Response of rat lung to N-hexane and whole-body x-irradiation given solely or combined.

Biochemical, cytological and morphological studies in Wistar male rats. For N-hexane inhalation treatment, dynamic exposure chambers maintaining a concentration of 5,500 mg/m3 over 5 hours per day were used for 8 days. Immediately there after, the animals were given a single whole-body exposure to 4 Gy X-rays. Bronchoalveolar lavage fluid (BALF) was obtained from removed lungs. Lung homogenates were prepared subsequent to intracapillary lung perfusion via the right cardiac ventricle. Short-term n-hexane inhalation treatment was found to increase BALF total cell counts, predominantly alveolar macrophages (AM); elevated activities in lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) evidenced injury affecting type I and type II pneumocytes over early post-treatment times. Whole-body irradiation alone moderately decreased AM numbers in respiratory pathways. Exposure to both agents combined resulted in depressed activity of a major antioxidant enzyme, superoxide dismutase, and diminished contents of nonprotein sulfhydryl groups in the lungs. Most of the endpoints recorded underwent greater change in the case of combined treatment, indicating synergistic action of n-hexane and ionizing radiation with regard to the biological effects studied.