Potential mechanism for osseointegration of dental implants in Zucker diabetic fatty rats

Our aim was to investigate the impact of diabetes mellitus and different durations of glycaemic control on early osseointegration of dental implants, and to explore possible mechanisms by measuring the expression of integrin α5β1 and fibronectin in bone around the implant. We divided 33 male Zucker diabetic fatty (ZDF) rats aged 3 months into 3 groups. The first group comprised diabetic rats with dental implants (controls); the second group was treated with insulin and implants were placed simultaneously (exenatide alone group); and the third group was treated with insulin until the serum glucose was at a constant concentration (< 16 mmol/L), and implants were then inserted (exenatide+normal glucose group). Rats were killed 7, 14, 30, and 60 days after implants had been inserted. The expression of integrin α5β1 and fibronectin in bone around the implants was detected by immunohistochemical analysis in each group. The expression in the exenatide+normal glucose group was stronger than in the other 2 groups. Fourteen days after implantation, expression of integrin α5β1 in the exenatide alone group was significantly stronger than that in the control group (p=0.027), and 60 days after implantation the expression of fibronectin in the exenatide alone group was also significantly stronger than that among the controls (p=0.001). Both fibronectin and integrin α5β1 participate in the adhesion of osteoblasts and act as signals at the bone/implant interface. Diabetes interferes with the osseointegration of implants by deferring expression of fibronectin and integrin α5β1.