160. Prebiotic-associated Changes in Gut Microbiota Affect the Stress-Induced Inflammatory Response

Stressor exposure increases inflammatory (CINC-1. IL1β, IL6, IL10) and stress (Hsp72) proteins in the absence of a foreign antigen. Recent evidence suggests that compromise of intestinal barrier integrity and increased translocation of bacteria from the intestinal lumen may contribute to these effects. Bifidobacteria and Lactobacilli are commensal bacteria found in the gut and are associated with improved intestinal epithelial integrity and attenuated bacterial translocation following stress. Prebiotics, a form of non-digestible dietary fiber, can promote the growth of select beneficial bacteria in the gut. We therefore hypothesized that two prebiotics, Galactooligosaccharides (GOS) and Polydextrose (PDX), would increase Bifidobacterium spp. and Lactobacillus spp. and reduce the impact of stress on inflammatory and stress proteins. Juvenile Fisher rats (PND 24, 8/grp) were fed a diet containing GOS/PDX for 4 weeks and exposed to inescapable tail shock stress (100 1.5 mA tail shocks) or remained in their home cages. Mesenteric lymph nodes, spleen, adipose and plasma were immediately collected after IS. Fecal samples were collected on the fourth week prior to stress, and plated on media selective for Bifidobacterium spp. and Lactobacillus spp. Diets containing GOS/PDX increased Bifidobacterium spp. and Lactobacillus spp., reduced stress-induced Hsp72 responses, and had little effect on the inflammatory protein response. These data suggest that GOS/PDX alters aspects of the stress response perhaps by modulating the gut microbiota. Supported by Mead Johnson Pediatric Nutrition Institute.