Fig. 5

Neuroinflammation in experimental NEC is associated with a gut-brain axis. a Representative images of the intestinal epithelium of pups induced NEC and breastfed control pups. NEC induction caused severe damage to the ileum of mice; scale bar = 100 μm. b Compared to breastfed control (n = 38), pups that underwent NEC induction protocol (n = 45) had a higher intestinal severity score. c ELISA quantification of IL-6 (pg/mg) in the brain of NEC and breastfed control pups. Compared to breastfed control, the protein level of IL-6 increased in the brain of NEC pups. d ELISA quantification of IL-6 (pg/mg) in the ileum of the same NEC and control pups. Compared to control, the protein level of IL-6 increased in the ileum of NEC pups. e ELISA quantification of TNFα (pg/mg) in the brain of NEC and control pups. Compared to breastfed control, the protein level of TNFα increased in the brain of NEC pups. f ELISA quantification of TNFα (pg/mg) in the ileum of the same NEC and breastfed control pups. Compared to breastfed control, the protein level of TNFα increased in the ileum of NEC pups. g Pearson correlation of IL-6 levels of brain and ileum from the same pups, both breastfed control and NEC. There was a significant positive correlation between increasing IL-6 levels in the brain and in the ileum. h Pearson correlation of TNFα levels of the brain and ileum from the same pups, both breastfed control and NEC. There was a significant positive correlation between increasing TNFα levels in the brain and in the ileum. i Pearson correlation of intestinal severity score and the number of activated microglia in the hippocampus. There was a significant positive correlation between increasing NEC severity and density of activated microglia. j Pearson correlation of intestinal severity score and the number of astrocytes in the hippocampus. There was a significant positive correlation between increasing NEC severity and density of astrocytes in the hippocampus. Scale bar = 100 μm