Objective To investigate the effect of the peptide APP17 on regulating the expression of Bcl\|2,Bax,cAMP response element binding Protein(CREB),Ser\|Thr kinase B/protein kinase B(Akt/PKB),apoptosis inducing factor(AIF) in neurons of the hippocampus from the D\|gal mouse. Methods D\|gal mouse models were established by injection of D\|gal.In experimental group,these models were injected with APP17 petide subcutaneously and their brain sections were taken after 3 months of survival.The immunohistochemical staining of these sections was then performed with Bcl\|2,Bax,CREB,Akt,AIF antibody. Results Bax,AIF positive neurons were widely distributed in the hippocampus of the D\|gal mice,and the cytoplasm was darkly stained.In contrast,positive cells in the hippocampus were poorly stained in those normal mice and the APP17 peptide\|treated D\|gal mice.But Bcl\|2,CREB,AKt positive neurons were widely distributed in the hippocampus of those normal mice and the APP17 peptide\|treated D\|gal mice,and the cytoplasm was darkly stained.In contrast,positive cells in the hippocampaus were poorly stained in the D\|gal mice.Conclusion\ The expression of Bax and AIF could be increased in the hippocampus of D\|gal mice.But the expression of Bcl\|2,CREB,AKt decreased in the hippocampus of D\|gal mice.The APP17 can regulate the distribution of Bcl\|2,Bax,CREB,Akt,AIF in the brain of D\|gal mice and return them to normal situation.\;[