Fig. 10

Schematic representation of the immune interaction among sex, the gut microbiome and the brain. In response to cerebral ischemia stimulation, the composition of the intestinal microbiota changes correspondingly according to sex. Bacteroides is dominant in females, secreting more SCFAs and Trp, inducing an increase in the anti-inflammatory factors IL4 and IL10 and reducing the brain aggregation of inflammatory cells such as neutrophils, microglia/macrophages, and T and B lymphocytes, thus inhibiting neuroinflammation. The male intestinal environment is conducive to the survival of Firmicutes, producing a large amount of TMAO, which promotes the production of proinflammatory factors and the infiltration of inflammatory cells in the brain, eventually aggravating central inflammation. TMAO trimethylamine oxide, SCFA short-chain fatty acid, Trp tryptophan