If You Give a Mouse a Habitat: How the Environment Alters the Oral Microbiome and Shapes Periodontal Bone Loss

Abstract

Laboratory mice are commonly used to model oral diseases like periodontal disease. However, their lack of exposure to environmental pathogens may limit the translatability of these mouse models to real-world organisms. Rewilding solves this problem by exposing laboratory mice to outdoor conditions, but the effects on the oral microbiome and periodontal pathology remain poorly understood. In this study, I explored how rewilding alters the oral microbiome and shapes periodontal bone loss in C57BL/6J mice. To do so, I use culturing procedures, 16S rRNA sequencing, ITS sequencing, and distance measurements from the cementoenamel junction (CEJ) to alveolar bone crest (ABC) to compare groups of lab-housed and rewilded mice. I found that rewilded mice had greater absolute abundances of culturable fungi, aerobic bacteria, and anaerobic bacteria. Rewilded mice also had significantly different bacterial community compositions compared to their lab-housed counterparts. However, I found no significant differences for the alpha diversity of either bacteria or fungi. While rewilded mice did have slightly greater periodontal bone loss, the observed differences were not significant. Attempts to correlate specific bacterial taxa with increased bone loss distances identified emerging trends, but I found no significant associations after multiple testing corrections. These findings suggest that while rewilding alters the oral microbiome composition and increases microbial burden, the given 5 week timeframe may not have been sufficient to induce significant periodontal bone loss. As a result, future research should utilize longer rewilding studies to create more representative animal models and more comprehensively understand how the environment can shape the oral microbiome and disease progression.