Studies on angiogenesis and endothelial cell apoptosis in radiation-combined wound healing in Wistar rats

Objective: To study the changes and significance of angiogenesis and endothelial cell apoptosis in radiation-combined wound healing. Methods: Wistar rats were wounded and then local irradiation was performed immediately with a dose of 25 Gy 60Co γ-rays in the irradiation wound group. Tissue specimens were obtained at 2, 5, 10, 15, 21 and 28 days after injury and angiogenesis and apoptosis of endothelial cells were investigated by means of LM, EM and in situ terminal labelling. Results: In the non-irradiation wound group, angiogenesis began from day 2 and the capillary number reached its peak on day 10 and decreased on day 15 after injury when the endothelial cells occurred apoptosis and scarcely necrosis. In the irradiation wound group angiogenesis began on day 5 when endothelial cells occurred apoptosis. The capillary number reached its peak on day 15 and decreased on day 21 after injury when endothelial cells occurred both apoptosis and necrosis. Conclusions: Radiation may delay the angiogenesis in wound healing, induce apoptosis of endothelial cells earlier and delay the peak of the capillary number. That radiation may delay the angiogenesis is one of reasons in delay of wound healing by radiation