Stimulation of bone growth factor synthesis in human osteoblasts and fibroblasts after extracorporeal shock wave application

Nonunion is a common problem in Orthopedic Surgery. In the recent years alternatives to the standard surgical procedures were tested clinically and in vitro. Extracorporeal shock wave therapy (ESWT) showed promising results in both settings. We hypothesized that in target tissue cells from nonunions like fibroblasts and osteoblasts ESWT increases the release of bone growth factors. Fibroblasts and osteoblasts were suspended in 3 ml cryotubes and subjected to 250/500 shock waves at 25 kV using an experimental electrohydraulic lithotripter. After ESWT, cell viability was determined and cells were seeded at 1 x 10(5) cells in 12 well plates. After 24, 48, and 72 h cell number was determined and supernatant was frozen. The levels of growth factors FGF-2 and TGF-beta(1) were examined using ELISA. A control group was treated equally without receiving ESWT. After 24 h there was a significant increase in FGF-2 levels (p < 0.05) with significant correlation to the number of impulses (p < 0.05) observed. TGF-beta(1) showed a time-dependent increase with a peak at 48 h which was not significantly different from the control group. FGF-2, an important growth factor in new bone formation, was shown to be produced by human fibroblasts and osteoblasts after treatment with ESWT. These findings demonstrate that ESWT is able to cause bone healing through a molecular way by inducing growth factor synthesis.