Gut microbiota and metabolic profile changes unveil the deterioration of alveolar bone inflammatory resorption with aging induced by D-galactose

Abstract The global aging population has led to a rise in age-related health issues, such as malnutrition, metabolic disorders, and even immune decline. Among these concerns, periodontitis holds particular significance for the well-being of the elderly. This study aimed to investigate the impact of aging on inflammatory resorption of alveolar bone in mice with periodontitis, with a specific focus on alterations in the intestinal microenvironment. To achieve this, we established a D-galactose (D-gal)-induced aging mouse model with periodontitis and employed histopathological staining, oxidative stress, and inflammatory factors analyses to assess the severity of periodontitis and the health status. Additionally, the 16S rRNA sequencing and untargeted metabolomics analysis were employed to investigate alterations in the intestinal microbiota and metabolites. Our results showed that D-gal-induced aging mice with periodontitis experienced more pronounced alveolar bone inflammatory resorption and disruptions in the gut barrier, accompanied by an overall decline in physical condition. The microbial composition and structure of aged mice also underwent significant modifications, with a decreased Firmicutes/Bacteroidetes (F/B) ratio. Furthermore, metabolomics analysis demonstrated that D-gal-induced aging primarily influenced lipids and lipid-like molecules metabolism, and enrichment observed in the rheumatoid arthritis and histidine metabolism pathways. These findings provide further evidence that the aging process exacerbates age-related alveolar bone loss (ABL) through disturbances in intestinal homeostasis.