BCL2 and Alzheimer disease: The expression of PKAc and p-CREB protein decreased, suggesting that the neurotoxicity of the cortex and hippocampus of AD mice may be related to the inhibition of the cAMP/PKA/CREB signalling pathway, further downregulate the anti-apoptotic gene Bcl-2 and upregulate the pro-apoptotic gene Bax, and then promote apoptosis.