Effect of Clostridium butyricum against Microglia‐Mediated Neuroinflammation in Alzheimer's Disease via Regulating Gut Microbiota and Metabolites Butyrate

Recent evidences demonstrate that abnormal gut microbiota (GM) might be involved in the pathogenesis of Alzheimer's disease (AD). However, the role of probiotics in preventing AD by regulating GM-gut-brain axis remains unclear. Here, the anti-neuroinflammatory effect and its mechanism of probiotic Clostridium butyricum (CB) against AD is investigated by regulating GM-gut-brain axis.APPswe/PS1dE9 (APP/PS1) transgenic are treated intragastrically with CB for 4 weeks then cognitively tested. Amyloid-β (Aβ) burden, microglial activation, proinflammatory cytokines production, GM, and metabolites butyrate are analyzed. Moreover, Aβ-induced BV2 microglia are pretreated with butyrate, and the levels of cluster of differentiation 11b (CD11b), cyclooxygenase-2 (COX-2), and NF-κB p65 phosphorylation are determined. The results show that CB treatment prevents cognitive impairment, Aβ deposits, microglia activation, and production of tumor necrosis factor (TNF)-α and interleukin (IL)-1β in the brain of APP/PS1 mice. Meanwhile, abnormal GM and butyrate are reversed after CB treatment. Notably, butyrate treatment reduces the levels of CD11b and COX-2, and suppresses phosphorylation of NF-κB p65 in the Aβ-induced BV2 microglia.These findings indicate that CB treatment could attenuate microglia-mediated neuroinflammation via regulating the GM-gut-brain axis, which is mediated by the metabolite butyrate.