Background: The aim of this study was to evaluate the protective effects of extracorporeal shock wave therapy (ESWT) against radiation injury in dermal fibroblasts and mouse skin.
Methods: Dermal fibroblasts were treated with ESWT (1000 impulses at 4Hz and 0.1mJ/mm2) after irradiation (20 Gy). Cell viability, cell migration, and mRNA and protein expression were measured. A total of 24 mice were used for an in vivo study. Mice were treated with ESWT (200 impulses at 4Hz and 0.25mJ/mm2) daily for 2 weeks after irradiation (45 Gy). At 8 weeks post-irradiation, dorsal skin was harvested for histopathologic examination and protein isolation.
Results: In dermal fibroblasts, the viability of irradiated cells was significantly increased after treatment with ESWT, relative to irradiated, nontreated cells (p=0.005). ESWT significantly reduced TGF-β1 protein expression at 48h post-irradiation (p=0.024). ESWT significantly increased cell migration at 24h post-irradiation (P =0.002). In mice, the irradiated skin treated with ESWT exhibited decreased collagen deposition compared with the control. ESWT significantly reduced TGF-β1 (p=0.001) and phospho-Smad3 (p=0.004) protein expression after irradiation. ESWT significantly decreased the number of TGF-β1- and α-SMA-positive cells after irradiation (p < 0.001).
Conclusions: Our study demonstrated that ESWT inhibited radiation-induced fibrosis by downregulating TGF-β1 expression. Therefore, ESWT may be a safe and effective candidate for the prevention of radiation-induced skin fibrosis.