Expression of several growth factors and their receptors during the formation and development of acute radiation-induced skin ulcers and their effects on ulcer healing: an experimental study

Objective: To study the expression of several growth factors and their receptors during the formation and development of acute radiation-induced skin ulcers, and their effects on ulcer healing. Methods: Female Wistar rats were used, and a model of simple skin wounds was made. Another rat model which was locally irradiated with 60Co γ-rays was used, and the pathological changes were observed for 55 days. Immunohistochemistry, in situ hybridization and image analysis were performed to examine EGF, bFGF, VEGF, PDGF-B, TGF-β1 and their receptors in the tissue of radiation skin ulcers. Results: Skin ulcers were found on day 14 after irradiation, and they enlarged and deepened gradually during the observation period. In the irradiated skin, especially in the epidermal cells, fibroblasts and vascular endothelial cells of the ulcer beds, the expression of EGF, bFGF, VEGF, PDGF-B, TGF-β1 and their receptors was higher than that in normal skin, but their expression was suppressed in the ulcer beds as compared with that in the surgical wound beds. The expression of TGF-β1 and TGF-βR1 was elevated in the irradiated skin and was not inhibited in the cells of radiation ulcer beds as compared with that in the simple wound beds. Conclusion: After irradiation, the decreased expression of some growth factors and their receptors in the local skin tissue may play an important role in the formation, development and non-healing mechanism of radiation skin ulcers