Effects of Green Tea and Java Pepper Mixture on Gut Microbiome and Colonic MicroRNA-221/222 in Mice with Dextran Sulfate Sodium-Induced Colitis

In this study, we aimed to investigate the regulatory effects of a green tea and java pepper mixture (GTP) on the gut microbiome and microRNA (miR)-221/222 expression in mice with dextran sulfate sodium (DSS)-induced colitis. Male C57BL/6J mice were divided into four groups: DSS-, DSS+, GTP50, and GTP100. In the GTP50 and GTP100 groups, GTP was orally administered to mice at doses of 50 and 100 mg/kg body weight, respectively, every day for 2 weeks, and colitis was induced in the DSS+, GTP50, and GTP100 groups by adding 3% DSS to their drinking water for 1 week. GTP was found to mitigate the severity of inflammation and the damage to goblet cells caused by DSS-induced colitis. The results showed that compared with the DSS- group, the relative abundance of <i>Bacteroidetes</i> was increased and that of <i>Proteobacteria</i> and <i>Candidatus Melainabacteria</i> was decreased in the GTP100 group. The ratio of <i>Firmicutes</i> to <i>Bacteroidetes</i> was also reduced in the GTP100 group. However, GTP administration did not modulate the microbial diversity. GTP administration upregulated the mRNA and protein levels of occludin and zonula occludens 1. In addition, GTP effectively downregulated the expression of miR-221 and miR-222. Overall, GTP altered the gut microbiota composition and downregulated colonic miR-221/222 expression in mice with DSS-induced colitis.