The Effect of Local Melatonin Application on Bone Fracture Healing in Rat Tibias

<i>Background and Objectives:</i> This study aimed to histologically evaluate the effects of local melatonin application at different doses on bone fracture healing. <i>Materials and Methods:</i> Thirty rats were divided into three groups, with ten rats in each group. In the control group (<i>n</i> = 10), a fracture line was created in the tibial bones, and fracture osteosynthesis was performed without any additional procedure. In the local melatonin dose 1 (MLT D-1) group (<i>n</i> = 10), a fracture line was created in the tibial bones, and 1.2 mg of lyophilized powder melatonin was applied locally before fracture osteosynthesis. In the local melatonin dose 2 (MLT D-2) group (<i>n</i> = 10), a fracture line was created in the tibial bones, and 3 mg of lyophilized powder melatonin was applied locally before fracture osteosynthesis. After a 12-week healing period, all subjects were sacrificed, and tibial bones were collected for histomorphometric analysis. <i>Results:</i> The percentage of bone formation was significantly higher in the MLT D-1 and MLT D-2 groups than in the control group. There was no statistically significant difference between the MLT D-1 and MLT D-2 groups. <i>Conclusions:</i> In conclusion, the study demonstrated that local melatonin application supports bone fracture by increasing bone formation, although different doses of melatonin did not lead to significant variations in fracture healing.