To investigate whether the improved cognitive function is related to ROS, apoptosis and/or the phosphorylation of tau protein, we examined their levels in old CpGfapcKO mice, and found a significant decrease in apoptosis accompanied with decreased oxidative stress, increased Bcl-2/Bax ratio, decreased tau phosphorylation and diminished activity of the Erk/p38 MAPK pathway, all of which are linked to a delay in the pathogenesis of AD. This evidence concerns the gene BCL2 and Alzheimer disease.