The role of vascular injury in the radiation response of mouse lung.

A frequent and often lethal consequence of lung irradiation with doses of greater than X-rays is pneumonitis which occurs 2-6 months after exposure. If recovery takes place, a diffuse pulmonary fibrosis may then develop, possibly leading to respiratory failure (Gross, 1981). In general, the radiation response of tissues is ascribed to cell death which occurs when irradiated cells attempt to divide. Any delay between irradiation and tissue response may be related to the turnover of the target cells (Withers et al., 1980). In lung, the three main cell types which maintain lung function, i.e. alveolar epithelial, capillary connective tissue all have slow cell turnover rates and therefore damage in any of these may underly the delayed response of lung to irradiation.