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

Zhang L, Li X, Bi L‐J. Alterations of collagen‐I, MMP‐1 and TIMP‐1 in the periodontal ligament of diabetic rats under mechanical stress. J Periodont Res 2011; 46: 448–455. ©2011 John Wiley & Sons A/S 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.