Enteric Protective Effects of the Combination Bifidobacterium Longum and Lactoferrin in a Rat Model of Diclofenac-Induced Intestinal Injury

Introduction. Use of nonsteroidal anti-inflammatory drugs (NSAIDs) is associated with the occurrence of adverse reactions both in the upper and lower digestive tract. The pathophysiology of NSAID-induced bowel damage is still unclear, but an involvement of the enteric bacterial flora and mucosal inflammation has been suggested. Increasing evidence suggests also that appropriate manipulations of the enteric microbiome through probiotics and/or prebiotics could represent a useful strategy for the management of bowel disorders associated with inflammatory conditions. Based on this background, this study examined the ability of the combination Bifidobacterium longum (BIF) and lactoferrin (LAC) of preventing mucosal damage in a rat model of diclofenac (DIC)-induced small bowel injury. Methods. Enteropathy was induced in rats by intragastric DIC administration (4 mg/kg BID) for 14 days. Control animals received drug vehicle (1% methylcellulose). Subgroups of rats received BIF (2.5X106 CFU/rat/BID), LAC (100 mg/kg BID) or their combination 1 hour before DIC. Doses of BIF and LAC were selected on the basis of preliminary dose-finding experiments. At the end of treatments, blood samples were collected to evaluate hemoglobin (Hb) concentration (indirect index of digestive bleeding). Feces were collected to quantify the calprotectin content (index of intestinal inflammation). Small intestine was excised and the ileum processed for: 1) assay of tissue myeloperoxidase (MPO) levels, as a marker of inflammatory neutrophil infiltration; 2) assay of tissue malondialdehyde (MDA) concentration, as an index of lipid peroxidation. Results. DIC-treated displayed a 40% mortality rate, while in groups treated with DIC+LAC the mortality rate was lower (13.3%). No deaths were observed in controls or rats treated with DIC+BIF or DIC+BIF+LAC. DIC administration significantly decreased blood Hb levels (-38.3%). In DIC-treated rats, LAC, BIF or their combination elicited significant increments of blood Hb, as compared with DIC alone. MPO and MDA levels in the ileum from DICtreated rats were significantly increased, as compared with controls (+223.3% and +102.8%, respectively). The administration of LAC, BIF or BIF+LAC to DIC-treated animals reduced significantly both MPO and MDA levels, as compared with DIC alone. Fecal calprotectin levels in DIC-treated rats were significantly increased, as compared with controls (+127.4%), while in rats co-treated with LAC, BIF or BIF+LAC, fecal calprotectin levels were significantly decreased as compared to DICLO alone. Conclusion. LAC or BIF treatment significantly prevents DIC-induced intestinal damage, this entero-protective effect being associated with a decrease in tissue inflammation, oxidative stress and digestive bleeding. The combination of BIF+LAC does not appear to allow further improvements of the NSAID-induced intestinal injury.