OZONE EXPOSURE, ADAPTATION, AND CHANGES IN LUNG ELASTICITY

In rabbits, the left lung (LL) was compressed by a unilateral pneumothorax to prevent ventilation while the right lung (RL) was exposed to ozone (O3) (2 ± 0.2 or 5± 0.4 ppm) for 3 hr. Following the exposure, the LL was reexpanded. One week later the lungs were exposed bilaterally to higher concentrations of O3 (16 ± 2.2 or 19 ± 0.4 ppm) for 3 hr. The animals were then killed and the two lungs were excised, weighed, and subjected to volume/pressure measurements. The previously exposed RL was found to be less edematous, but also less distensible than the paired LL. In addition, the LL showed increases in wet and dry weights below what would be expected from its single direct exposure to O3. The findings indicate that while the reduction in edema formation associated with adaptation or tolerance to O3 occurs mostly on a local basis, a part of the tissue response of the respiratory system to O3, as evidenced by the changes in weight of the LL, may be mediated systemically. The possible relation between the reduction in edema formation and altered distensibility of the RL is discussed. © 1979.