While inflammatory bowel disease (IBD) might be a risk factor in the development of brain dysfunctions,the underlying mechanisms are largely unknown.Here,mice were treated with 5％ dextran sodium sulfate (DSS) in drinking water and sacrificed on day 7.The serum level of IL-6 increased,accompanied by elevation of the IL-6 and TNF-α levels in cortical tissue.However,the endotoxin concentration in plasma and brain of mice with DSS-induced colitis showed a rising trend,but with no significant difference.We also found significant activation of microglial cells and reduction in occludin and claudin-5 expression in the brain tissue after DSS-induced colitis.These results suggested that DSS-induced colitis increases systemic inflammation which then results in cortical inflammation via up-regulation of serum cytokines.Here,we provide new information on the impact of colitis on the outcomes of cortical inflammation.