Immunization withMycobacterium vaccaeNCTC 11659 prevents the development of PTSD-like sleep and behavioral phenotypes after sleep disruption and acute stress in mice

Because regular sleep disruption can increase vulnerability to stress-related psychiatric disorders, there is a need to explore novel countermeasures to increase stress resilience after inadequate sleep. In this study, we explored the impact of 5 days of intermittent sleep disruption on vulnerability to acute social defeat stress in mice, and investigated the ability of the environmental, immunomodulatory bacterium Mycobacterium vaccae NCTC 11659 (MV) to promote stress resilience in that context. We found that mice receiving sleep disruption plus acute stress developed sleep and behavioral phenotypes that had some features of human posttraumatic stress disorder (PTSD) including reduced NREM delta power and increased NREM beta power in post-stress sleep EEG, persistent increases in sleep fragmentation and the REM:Sleep ratio, and behavioral changes. Importantly, immunization with heat-killed MV prevented the development of this phenotype. These results support further research into novel, microbial-based countermeasures to improve health and increase resilience to sleep disruption.