PCNA and Alzheimer disease: The reverse transcription quantitative polymerase chain reaction (RT-qPCR) analysis of proliferation genes was carried out after 72 h of AD-MSCs treatment, and the results showed that mRNA expression of CCND1 and PCNA gene was significantly higher in all treatments, except expression of PCNA in NAC treated group as compared to control, while both gene mRNA was highest in NAC+VC group (p<0.05) (Figures 3E, 3F).