Connective tissue alterations in irradiated mouse lung

Therapeutic radiation of the thorax for breast and lung carcinoma leads, in up to 10% of patients, to serious pulmonary complications which include pneumonitis and fibrosis. The molecular lesions leading to these pathological events are not presently understood. The role of connective tissue (CT) macromolecules, such as collagen subspecies, fibronectin and laminin in cell differentiation, tissue morphogenesis, wound healing and scar formation implicates their importance in radiation induced pathological lesions which may underly the clinical manifestations. Monospecific, polyclonal antibodies have been prepared to a variety of these CT species and are being employed in studies on the dose and time responses following irradiation of mouse lungs. Lungs of male LAF /sub 1//J mice were removed one year after doses of 0, 5, 7.5, 8.5 and 10 Gy of /sup 60/Co gamma rays. Two dimensional histograms generated by a video image digitizing system which scans fluorescently stained lung tissue sections reveal a dose dependent increase in type I lung collagen. The findings suggest that increased type I collagen is associated with radiation fibrosis of lung and that video image digital analysis of fluorescently stained tissue sections will be a useful tool to explore the role of extracellular matrix species in the radiation pathology of normal tissues