The usefulness of basic fibroblast growth factor for radiation-exposed tissue.

A high dose of ionizing external radiation damage to the skin and soft tissue results in changes in function as well as in the general body condition. Once radiation surpasses the tissue safety or survival level, progressive alteration in the damaged tissue results in tissue loss and then flap loss. Local expression and action of stem cells or local growth factors in the irradiated tissue is mitigated, and external administration is sought to investigate the possibility of skin and soft tissue survival after an elevating flap. Basic fibroblast growth factor (bFGF) is primarily considered as a potent angiogenic growth factor. In burns, resurfacing with a dermal component is required, and bFGF stimulates wound healing and enhances human skin-derived mesenchymal stem cells under serum-free conditions in a dose-dependent manner. Thirty-five male, 4- to 8-week-old CLAWN miniature pigs received radiation exposure to assess the effectiveness of bFGF in terms of the progressive clinical course relevant to human skin and soft tissue. At 2 weeks following 10-Gy irradiation, tissue was preserved in the group receiving subcutaneous placement of a round-type tissue expander and bFGF. The expander plus bFGF group demonstrated significantly greater dermo-epidermal proliferation than the radiation alone, radiation plus bFGF, or expander plus radiation plus vehicle-solution groups, and new blood vessel formation was significantly increased in the expander tissue with bFGF after irradiation (p < 0.01). Electron microscopy revealed that tissue with expander and bFGF maintained more stable skin adnexae with preserved intact epidermis and dermis. Thus, bFGF improved and maintained the tissue viability after immediate irradiation in the skin and soft tissue.