Effect of rosiglitazone on alveolar bone loss in experimental periodontitis

Introduction: Recent evidences suggest that rosiglitazone, a PPAR-gamma agonist, reduces acute and chronic inflammation and attenuate periodontal inflammation; however the activation of this receptor could damage bone repair by decreasing the number of osteoblasts.

Objective: To investigate the effects of rosiglitazone (used as a blood-glucose lowering in hyperglicemic patients) administrated at therapeutical doses on alveolar bone-loss and some clinical biochemical markers in the rat model of ligature-induced periodontitis.

Materials and Methods: Periodontitis (P) was induced in male Wistar rats by placing a cotton ligature around the first lower molar tooth; sham animals (S) had the ligature immediately removed. Two weeks prior to periodontitis induction, and until the end of the experiments, half of the animals received rosiglitazone (1, 2 or 5 mg/kg/day; p.o.), forming three groups: P1, P2 and P5. The animals were sacrificed after 7 and 14 days of ligature placement and the jaws were removed for the radiographic measurement of alveolar bone loss. Serum and plasma samples were collected for analysis of clinical biochemistry markers (such as ALT, AST, gama-GT and bilirrubin for assessment of hepatic function, creatinine and urea for assessment of renal function, glucose and triglycerides).

Results: Independently of the treatment, periodontitis caused significant bone loss either on day 7 (p<0.01) or 14 (p<0.01). On day 14 after ligature placement, we observed a significant increase of AST activity in groups P2 and P5 in comparison with group P1 (p<0.05). No significant differences among the experimental groups were observed for the other biochemical markers.

Conclusions: We conclude that at therapeutical doses, rosiglitazone does not interfere with the alveolar bone loss secondary to periodontitis. The observed increases of gamma-GT and AST activity in rosiglitazone treated rats are, despite significant, of no clinical relevance and within the normal reference intervals for adult Wistar rats.

Supported by: CNPq e FAPESP