Structural and biochemical effects in lungs of Japanese quail following a 1-week exposure to ozone

The effect of ozone inhalation on birds was investigated. Japanese quail were exposed continuously to 0, 0.3, 1.0, and 3.0 mg/m3 ozone (0, 0.15, 0.50, and 1.50 ppm, respectively) for 7 days. Pulmonary effects were determined by light and electron microscopy as well as by biochemistry. Focal areas of hemorrhages were noticed in the birds exposed to 1.0 mg/m3 ozone. Additional effects after exposure to 1 mg/m3 included loss of cilia in trachea and bronchi, an inflammatory response, and necrosis of air capillary epithelial cells. Following exposure to 3 mg/m3 many atria of tertiary bronchi were completely obstructed by extensive hemorrhages, metaplasia of atrial wall cells, and hypertrophy of smooth muscle cells. Lung biochemistry data revealed that in the 3 mg/m3 group lactate dehydrogenase, glucose-6-phosphate dehydrogenase, and glutathione reductase activities were significantly increased. In the 0.3 and 1.0 mg/m3 exposure groups no effects on lung antioxidant enzymes were observed. In conclusion, Japanese quail appear to respond to ozone exposure in a different way than mammals. Since no signs of repair in air capillary epithelium after 7 days of continuous exposure were observed, the quail seems to lack the morphological and biochemical repair ability as is observed in mammals. Therefore, more research of the effects of ozone on birds seems to be necessary, both from a mechanistic and an ecological point of view.