The expressions of inflammatory factors and tissue inhibitor of matrix metalloproteinase-2 in human chronic periodontitis with type 2 diabetes mellitus

Abstract

Purpose: The purpose of this study was to observe and quantify the expression of interleukin-4 (IL-4), interferon-gamma (IFN-gamma), and tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) in the gingival tissue of patients with type 2 diabetes mellitus (DM) and healthy adults with chronic periodontitis.

Methods: Twelve patients with type 2 DM and chronic periodontitis (Group 3), twelve patients with chronic periodontitis (Group 2), and twelve healthy individuals (Group 1) were included in the study. Clinical criteria of gingival (sulcus bleeding index value, probing depths) and radiographic evidences of bone resorption were divided into three groups. The concentrations of cytokines were determined by a western blot analysis and compared using one-way ANOVA followed by Tukey's test.

Results: The expression levels of IFN-gamma and TIMP-2 showed an increasing tendency in Groups 2 and 3 when compared to Group 1. On the other hand, the expression of IL-4 was highest in Group 1.

Conclusions: The findings suggest that IFN-gamma and TIMP-2 may be involved in the periodontal inflammation associated with type 2 DM. IL-4 may be involved in the retrogression of the periodontal inflammation associated with type 2 DM.

Keywords: Chronic periodontitis; Tissue inhibitor of metalloproteinases; Type 2 diabetes mellitus.

Figure 1

(A) Interleukin (IL)-4 western blot analysis showing 4 representative samples in each group. IL-4 levels were quantified on the basis of β-actin levels. IL-4 corresponding to molecular weight 18 kDa was shown to be expressed in all samples including healthy gingiva, and the expression levels of IL-4 were decreased in order of Groups 1-3. (B) Graphics showing the average amounts (ratio of IL-4/β-actin) and standard deviation of IL-4 level in Groups 1-3. In the healthy gingival tissues (Group 1), the levels of IL-4 were significantly decreased as compared to Groups 1 and 2 (P < 0.05). ^*Significant difference between Groups 1 and 3 (P < 0.05). ^†Significant difference between Groups 1 and 2 (P < 0.05). Group 1: healthy gingiva from systemically healthy individuals, Group 2: inflamed gingiva from patients with chronic periodontitis, Group 3: inflamed gingiva from patients with chronic periodontitis and type 2 diabetes mellitus.

Figure 2

(A) Interferon (IFN)-γ western blot analysis showing 4 representative samples in each group. IFN-γ levels were quantified on the basis of β-actin levels. IFN-γ corresponding to molecular weight 20-25 kDa was shown to be expressed in all samples including healthy gingiva. The expression levels of IFN-γ increased in order of Groups 1-3. (B) Graphics showing the average amounts (ratio of IFN-γ/β-actin) and standard deviation of IFN-γ level in Groups 1-3. In the inflamed gingiva (with or without diabetes, Groups 2 and 3), the levels of IFN-γ were higher than those in healthy gingiva. ^*Significant difference between Groups 1 and 3 (P < 0.05). Group 1: healthy gingiva from systemically healthy individuals, Group 2: inflamed gingiva from patients with chronic periodontitis, Group 3: inflamed gingiva from patients with chronic periodontitis and type 2 diabetes mellitus.

Figure 3

(A) Tissue inhibitor of matrix metalloproteinases-2 (TIMP-2) western blot analysis showing 4 representative samples in each group. TIMP-2 levels were quantified on the basis of β-actin levels. TIMP-2 corresponding to molecular weight 21 kDa was shown to be expressed in all samples including healthy gingiva. The expression levels of TIMP-2 were higher in patients with type 2 diabetes mellitus (DM) than in control healthy subjects. (B) Graphics showing the average amounts (ratio of TIMP-2/β-actin) and standard deviation of TIMP-2 level in Groups 1-3. In the inflamed gingiva (with or without diabetes, Groups 2 and 3), the levels of TIMP-2 were higher than those in healthy gingiva (P < 0.05). ^*Significant difference between Groups 1 and 3 (P < 0.05). ^†Significant difference between Groups 1 and 2 (P < 0.05). Group 1: healthy gingiva from systemically healthy individuals, Group 2: inflamed gingiva from patients with chronic periodontitis, Group 3: inflamed gingiva from patients with chronic periodontitis and type 2 DM.