Human Fat Grafting Alleviates Radiation Skin Damage in a Murine Model

Background: Autogenous fat grafting has been observed to alleviate the sequelae of chronic radiodermatitis. To date, no study has replicated this finding in an animal model. Methods: The dorsa of adult wild-type FVB mice were shaved and depilated. The dorsal skin was then distracted away from the body and irradiated (45 Gy). Four weeks after irradiation, 1.5-cc fat or sham grafts were placed in the dorsal subcutaneous space. Gross results were analyzed photometrically. The animals were euthanized at 4 and 8 weeks after fat or sham grafting and their dorsal skin was processed for histologic analysis. Results: Hyperpigmentation and ulceration were grossly improved in fat-grafted mice compared with sham-grafted controls. This improvement manifested histologically in a number of ways. For example, epidermal thickness measurements demonstrated decreased thickness in fat-grafted animals at both time points (20.6 ± 1.5 μm versus 55.2 ± 5.6 μm, p = 0.004; 17.6 ± 1.1 μm versus 36.3 ± 6.1 μm, p = 0.039). Picrosirius red staining demonstrated a diminished scar index in fat-treated animals at both time points as well (0.54 ± 0.05 versus 0.74 ± 0.07, p = 0.034; and 0.55 ± 0.06 versus 0.93 ± 0.07, p = 0.001). Conclusion: Fat grafting attenuates inflammation in acute radiodermatitis and slows the progression of fibrosis in chronic radiodermatitis.