Immune-Inflammatory Imbalance in Mice Under High Humidity and Three Different Ambient Temperatures: Insights From Gut...

Gut microbiota and metabolites have been increasingly implicated in the pathogenesis of immune inflammation, which may be affected by environmental factors. This study aimed to explore the influence of co-exposure to high humidity and temperatures (low, normal or high) on biomarkers of immune inflammation and potential mechanisms. We established C57BL/6J mice models (with equal numbers of males and females) of high humidity and low temperature (HH-LT), normal temperature (HH-NT) or high temperature (HH-HT) co-exposure environments to observe the impact of high humidity and different temperature co-exposure environments for 28 and 56 consecutive days. Following exposure, results showed that all six combined exposure conditions significantly increased pro-inflammatory cytokines (TNF-α, IL-1β, IL-12p70), decreased anti-inflammatory cytokines (IL-4, IL-10) and elevated the Teff/Treg ratio in the spleen. Gut microbiota analysis revealed reduced Akkermansia and increased Desulfovibrio and Enterorhabdus. Serum metabolomics identified widespread disturbances enriched in pathways including protein digestion and absorption, lysine degradation, phenylalanine metabolism and unsaturated fatty acid biosynthesis. Pearson correlation analysis confirmed significant associations among microbial shifts, immune-inflammatory dysregulation and metabolic perturbations-suggesting that high humidity combined with different temperatures correlated with immune imbalance, likely mediated by gut dysbiosis and serum metabolic disruption.