maze test were down in AD group and the number of P_ ser404-tau positive cells was significantly higher,while the number of ChAT positive cells was significantly lower (all P0.01).(2)The spatial memory deficit of AD rats was improved remarkably after Puerarin treatment( P0.05). There were down-regulation of P_ ser404-tau expression and up-regulation of ChAT activities expression in Puerarin treated group compared to AD group(all P0.01).Conclusions Puerarin can attenuate the neurotoxicity of Aβ and improve the learning and memory function in AD rats. The treatment mechanism of Puerarin may be associated with restraining hyperphosphorylation of tau protein relieving cholinergic nerve injury and improving ChAT function and synthesis of acetylcholine in central nervous system.