Effects of curcumin on abnormal cell cycle and apoptosis of serum-deprived PC12 cells induced by β-amyloid peptide(25-35)

Objective: To assess effects of curcumin(Cur)on abnormal cell cycle and apoptosis of β-amyloid peptide 25-35(Aβ25-35)-induced serum-deprived PC12 cells.Methods: PC12 cells at synchronized G0 stage were cultured in serum-deprived media for 24 hours.The PC12 cells were then incubated with Cur at a series of concentrations(0,1.25,2.5,5,10,20 μmol·L-1) for one hour,respectively,followed by the incubation with Aβ25-35 for 24 hours.Cell survival rate was evaluated by MTT assay.The status of cell cycle distribution and apoptosis was analyzed by flow cytometry.The morphodifferentiation of apoptotic nuclei was analyzed by Hoechst-PI fluorescence staining.Protein and mRNA expression that were modulated by p21 gene was monitored by RT-PCR and Western-blot,respectively.Results:The survival rate of the PC12 cells increased in a dose-dependent manner and the percent of S phase cells and apoptotic rate was decreased remarkably(P0.01)after the incubation with Aβ25-35.The hypodiploid peak ahead of G0/G1 phase disappeared,and karyopyknosis and nucleus cataclasm reduced.The expression of p21 onto mRNA and protein was shown an increase.Conclusion: Cur impacts the cellular cycle and apoptosis of Aβ25-35-induced serum deprived PC12 cells by up-regulation of the p21 gene expression.