Cytokines expression and bone loss in diabetic animals with periodontitis

Evidence suggests the existence of a positive correlation between diabetes mellitus and periodontal collapse.

Objectives: To evaluate the influence of diabetes mellitus on the progression of periodontal disease induced in rats, we evaluated alveolar bone loss and IL-1b, IL-6, TNF-a, and IFN-g tissue expression.

Methods: One hundred twenty-eight Wistar male rats were used in this study. They were divided into 4 groups of 32 rats each, as follows: Group I – control; Group II – diabetic; Group III – control with periodontal disease induced; and Group IV – diabetic with periodontal disease induced. After a streptozotocin-induced diabetic state was confirmed, a ligature was placed on the mandibular first molar teeth of rats in Groups III and IV. Eight animals of each group were killed at the experimental periods of 3, 7, 15, and 30 days after ligature placement. A digital image analyzer program was used for measurement of bone loss, and real-time PCR for cytokine expression. Statistical analysis was performed by ANOVA.

Results: The diabetic state lasted up to the end of the experiment in groups II and IV. Significant bone loss and significant cytokine expression (IL-6, IL-1b, and IFN-g) were observed in groups with induced periodontitis (Groups III and IV) at the 30th day (p < 0.05). Group III showed a significant expression of IL-1b at day 30 compared with the other groups (p < 0.05).

Conclusion: The induction of periodontal disease did not change the rats' hyperglycemic state; however, results suggest that the diabetes accentuated the severity of alveolar bone loss in the development of periodontal disease, being associated with an intense and sustained expression of pro-inflammatory and Th1-type cytokines during the course of experimental periodontitis.

Grants# Financial - FAPESP - 04/09849-0