1983 Volume 18 Issue 1 Pages 35-41
Daily 3-hour exposure of rats to 1.0 ppm O3 for 30 consecutive days resulted in an increase in pulmonary flow resistance which was suspected to be dependent primarily on the narrowing of relatively large airways. The suggestive reduction in lung distensibility was also observed, but a change in pulmonary static volume-pressure curve indicative of altered refractive forces of alveoli was not observed. Light-microscopically, a marked formation of the mucosal infolding was noticed particularly at larger to middle-sized bronchi, and the increased secretion frequently covered the inner surface of the mucosa at the top of infolding: thus, their effective caliber appeared to be narrowed. No significant change in the resistance of peripheral airway was detected by the present technique in the same animals. Daily 3-hour exposure to 1.0 ppm O3 for 14 consecutive days resulted in no significant change in the functional measurements.
