Repeated mild traumatic brain injury affects microbial diversity in rat jejunum

ABSTRACT

Traumatic brain injuries (TBI) manifest into post-traumatic stress disorders such as anxiety comorbid with gut ailments. Theperturbations in gut microbial communities are often linked to intestinal and neuropsychological disorders. We havepreviously reported anxiety and abnormalities in gut function in mild TBI (MTBI)-exposed rats. The current studydemonstrates the changes in gut microbiome of MTBI-exposed animals and discusses its implications in intestinal healthand behaviours. The rats were subjected to repeated MTBI (rMTBI) and microbial composition in jejunum was examinedafter 6 h, 48 h and 30 days of rMTBI. Significant reduction in bacterial diversity was observed in the rMTBI-exposedanimals at all the time points. Principal coordinate analysis based on weighted UniFrac distances indicated substantialdifferences in gut microbial diversity and abundances in rMTBI-exposed animals as compared to that in healthy controls.The abundance of Proteobacteria increased dramatically with reciprocal decrease in Firmicutes after rMTBI. At the genuslevel, Helicobacter, Lactobacillus, Campylobacter, and Streptococcus were found to be differentially abundant in thejejunum of rMTBI-exposed rats as compared to sham controls indicating profound dysbiosis from the healthy state.Furthermore, substantial depletion in butyrate-producing bacterial communities was observed in rMTBI-exposed animals.These results suggest that the traumatic stress alters the gut microbiome with possible implications in gut health andneuropsychopathology.