Effects of leptin on femoral fracture in rats

In this study, our objective was to evaluate effects of leptin on fracture healing in rats. Seventy two male SpragueDawley (SD) rats were randomized into 3 groups. Standardized femoral fractures were created in all the rats. Group A was treated with 1 mL normal saline (NS), group B with 0.3 μg/kg leptin in 1 mL NS, and group C with 0.5 μg/kg leptin in 1 mL NS for 2 weeks intraperitoneally. Each group was divided into three subgroups including 8 rats for evaluation at 2, 4 and 8 weeks. Radiological evaluation showed that callus formation of group B and C was all significantly higher than group A at 8 weeks (P = 0.04 and P = 0.013, respectively). There was no statistically significant difference in fracture healing between group B and group C at 8 weeks (P = 0.197). Histological evaluation revealed fracture healing of group B and C was better than group A at 4 weeks (P = 0.01 and P = 0.002, respectively) and 8 weeks (P = 0.008 and P = 0.003, respectively). Micro-computed tomography (Micro-CT) analysis demonstrated that greater amounts of bony callus and evidence of bone fusion were observed in group B and C at 4 weeks (P = 0.02 and P = 0.04, respectively) and 8 weeks (P = 0.005 and P = 0.001, respectively) compared to group A. Group C also had better fracture healing than group B at 8 weeks (P = 0.01). In conclusion, leptin has a positive effect on rat femoral fracture healing.