Sustained Topical Delivery of Insulin From Fibrin Gel Loaded With Poly(Lactic- Co-Glycolic Acid) Microspheres Improves the Biomechanical Retention of Titanium Implants in Type 1 Diabetic Rats

Purpose The aim of this study was to determine whether local insulin delivery using a fibrin gel (FG) loaded with insulin/poly(lactic-co-glycolic acid) microspheres (FGIPM) improves the biomechanical retention of titanium implants in type 1 diabetic rats. Materials and Methods Rats were divided randomly into 8 groups: a group of healthy rats (no treatment), a group of diabetic rats (no treatment), and 6 groups of diabetic rats treated locally using carriers containing or not containing insulin. Rats received implants in the tibia and were allowed to heal for 4 or 8 weeks. Removal torque tests (RTQ) were performed to evaluate the biomechanical retention of the implants. Results In the diabetic control group, the mean RTQ values were significantly decreased compared with those for the healthy group. The local application of FGIPM increased the RTQ values in diabetic rats to the values found in the healthy rats at 8 weeks. The FG-treated group presented statistically significant higher mean RTQ values than the diabetic rats receiving no treatment. Conclusions Local insulin delivery using FGIPM ameliorated the biomechanical retention of titanium implants in type 1 diabetic rats and the FG had a beneficial effect.