Effects of chronic allergic lung inflammation on gut microbiota and depression-like behavior in mice.

Aim: Emerging epidemiological studies have reported a link between allergic diseases, including asthma, and depression. Evidently, the gut microbiota is involved in the pathogenesis of asthma and depression. Therefore, we investigated whether allergic lung inflammation in mice causes gut microbial dysbiosis, via the gut-brain axis, which is potentially associated with depression. Methods: Wild-type C57BL/6J female mice were sensitized with intranasal house dust mite (HDM) antigen or phosphate-buffered saline (PBS) for 6 weeks to induce chronic allergic lung inflammation. Sucrose preference tests were performed for assessing depression. Fecal samples were collected, and 16S ribosomal RNA gene sequencing was performed to detect differences in gut microbiota composition between the HDM and PBS groups. The distance calculation, clustering of operational taxonomic units, rarefaction analysis, and estimator calculation (α- and β-diversity) were performed. Results: There was a significant difference in β-diversity (Bray-Curtis dissimilarity, Conclusions: Six weeks of intranasal HDM administration to mimic the chronic status of lung inflammation in asthma changed the gut microbiome in mice and was associated with depression-like behavioral changes.