Therapeutic potential of adipose stem cells in tissue repair of irradiated skeletal muscle in a rabbit model.

The repairing function and differentiation potency of adipose stem cells (ASCs) transplantation following skeletal muscle injury induced by radiotherapy are still not well defined. In this study, one side of the buttocks of 64 New Zealand white rabbits underwent irradiation and were randomly divided into an ASCs group [5×10(7) ASCs labeled with CM-Dil and suspended in 1 mL of phosphate-buffered saline (PBS), via intramuscular injection] and a PBS group (1 mL of PBS, via intramuascular injection). ASCs were isolated in New Zealand white rabbits in vitro, and migration of ASCs labeled with CM-Dil was observed after transplantation in vivo. A significant decrease of histological severity scoring was found in irradiated tissue obtained in the ASCs group compared with that in PBS group. Additionally, compensatory hyperplasia was noted after ASCs transplantation in the injured tissues. Moreover, ASCs could upregulate the expression of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) and promote the angiogenesis of the injured tissues. Interestingly, myofilament-like structures were identified in irradiated muscle cells after ASCs transplantation. We concluded that ASCs transplantation could repair the radiation-induced skeletal muscle injury. Its mechanism may be, at least partly, associated with the upregulation of VEGF and bFGF, angiogenesis, promoting the compensatory hyperplasia of muscle satellite cells, as well as the myogenic differentiation.