Effect of60Co irradiation and trace element zinc on implant-bone fusion

doi:10.3969/j.issn.2095-4344.2015.30.009

Abstract：BACKGROUND:Zinc supplementation can accelerate implant-bone fusion. OBJECTIVE:To observe the effect of 60Co irradiation and trace element zinc on implant-bone fusion. METHODS:A total of 36 adult male rabbits were involved. One piece of titanium implant was placed into the proximal end of the rabbit's bilateral tibial heads respectively to set up the animal model with titanium implants. Then the animals were randomly divided into four groups. Twenty-four hours after implantation, 10 g/L zinc sulfate was administered intramuscularly to the animals in the zinc supplement group at the dose of 4 mg/kg, once per day; 9 g/L normal saline was administered intramuscularly to the animals in the control group at the dose of 4 mg/kg, once per day. The animals in the 60Co irradiation group received 60Co irradiation at 2, 4, 6 days at the dose of 15 Gy per day, and 24 hours after implantation, 9 g/L normal saline was administered intramuscularly at the dose of 4 mg/kg, once per day; while those in the 60Co irradiation and zinc supplement group received 60Co irradiation at 2, 4, 6 days at the dose of 15 Gy per day, and 24 hours after implantation, 10 g/L zinc sulfate was administered intramuscularly to the animals at the dose of 4 mg/kg, once per day. The animals were kiled at 1, 4, 12 weeks after treatment. Stereomicroscope was used to observe the histomorphology on the implant-bone interface. RESULTS AND CONCLUSION:Compared to other groups, at the same time, more fibroblasts and fibrous fusion were observed around the implants from the 60Co irradiation group while less bone tissue, especialy mature bone tissue, was observed. On the contrary, at the same time, the surfaces of the implants from the zinc supplement group showed more osteoblasts and bone fusion. Mature bone tissue was observed around the implants at the 4th week after implantation indicating that zinc supplement can accelerate the new bone formation on the implant-bone interface at 1-4 weeks after treatment to facilitate the fusion between the implant and bone. The implants from the 60Co irradiation and zinc supplement group showed more bone fusion than those from the 60Co irradiation group at the 4th and 12th weeks, indicating that after 60Co irradiation, zinc supplement stil can promote the fusion between the implant and bone. Taken together, these results demonstrate that the appropriate amount of zinc supplemented after irradiation therapy can aleviate the negative effects of irradiation on the implant-bone fusion.