Abstract
Dietary administration of lactobacilli and certain fibres significantly reduced the severity of methotrexate-induced enterocolitis in rats by improving intestinal mucosal structure, reversing microbiota disruption, possibly also influencing intestinal mucosal immunity. The purpose of this study was to evaluate the effects of two Lactobacillus strains and fibres, which have been proven to be effective in enterocolitis of rats, on gut immune response. All rats received continuous intragastric infusion of an elemental diet with or without supplementation of pectin, oatbase, and Lactobacillus reuteri R2LC or Lactobacillus plantarum DSM 9843 from the beginning of the study via a gastrostomy. The control group rats had normal chow throughout the study. On day three, animals received intraperitoneal injections of either methotrexate, 20 mg/kg, or normal saline, and the sampling was done on day six. Administration of methotrexate significantly diminished intestinal secretory IgA level and gut lamina propria CD4/CD8 lymphocyte counts. The addition of L. reuteri R2LC, and L. plantarum DSM 9843, but not of pectin and oatbase, significantly increased the ileal and colonic secretory IgA level, both in soluble and insoluble fractions, and elevated CD4 and CD8 numbers compared with control enterocolitis rats. The enhancement of gut immune function by lactobacilli administration may be one of the important processes through which certain strains of lactobacilli facilitated the recovery from enterocolitis.