Alveolar bone remodeling during tooth movement in type i diabetic rats treated or not with insulin and metiformin: analysis by micro-CT and histomorphometry

Abstract

Diabetes mellitus type 1 produces changes to the internal bone structure, increasing the risk of fracture and slowing the pace of repair/remodeling bone. Insulin plays a crucial role in the treatment of type 1 diabetes, moreover, interact with osteocalcin hormone OC by its receptor (IR) in the osteoblast membrane, contributing to the stability of bone density, followed by a significant decrease in bone resorption. The association of metformin with insulin in type 1 diabetic patients has collaborated with decrease of the dose of insulin administered, weight control and reduction in Low Density Lipoproteins. Our purpose is to verify the effects of insulin in the alveolar bone and its combination with Metformin during orthodontic tooth movement in diabetic rats. 45 rats will receive a single injection of Streptozotocin 50mg/Kg. 7 days later, the rats will be randomly divided into untreated group (ST-DM1, n=15) that will receive saline only, Diabetic + insulin (TINDM1, n=15) that will receive daily 6 U of insulin, diabetic + insulin + metformin (TIN+MFDM1, n = 15) that will receive daily 6 U of insulin and 150 mg/kg metformin. After 14 days of induction, will be held the mesial movement of the upper right 1st molar from a closed nickel-titanium spring that exercise 50g of force. On days 3, 7 and 14 after the spring installation 5 hemimaxillas/group will be collected to be evaluated by micro-CT, histomorfometry and cytochemistry. Micro-CT assess whether treatment with insulin as metformin acts positively associated with the amount of tooth movement and alveolar bone density and microarchitectural. By histomorphometry will check the result Diabetes periodontal changes during tooth movement and the possible positive effect of insulin associated or not with metformin on bone remodeling. By cytochemical quantify the number of periodontal tissue osteoclástos/mm2 checking whether treatments with insulin or insulin / metformin interfere positively in controlling the formation / osteoclastic activity during alveolar bone remodeling. All quantitative results are subjected to statistical analysis using Statistica 10 software, with 5 % significance level. (AU)