Effect of oral dextran sulfate on the mouse intestinal tract

Oral dextran sulfate is associated with adverse intestinal effects, including severe diarrhea, in some AIDS patients. We therefore investigated the intestinal flora and the intestinal histology of mice given drinking water supplemented with 8 mg/ml of dextran sulfate. There were no noticeable alterations in the major groups of intestinal bacteria in mice given oral dextran sulfate for 7 days. Likewise, there was no abnormal pathology in the ilea or colons of mice treated for 7 days with oral dextran sulfate. However, after 21 and 38 days, there was a noticeable overgrowth of facultative gram-negative bacilli in the colonic and cecal flora of dextran sulfate-treated mice. This overgrowth appeared to be due to bacterial species in the family Enterobacteriaceae, primarily Escherichia coli. Bacterial overgrowth was accompanied by mild histological alterations in the intestinal mucosa, i.e., blunting of ileal villi and colonic crypts, with mild epithelial cell dysplasia. Thus, oral dextran sulfate was associated with quantitative changes in the mouse intestinal flora, as well as histological changes in the intestinal mucosa.