By regulating NRF2/HO-1 and MyD88/TRAF6/NF-κB, Bacillus coagulans JA845 pretreatment can prevent cognitive decline, reduce hippocampal neuronal damage, protect neuronal integrity, reduce the deposition of A and excessive phosphorus of tau in the hippocampus of AD model mice, as well as OS and serum inflammatory cytokines. The gene discussed is MYD88; the disease is Alzheimer disease.