Probiotic treatment improves post-traumatic stress disorder outcomes in mice.

Post-traumatic stress disorder (PTSD) is a mental disorder resulting from traumatic events which are characterized primarily by anxiety and depressive disorder. In this study, we determine the role of gut bacteria in PTSD. PTSD-like symptoms were produced by single prolonged stress (SPS). SPS animals showed increased levels of anxiety as measured by the elevated plus maze test, while depressive behaviour was confirmed using sucrose preference, force swim, and tail suspension tests. Gut dysbiosis was confirmed in PTSD animals by next-generation sequencing of 16 s RNA of faecal samples, while these animals also showed increased intestinal permeability and altered intestinal ultrastructure. Probiotic treatment increases beneficial microbiota, improves intestinal health and reduces PTSD-associated anxiety and depression. We also found a decrease in cortical BDNF levels in PTSD animals, which was reversed after probiotic administration. Here, we establish the link between gut dysbiosis and PTSD and show that probiotic treatment may improve the outcome of PTSD like symptoms in mice.