[en] Current oncological practice frequently uses pre-, intra- or post-operative radiotherapy/chemotherapy. Before such treatment can begin it is imperative to establish that satisfactory wound healing will occur. Many previous studies have examined the response of wound healing to ionizing and non-ionizing radiation. In general, clinical and experimental reports indicate that ionizing radiation produces poor to difficult healing of wounds, and can even prevent healing altogether. It is for this reason that the effect of radiation on wound repair has been a long standing concern for surgeons, radiotherapists and radiobiologists. Electron irradiation produces large differences in depth-dose distributions. This enables the delivery of a constant maximal dose throughout the superficial layer of tissue, for example, the total depth of skin, with less damage in deeper tissue layers, compared to that produced by the use of electromagnetic radiation such as X-rays. It is for this reason that electron beam irradiation has been selected as a radiation source for radiation of the graft bed. To date there have been few morphological examinations of the effect of electron radiation on the healing of skin wounds in rats. A review of the literature shows no information on the use of radiation of the graft bed in skin graft surgery. In the present work the processes involved in wound repair in response to radiation were studied, morphologically, using two experimental models, incisional wounds combined with pre-operative radiation and skin autografts combined with radiation of the wound bed. In the latter case an unirradiated skin graft was surgically attached to an irradiated wound bed. Light microscopy (LM), backscattered electron imaging (BEI), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used as investigative tools. These repair processes include inflammation, re-epithelialization, re-formation of the dermo-epidermal junction, re-vascularization and granulation tissue formation and remodelling. Two basic and important questions addressed by this study were whether ionizing irradiation influences individual processes in wound healing, and whether or not radiation of the graft bed is compatible with cutaneous surgery. In these two experimental models, pre-wounding radiation and radiation of the graft bed partially depressed the inflammatory reaction in response to injury, and also reduced the deposition of fibrin and presence of tissue exudate. Following this initial event, there was a delay but not a prevention of re-epithelialization and reformation of the dermo-epidermal junction (DEJ). The present study also revealed early morphological changes in the microvessels of the irradiated wound bed and in the granulation tissue, indicating an early effect on angiogenesis. This investigation also focused on the effects of radiation on granulation tissue formation and extracellular matrix (ECM) remodelling. The results demonstrated that ionizing radiation caused a decrease in the presence of fibroblasts and in the extent of granulation tissue formation and ECM remodelling. In the study of incisional wounds with pre-operative radiation treatment, granulation tissue depth and volume were decreased up to 7 days post-wounding, but were restored to around the sham-irradiated wound values by day 14. In the study of skin graft repair as affected by radiation of the graft bed, two parameters, diameter and density of collagen fibrils in the granulation tissue were examined quantitatively. The findings showed that collagen fibril diameter was significantly reduced throughout the experimental period, by comparison with that found in the grafted only group. However no differences were detected for collagen fibril density between the two groups by 2 weeks post-grafting. This work concludes that pre-wounding and wound bed radiation slows down wound healing, but does not prevent it, at single dose levels of 9.6 Gy and 10 Gy. Since this study is the the first to investigate skin grafting combined with radiation of the wound bed, it is noteworthy that while this procedure induces a delay in the healing of skin autografts, it does not appear to present any obvious clinical complications during early healing stages, at least in the rat model. Further irradiation studies in this area should be undertaken at higher dose levels. (author)