Gut Dysbiosis Minimal Enteritis Induced By High Temperature and Humidity. HTH-microbiota

High temperature and humidity (HTH) can cause diarrhea due to food and drinking water contamination. However, its direct effects on the gut microbiota and gastrointestinal inflammation are unknown. To investigate the effects of HTH and probiotics on the microbiome, 21 male mice were randomly assigned into normal control (NC), HTH, and probiotic-treated (PR) groups. HTH and PR groups were regularly housed at 35 ± 0.15 C with humidity of 90–95% for eight consecutive weeks. A broad-spectrum probiotic was administrated to PR-group mice from day 50 to 56. Clinical signs were observed and the gut microbiota was analyzed by 16S rRNA-based metagenomics. Microbial community structures were defined, and univariate, multivariate, and correlation analyses were performed on bacterial profiles. Functional metagenome analysis was performed based on 16S rRNA. Intestinal pathology and the expression of defensins and pro-inflammatory cytokines were also assessed. Mice in HTH and PR groups gradually developed loose feces, which peaked at 2 weeks and then gradually subsided. The HTH group developed a distinct microbiota profile associated with augmented metabolism and human disease pathways with suppression of the environmental information processing pathway. Pathological assays indicated minimal enteritis, increased bacterial translocation, and elevated plasma LPS and pro-inflammatory cytokine levels. These abnormalities were partially rescued by probiotics. Thus, ambient HTH directly contributes to gut dysbiosis and minimal enteritis. Broad spectrum probiotics improved disease signs, partially normalized the microbiota, and ameliorated gut inflammation. This study sheds new light on the pathogenesis of climate-associated diseases and offers a possible therapeutic approach.