BDNF and inflammatory bowel disease: In addition, the previous study also pointed out that inflammatory bowel disease (IBD) could lead to neuroinflammation in a bottom-up manner, and this effect depended on the brain region: the upregulation of cyclooxygenase-2 (COX-2) mRNA, glial fibrillary acidic protein (GFAP) mRNA, and GFAP expression during exposure to dextran sulfate sodium salt (DSS) in the hippocampus; upregulation of COX-2 mRNA only 3 days after DSS treatment in the hypothalamus; downregulation of brain-derived neurotrophic factor (BDNF) and COX-2 mRNAs in the amygdala (Do and Woo, 2018).