Alterations of collagen-I, MMP-1 and TIMP-1 in the periodontal ligament of diabetic rats under mechanical stress

Background and Objective: The present study assessed effects of hyperglycemia on production of proteins involved in remodeling of the periodontal ligament under mechanical stress. Material and Methods: Forty-eight Sprague-Dawley rats were randomly divided into the following two groups: nondiabetic (ND) and diabetes induced (DI; n = 24 each group). Diabetes was induced in the DI group by a single dose of streptozotocin, and saline solution was injected in the ND group. Rats were killed 1-14 d after induction of mechanical pressure (50 g) on the first upper left molar. Alterations of collagen type I (Col-I), MMP-1 and TIMP-1 in the upper left periodontal ligament of these rats were measured immunohistochemically and compared with those on the contralateral side of the same rat (control; no force induction). Results: The DI group showed a decrease in Col-I and an increase in MMP-1 compared with the ND group. Both Col-I and MMP-1 increased in both groups, whereas TIMP-1 was decreased following mechanical pressure. The DI group exhibited a longer duration of increased MMP-1 and MMP/TIMP ratio compared with the ND group. Conclusion: Diabetes affects proteins involved in remodeling of periodontal ligament during mechanical pressure. This may delay the reconstruction and remodeling of periodontal ligament in diabetic individuals.