| Abstrakt: |
We investigated the relationship of age to rat lung collagen synthesis in response to ozone (O) exposure. Specific pathogen-free Sprague-Dawley male rats 24, 30, 45, 60, 94, 182 and 365 days old were exposed to either 0.8 ±.05 ppm O for 3 days or to 0.8 ± 0.5 ppm O for 3 days followed by 4.0 ±.2 ppm O for 8 hours and 60 days recovery in air. A matched number of rats from each age group received filtered air and served as controls. Lung dry weight, protein content, hydroxyproline content, C proline incorporation and C hydroxyproline formation were determined in control and exposed rat lungs. Rats exposed to 0.8 ppm O for 3 days had greater dry weight, protein content, incorporation of C proline, and formation of C hydroxyproline per lung relative to controls, with the greatest changes occurring in rats older than 60 days. Rats 24 and 94 days old, exposed to 0.8 ppm O for 3 days followed by 4.0 ppm O for 8 hours and 60 days recovery in air, had greater lung collagen content than controls: 50% and 80%, respectively. These results suggest that collagen synthesis was increased following O exposure and that the degree of change was influenced by age in the rat. Age, therefore, may be an important factor in the lung's response to pulmonary injury. [ABSTRACT FROM AUTHOR] |
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