Reduction in mucosal barrier markers with soy protein diet but not probiotic in DSS‐treated mice

Abstract

Dietary interventions for reducing the symptoms of inflammatory bowel disease (IBD) are urgently needed. Dextran sodium sulfate (DSS) affects the mucosal barrier of the colon to allow interaction of commensal bacteria with the mucosa and is a useful model of IBD. The mucins (MUC) and trefoil factors (TFF), secreted by mucosal cells, are the first line of defense for the colonic mucosa. Our objective was to determine if diet and/or the probiotic bacterium Lactobacillus rhamnosus GG (LGG) would mediate the damage of DSS by altering expression of the MUC and TFF genes. Mice were fed diets containing casein, soy or whey protein −/+ LGG for 12 days. Seven days after starting LGG diets, the mice were given 2% DSS in the drinking water for 4 days. One day after the DSS treatment the colon and cecum mucosa were obtained. The quantity of LGG present in the cecum was highest in mice fed whey and lowest in mice fed soy. MUC1 and TFF3 were induced by DSS in colon of casein fed mice, but dramatically suppressed by soy protein. A similar response was observed for TNF-α in both colon and cecum. The soy diet also tended to prevent DSS induced changes in MUC2, MUC3 and MUC4. Overall, LGG had minor influence on MUC or TFF expression in either colon or cecum. Hence diet but not probiotic affected the colonic mucosal barrier in DSS-treated mice. Funded by a USDA special grant.