Cell-Cell Matrix Interactions in Induced Lung Injury: I. The Effects of X-Irradiation on Basal Laminar Proteoglycans

The lungs of male ${\rm LAF}_{1}/{\rm J}$ mice were locally irradiated with graded doses of radiation ranging from 5 to 13 Gy. The animals were sacrificed at 1 hr, 1 day, 1 week, 4 weeks, and 12 weeks postirradiation (PI), fixed with Ruthenium Red/Triton X-100 for demonstration of basal laminar anionic sites, and processed for electron microscopy. Sham-irradiated (0 Gy, 0 time) and untreated control groups were also processed. Sections of lungs were examined ultrastructurally and changes in both alveolar and capillary basal laminar anionic sites quantitated. A marked decrease in the number of basal laminar anionic sites was noted 1 hr PI in both alveolar and capillary basal laminae at all dose levels. The decline continued to 1 week for doses of 13 Gy and more gradually to 4 weeks following doses of 5 and 9 Gy, when the number of sites began to increase. By 12 weeks animals receiving 13 Gy were approaching normal levels while those receiving 5 or 9 Gy remained subnormal. The potential effects of the loss of proteoglycans with radiation on lung basal laminar permeability and cell-extracellular matrix interactions are discussed.