Thus,
the rice bran diet reduced Salmonella fecal shedding may be a result of the induction of increased colonization resistance in the intestinal lumen as opposed to the increased horizontal transfer of Salmonella into the tissues [31]. Gut inflammation resulting from Salmonella presence favors this website the colonization and growth of the Salmonella because of changes in gut ecology and environment [25]. Local inflammation in the intestine occurs in conjunction with a massive systemic release of TNF-α, IFN-γ and IL-12 [24, 32, 33]. The rice bran fed mice showed a significant reduction in serum inflammatory SB-715992 cytokines associated with Salmonella infection, namely TNF-α, IFN-γ and IL-12 (Figure 2A-C). The presence of Salmonella antigens in the
lumen is in part responsible for inducing STI571 cost the inflammatory cytokines in control diet fed animals. Therefore, a reduced Salmonella antigen load in the lumen of rice bran fed mice may have diminished this inflammatory response. Determining the mucosal immune cells involved in the development of local and systemic inflammation by Salmonella in these mice will be important for understanding the mechanisms by which rice bran modulates the inflammatory response. Given that Salmonella induces changes in the gut microbiome [25, 34], we next explored differences in the gut microbial communities between control and rice bran fed mice as a plausible mechanism for the reduced colonization of Salmonella (Figure 1). Our exploratory data showed increased Firmicutes in rice bran diet fed animals as compared to control animals before infection (Data not shown). The phylum Firmicutes contains the genus Lactobacillus and rice bran fed animals demonstrated a ~170 fold increase in fecal Lactobacillus spp. content as compared to control Docetaxel cost before infection (Figure 3). Probiotic Lactobacillus spp. protect against Salmonella infection through production of lactic
acid that modulates bacterial virulence gene expression and can help maintain tight junctions of mucosal epithelial cells [35–37]. Changes in the gut microbiota by dietary rice bran warrant a separate study to explore this novel mechanism for prevention and reduced susceptibility to Salmonella infection. Rice bran is a collection of numerous bioactive components [17] that may exhibit multiple mechanisms of action for protection against enteric pathogens. Methanol extracts contain bioactive polyphenols and fatty acids from rice bran [38], and were used for the treatment of MSIE cells in vitro. RBE reduced the cellular entry of Salmonella by 27% in comparison to control (Figure 4A). In addition to reduced Salmonella entry, RBE also decreased intracellular Salmonella replication by 30% (Figure 4B).