Environmental enrichment reduces anxiety-like behavior and changes the microbial community composition of mice

Environmental enrichment (EE) is a husbandry procedure known to provide enhanced somatosensory, locomotor and cognitive stimulation. It has been shown to exert significant beneficial effects on cognitive function improving rodent behavior, altering neuronal plasticity, and promoting stress resilience. Concurrently, emerging research highlights the intricate bidirectional communication between the gut microbiome and central nervous system, known as the microbiota-gut-brain axis. Therefore, the aim of this work is to investigate, whether the beneficial effects of EE are linked to alterations in the gut microbiome composition. Four-week-old C57BL6/J mice were co-housed for four weeks in order to homogenize their microbiome. Afterwards, the mice were split into EE and standard environment (SE) housing and used for behavioral testing and microbiome community analysis. We found that exposure to enriched environments significantly modulates mouse behavior reducing anxiety-like behaviors in the open field test (OFT). Furthermore, analysis of the gut microbiome via 16S rRNA sequencing reveals distinct alterations in microbial diversity and composition in EE mice compared to standard-housed controls. These findings suggest a potential link between environmental enrichment, behavioral improvements and the gut microbiome. Understanding these interactions may pave the way for novel interventions targeting the gut-brain axis to promote gut and brain health.