Iron supplementation is necessary for the treatment of
anemia, one of the most frequent complications in
inflammatory bowel disease (IBD). However, oral
iron supplementation leads to an exacerbation of intestinal
inflammation. Gut barrier plays a key role in the pathogenesis of IBD. The aim of this study was to characterize the interrelationship between systemic
iron, intestinal barrier and the development of intestinal
inflammation in a
dextran sulfate sodium (DSS) induced experimental
colitis mice model. We found that DSS-treated mice developed severe
inflammation of colon, but became much healthy when
intraperitoneal injection with
iron.
Iron supplementation alleviated colonic and systemic
inflammation by lower histological scores, restorative morphology of colonic villi, and reduced expression of pro-inflammatory
cytokines. Moreover, intraperitoneal supplementation of
iron enhanced intestinal barrier function by upregulating the colonic expressions of
tight junction proteins, restoring intestinal immune homeostasis by regulating immune cell infiltration and T lymphocyte subsets, and increasing mucous secretion of goblet cells in the colon. High-throughput sequencing of fecal 16 S rRNA showed that
iron injection significantly increased the relative abundance of Bacteroidetes, which was suppressed in the gut microbiota of DSS-induced
colitis mice. These results provided evidences supporting the protective effects of systemic
iron repletion by
intraperitoneal injection of
iron on intestinal barrier functions. The finding highlights a novel approach for the treatment of IBD with
iron injection
therapy.