Effect of mechano growth factor on radial fracture healing in rabbits / 中国组织工程研究

ABSTRACT

BACKGROUND: Current research of mechano growth factor (MGF) mainly focuses on the muscles and nerve damage and repair, and it has bean confirmed that MGF can promote muscle cell hypertrophy and nerve repair significantly. Regarding its role in fracture healing is unclear. OBJECTIVE: To investigate the effect of MGF on radial fracture healing in rabbits. METHODS: By using random digital table method, 12 New Zealand rabbits were divided into 3 groups blank control group, low-dose MGF group and high-dose MGF group. The models with 5 mm bone defect were produced in the middle of the left radius in rabbits. At 3 days after the surgical operation, the defective areas were given 0.2 mL PBS or 0.2 mL MGF (0.36 and 0.72 g/L) injected into the ends of fracture areas, respectively, once per day for continuous 5 days. At 4, 6, 8 weeks after operation, X-ray photography was used to evaluate the healing of fracture, and the histological examinations were performed at the 8~(th) weak to observe the call morphology at the fracture lesion. RESULTS AND CONCLUSION: At 1 day after operation, the activities of rabbits were reduced, with slightly reduced food intake, at 2 days they almost recovered to normal activities and diet. At 3 days, the surgical incision slightly swelled with a small amount of bleeding and without obvious signs of infection. All 12 rabbits entered the final analysis. X-rays showed that two fracture ends have basically combined in the high-dose MGF group at 4 weeks post-surgery, cortical bone was continuous and fracture lines were unclear. At 6 weaks the bone medullary cavity almost run through and fully run through at 8 weeks. The healing time in the high-dose MGF group was remarkably shorter than that in blank control group and low-dose MGF group, the healing was in high quality. At 8 weeks after operation, a large number of osteoid tissues were observed in the blank control group, a small amount of woven bone formed, at a transition period from the fibrous bone callus to the bony bone callus; a large number of woven bone formed inthe low-dose MGF group, at bony bone callus period; in the high-dose MGF group, a large number of woven bones converted into mature lamellar bone, at the callus rebuilding phase, which was consistent with imaging results. It is indicated that MGF can accelerate fracture healing significantly in a rabbit model and shows a dose-dependent manner in a certain range.