Radiation Injury in Rat Lung: I. Prostacyclin$({\rm PGI}_{2})$Production, Arterial Perfusion, and Ultrastructure

• Published in: Radiation research 1983-11, Vol.96 (2), p.284-293
• Main Authors: Chung-hsin Ts'ao, Ward, William F., Port, Curtis D.
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Biological effects of radiation; Endothelium; Epoprostenol - biosynthesis; Epoprostenol - radiation effects; Fibroblasts; Fundamental and applied biological sciences. Psychology; Gamma Rays; Ionizing radiations; Irradiation; Lung - metabolism; Lung - radiation effects; Lung - ultrastructure; Lungs; Male; Microscopy, Electron; Perfusion; Platelet aggregation; Platelets; Prostaglandins; Pulmonary alveoli; Pulmonary Artery - radiation effects; Radiation injuries; Radiation Injuries, Experimental - metabolism; Radiation Injuries, Experimental - pathology; Rats; Rats, Inbred Strains; Time Factors; Tissues, organs and organisms biophysics
• ISSN: 0033-7587; 1938-5404
• DOI: 10.2307/3576211

Pulmonary prostacyclin$({\rm PGI}_{2})$production, arterial perfusion, and ultrastructure were correlated in rats sacrificed from 1 day to 6 months after a single exposure of 25 Gy of gamma rays to the right hemithorax. PGI2production by the irradiated lung decreased to approximately half the normal value 1 day after irradiation (P < 0.05), then increased steadily throughout the study. By 6 months postirradiation, the right lung produced two to three times as much PGI2as did either shielded left lung or sham-irradiated lungs (P < 0.05). Perfusion scans revealed hyperemia of the right lung from 1 to 14 days after irradiation. From its peak at 14 days postirradiation, however, perfusion of the irradiated lung decreased steadily, then reached a plateau from 3 to 6 months at less than half that in the shielded left lung. Electron micrographs of the right lung revealed perivascular edema from 1 to 30 days after irradiation. The right lung then exhibited changes typical of radiation pneumonitis followed by progressive interstitial fibrosis. Platelet aggregates were not observed at any time. Thus, decreased PGI2production is an immediate but transient response of the lung to radiation injury. Then from 2 to 6 months after irradiation, the fibrotic, hypoperfused lung produces increasing amounts of the potent vasodilator and antithrombotic agent, PGI2. Pulmonary PGI2production and arterial perfusion are inversely correlated for at least 6 months after hemithoracic irradiation.