Effect of Nerve Growth Factor on Osseointegration of Titanium Implants in Type 2 Diabetic Rats

Purpose: Compared with the general population, a poorer quality of bone-implant osseointegration occurs and at a higher failure rate in patients with type 2 diabetes mellitus. The aim of this study was to analyze the effects of local injection of nerve growth factor at the bone-implant interface after implantation in type 2 diabetic rats. Materials and Methods: Goto-Kakizaki (GK) rats (n = 30) were used as a model of type 2 diabetes mellitus, and Wistar rats were used as a control (n = 15). GK rats were assigned randomly into two groups (n = 15/group): the diabetes mellitus group (saline only) and the nerve growth factor group (received nerve growth factor treatment). One titanium implant was placed in each rat's left tibia. Immediately postoperatively, nerve growth factor group rats were injected with nerve growth factor (0.4 μg/ day) intramuscularly around the implant, daily for 7 days. Diabetes mellitus and control group rats received normal saline in an identical manner. Rats were sacrificed at 2, 4, and 8 weeks following implant surgery. Results: Traditional light and confocal laser scanning microscopy were used on nondecalcified sections to investigate fluorochrome labeling changes and histologic features of bone adjoining the implants. Bone-toimplant contact and bone volume percentage in the diabetes mellitus group were significantly less than in the control and nerve growth factor groups, with no statistically significant differences between the control and nerve growth factor groups. Confocal laser scanning microscopy showed a significant increase in marked bone around the nerve growth factor group implant at 4 weeks (P < .01) and 8 weeks (P < .05) compared with the diabetes mellitus group. Conclusion: This study showed that local injection of nerve growth factor could improve implant-bone osseointegration in diabetic rats and may have important clinical implications.