Analysis of relation between chronic ethanol consumption and fecal microbiota structure in mice with chronic ethanol administration

Chronic ethanol consumption has been shown to be one of the major risk factors for colorectal cancer (CRC). It has been proposed that ethanol and its metabolites promote inflammation and oxidative stress of the colon and rectum via multiple pathways, which leads to CRC. In the colorectal epithelial cells, ethanol oxidation, coupled with the mitochondrial electron transport system, coincidentally gives rise to the formation of reactive oxygen species (ROS). We analyzed and compared the gut microbiota structures of alcoholic and non-alcoholic people to identify the ecophysiological consequences of alcoholism on human gut microbiota. The results showed that the gut microbiotas of alcoholics were in a dysbiosis state, in which obligate anaerobes decreased and facultative anaerobes were enriched. Because obligate anaerobes are generally more susceptible to ROS than facultative anaerobes, these observations were consistent with the proposed sustained formation of ROS and ROS-induced oxidative stress in the colonic environment during chronic ethanol consumption. In this study, the effects of chronic ethanol administration on the fecal microbiota structures were comprehensively investigated in mice.