The role of fibroblasts in bone healing with extracorporeal shock wave treatment / 中华物理医学与康复杂志

ABSTRACT

Objective To investigate the role of fibroblasts in nonunion fracture healing using extracorporeal shock wave(ESW) treatment. Methods Thirty healthy rabbits were selected to make the models of non-union fractures of the right tibias, which were then held apart by external fixation. 12 weeks after the operation, hypertrophic non-unions were confirmed in 27 of the rabbits by radiography. These 27 were divided randomly into a treatment group and a control group. The test animals were treated with ESW under general anaesthesia. The two ends of the nonunion fracture were shocked 1 000 times at 0.54 mJ/mm2 and a frequency of 60 times/minute. The nonunions of the control group were treated with external fixations only. Histological examination and transmission electron microscopy(TEM) were conducted after 2 and 6 weeks. Standardized radiographs were taken after 12 weeks of the shock wave treatment. Results ESW induced microfractures, which initiated the healing process of the nonunionfractures. X-rays showed that 8 of the 9 fractures of the treatment group had healed after 12 weeks of EWS treatment, but only 3 of the 9 in the control group had healed. Statistical analysis showed that this difference was significant at the 5% level. After 2 weeks of ESW treatment, TEM showed many collagen fibers around the fibroblasts in the treatment group, with characteristic and periodic transverse lines. This indicated that the fibroblasts had been secreting collagen fibers as osteoblasts. Six weeks later, osteoblasts and fibroblasts had formed bone lacunes, and they had become osteocytes. However osteogenetic activates were not found in the control group. Conclusions Fibroblasts are activated by ESW to better form bone tissue. This process plays an important role in rebuilding broken bones.