Establishing a Dual Murine Model to Explore the Interactions Between Diabetes and Periodontitis in Mice

Abstract

This study aimed to develop and validate a dual murine model integrating a high-fat diet (HFD) and a single streptozotocin (STZ) dose to induce diabetes mellitus (DM), alongside periodontitis (Perio) induced by ligature placement and oral inoculation with Porphyromonas gingivalis (P. gingivalis). The goal was to mimic human pathological conditions, creating a physiologically relevant environment to study the interplay between DM and Perio. A total of 128 six-week-old male C57BL/6J mice were randomly divided into four groups: Control, DM, Perio, and DM-P. DM was induced by HFD and STZ injection, and Perio by ligature placement and P. gingivalis infection. Evaluations occurred at baseline and days 7, 14, and 21. Alveolar bone loss was assessed by micro-computed tomography, and inflammation was examined histologically. DM mice showed elevated glucose levels and insulin resistance. Perio and DM-P groups experienced significant bone loss compared with Control and DM groups. The morphometric analysis revealed abundant inflammatory cells and reduced collagen fibers in Perio and DM-P groups, especially at day 7. This dual murine model successfully replicated the key features of DM and Perio, maintaining overall health of the animals, and good tolerability by those subjects to the stress of both interventional procedures.

Keywords: diabetes mellitus; ligature; mouse model; periodontitis; streptozotocin.

Figure 1

(A) Experimental design; ‡ inoculation with live Porphyromonas gingivalis in 2% CMC every 2 days for 3 times. (B) Body weight (g) of the animals throughout the study period, presented as the weekly mean. (C) Postprandial blood glucose (mg/dL) of the animals throughout the study period (46 days), presented as the weekly mean. STZ—streptozotocin.

Figure 2

(A) Images obtained from the three-dimensional reconstruction by micro-CT of the maxillary molars of each experimental group at 21 days. (B) Mean and standard deviation (SD) of the linear bone loss (µm) in the interproximal region between the 1st and 2nd maxillary molars on the right side of all groups, at each experimental time point. (C) Mean and SD of the percentage of bone volume obtained from the region of the 1st to 2nd maxillary molars on the right side of all groups at each experimental time point. # Significant difference compared with the Control group; & significant difference compared with the DM group.

Figure 3

(A) Light micrographs of portions of gingival mucosa showing the lamina of mice. Arrow—inflammatory cell; Fb—fibroblasts; BV—blood vessel; ET—epithelial tissue; Col—collagen fibers. Scale Bars: 35 µm. (B–E) Graphics illustrating the volume density of fibroblasts (B), inflammatory cells (C), and blood vessels (D) and volume density of collagen fibers in the lamina propria of gingival mucosa of mice from DM, DM-P, Perio, and Control groups. # Significant difference compared with the Control group; & significant difference compared with the DM group. Values expressed as mean and standard deviation.