Continuous glucose monitoring reveals periodontitis-induced glucose variability, insulin resistance, and gut microbiota dysbiosis in mice

Diabetes mellitus (DM) management has advanced from self-monitoring blood glucose (SMBG) to continuous glucose monitoring (CGM), which better prevents complications. However, the influence of periodontitis—a common DM complication—on glucose variability is unclear. This study examined glucose variability in mice with periodontitis using CGM. Periodontitis was induced in 9-week-old male C57BL/6J mice via silk ligatures around the upper second molars. Glucose levels were monitored over 14 days with CGM, validated by SMBG. On day 14, samples were collected to assess alveolar bone resorption and serum levels of tumor necrosis factor-α (TNF-α), insulin, and amyloid A. Glucose tolerance test (GTT) and insulin tolerance test (ITT) were conducted to evaluate insulin resistance. Gut microbiota diversity was also analyzed. By day 10, mice with periodontitis exhibited higher mean glucose levels and time above range than controls. On day 14, serum insulin and amyloid A levels significantly increased, while TNF-α remained unchanged. GTT and ITT indicated insulin resistance. Microbiota analysis showed reduced alpha- and altered beta-diversity, with decreased Coprococcus spp. and increased Prevotella spp., linking dysbiosis to insulin resistance. Periodontitis disrupts glucose regulation by promoting insulin resistance and gut microbiota imbalance, leading to significant glucose variability.