Expression of the receptor of advanced glycation end products in gingival tissue endothelial cells from type 2 diabetic rats with chronic periodontitis

To evaluate the expression of the receptor for advanced glycation end products (RAGE) in gingival tissue endothelial cells from type 2 diabetic rats with chronic periodontitis and to explore the role of RAGE in the pathogenesis of diabetes in cases with chronic periodontitis.

Sixty 7-week-old female Wistar diabetic obese rats were randomly divided into two groups. Periodontitis was induced in 30 rats by silk ligation, and the other 30 rats were used as the control group in which the periodontal tissues were not treated. One week after periodontal ligation and inoculation, the periodontitis and control group rats were randomly divided into two subgroups; the first subgroup was fed a high-fat diet, and the second group was fed a low-fat diet. Thus, 15 rats per group were included in the high-fat diet periodontitis (HF/P), low-fat diet periodontitis (LF/P), high-fat diet periodontal health (HF/C), and low-fat diet periodontal health (LF/C) groups. Glucose tolerance tests were performed weekly to measure the fasting insulin and blood glucose levels and the insulin resistance index to verify successful construction of the rat diabetes model. After successful modeling of chronic periodontitis, the rats were sacrificed at the 13th week after measurement of the serum necrosis factor-α (TNF-α), interleukin-6 (IL-6) and leptin levels. The tooth periodontal tissues were prepared and sectioned to observe histological changes. Immunofluorescence double staining was used to detect the density of RAGE-positive endothelial cells in the gingival tissues of the four groups.

The serum fasting blood glucose and insulin levels and insulin resistance index were significantly higher in the HF/P and HF/C groups than in the LF/P and LF/C groups (P < 0.01). The serum TNF-α and IL-6 levels were significantly higher in the HF/P and LF/P groups than in the HF/C and LF/C groups (P < 0.01). The serum leptin levels were significantly higher in the HF/P group than in the other three groups. The density of RAGE-positive endothelial cells was significantly higher in the HF/P and HF/C groups than in the LF/P (P＝0.001) and LF/C groups (P＝0.040). The density of RAGE-positive endothelial cells in the HF/P group was higher than that in the HF/C group (P＝0.027).

Endothelial cells in type 2 diabetic rats with periodontitis have increased gingival tissue RAGE and serum leptin levels.