The effect of local and systemic irradiation on impairment of wound healing in mice.

These experiments were designed to quantify the impact of local or systemic irradiation on the healing of full-thickness skin wounds in mice. Mice received total-body hemibody, or skin irradiations, prior to wounding. Wound tensile strength measured on day 14 was used as an end point. The dose to achieve an isoeffect of 40% of the tensile strength of the wounded controls was 13 Gy less for the total-body exposure than for local skin irradiation. Histological observation showed markedly fewer inflammatory cells in the wounded skin sections from total-body and hemibody-irradiated mice compared with those receiving only skin irradiation. These data demonstrate that the healing response in irradiated skin is dependent upon the extent of hematopoietic suppression and that at low doses this determines the outcome rather than damage to fixed target cells such as dermal fibroblasts, which are relatively resistant to radiation.