<i>Bacillus amyloliquefaciens</i> SCGB1 Alleviates Dextran Sulfate Sodium-Induced Colitis in Mice Through Immune Regulation

Abstract

Probiotics, as living microorganisms, exert health benefits to the host by alleviating excess inflammation through modulating the immune system and establishing intestinal homeostasis. In this study, we evaluated the probiotic characteristics and inflammation alleviatory effects of <i>Bacillus amyloliquefaciens</i> isolated from traditional Korean fermented foods. The strains withstood the acidic environment of the digestive process, extended the lifespan of <i>Caenorhabditis elegans</i>, and enhanced <i>pmk-1</i> expression. However, only <i>B</i>. <i>amyloliquefaciens</i> SCGB1 could attach to <i>C. elegans</i> in the intestines, which enhanced their survival upon exposure to <i>Escherichia coli</i> O157:H7. We also investigated the anti-inflammatory effect of SCGB1 using the RAW264.7 macrophage stimulated with lipopolysaccharide. The strain treatment enhanced anti-inflammatory cytokine interleukin (IL)-10 secretion and downregulated proinflammatory cytokine IL-6 expression <i>in vitro</i>. Next, we used a dextran sulfate sodium (DSS)-induced colitis mouse model to investigate whether SCGB1 can ameliorate gut inflammation <i>in vivo</i>. Compared to those in the DSS-induced mice, histological damage and IL-6 cytokine levels were significantly reduced in SCGB1-fed mice. These results suggest that <i>B. amyloliquefaciens</i> SCGB1 as potential probiotics may have health-promoting effects by reduction of inflammatory responses.