HMOX1 and Alzheimer disease: Consistently with the mRNA results, compared with control group, the protein levels of sirtuin1 (Figures 7(a) and 7(d)), total Nrf2 (Figures 7(c) and 7(d)), and nuclear Nrf2 (Figures 7(e) and 7(f)) in PC12 cells were significantly increased (P < 0.05), while the protein expression of HO-1 (Figures 7(b) and 7(d)) was significantly decreased in the AD model group (P < 0.05).