Vincent R, Vu D, Hatch G, Poon R, Dreher K, Guénette J, Bjarnason S, Potvin M, Norwood J, McMullen E
Environmental Health Directorate, Health Canada, Ottawa, Ontario, Canada.
Am J Physiol. 1996 Oct;271(4 Pt 1):L555-65. doi: 10.1152/ajplung.1996.271.4.L555.
Biological effects indicators in bronchoalveolar lavage fluid were studied in Fischer 344 rats of different ages after exposure to 0.4-0.8 ppm ozone for periods of 2-6 h on a single day or on 4 consecutive days. The magnitude of alveolar protein transudation induced by ozone was not different between age groups, but the interindividual variability of protein changes was higher in senescent (24-mo-old) rats. By comparison to juvenile (2-mo-old) and adult (9-mo-old) rats, senescent animals had higher increases of interleukin-6 (up to 10-fold higher) and N-acetyl-beta-D-glucosaminidase (NAGA; 2-fold higher) in lung lavage after ozone. Ascorbic acid was lower in lungs of senescent rats (one-half of juvenile values), and acute ozone exposure brought a further decrease in lung ascorbate. Whereas alveolar protein transudation was attenuated after ozone exposure on 4 days, persistent elevation of NAGA in senescent rats suggested only partial adaptation. Injection of endotoxin did not modify the patterns of effects. Incorporation of 18O-ozone into macrophages and surfactant was not different between age groups, indicating that the magnified biological responses in senescent rats were not dominated by differences in internal dose of ozone. The results indicate that senescent rats respond differently than juvenile and adult rats to lung injury.
研究了不同年龄的Fischer 344大鼠在单次暴露于0.4 - 0.8 ppm臭氧2 - 6小时或连续4天暴露于该浓度臭氧后的支气管肺泡灌洗流体中的生物学效应指标。臭氧诱导的肺泡蛋白渗出程度在各年龄组之间没有差异，但衰老（24月龄）大鼠中蛋白变化的个体间变异性更高。与幼年（2月龄）和成年（9月龄）大鼠相比，衰老动物在臭氧暴露后肺灌洗中的白细胞介素-6升高幅度更大（高达10倍），N - 乙酰 - β - D - 氨基葡萄糖苷酶（NAGA；升高2倍）。衰老大鼠肺中的抗坏血酸含量较低（为幼年大鼠值的一半），急性臭氧暴露使肺中的抗坏血酸进一步减少。虽然在4天的臭氧暴露后肺泡蛋白渗出减弱，但衰老大鼠中NAGA的持续升高表明仅部分适应。注射内毒素并未改变效应模式。各年龄组之间巨噬细胞和表面活性剂中18O - 臭氧的掺入没有差异，这表明衰老大鼠中放大的生物学反应并非由臭氧内部剂量的差异主导。结果表明，衰老大鼠对肺损伤的反应与幼年和成年大鼠不同。
