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AGE AND STRAIN INFLUENCES ON LUNG RESPONSES TO CONCENTRATED AIR PARTICULATES (CAPS) IN RODENTS
Citation:
Dye, J A., U P. Kodavanti, L. C. Walsh, M. Schladweiler, J H. Richards, J. Norwood, AND D L. Costa. AGE AND STRAIN INFLUENCES ON LUNG RESPONSES TO CONCENTRATED AIR PARTICULATES (CAPS) IN RODENTS. Presented at American Thoracic Society Conference, Atlanta, GA, May 17-22, 2002.
Description:
Asthma, an inflammatory airways disease, is an urgent health problem. Recent epidemiologic studies have demonstrated positive associations between ambient air particulate matter concentrations and daily respiratory morbidity ? including exacerbations of asthma. Of note, elderly individuals are experiencing some of the greatest increases in mortality from asthma. Therefore, in these studies, we evaluated the respiratory effects of CAPs exposure in both young adult (10 wk) and geriatric (15 mo) rats from the spontaneously hypertensive (SH) strain, a strain that commonly develops mild inflammatory lung disease in addition to systemic hypertension. Rats from the background WKY strain were used for comparison. Rats were exposed to either air or CAPS for 4 hr/day x 2 consecutive days. The chamber particle concentrations were 1400? 1800 g/M3. Bronchoalveolar or nasal lavage fluid (BALF or NALF) and lung samples were collected 20 hr later. In air-exposed controls, biochemical analysis of BALF demonstrated that for many of the indices evaluated, relative to WKY rats, SH rats had consistently higher concentrations [e.g., albumin, total protein (TP), and lysozyme]. Furthermore, the magnitude of the strain differences increased with age. Similarly, SH rats had greater numbers of total cells in the BALF (largely due to increases in macrophages) and again these differences increased with age. Relative to these inherent strain- and age-related differences, CAPs-induced changes were negligible in the geriatric rats. In the young adult rats, CAPs exposure was associated with BALF increases in gamma-glutamyl transferase (GGT) and there were trends towards increases in albumin, TP, and neutrophils. In conclusion, although these geriatric rats developed greater changes in their BALF biochemical and inflammatory indices as a consequence of aging, advanced age alone did not predispose the rats to developing greater lung changes following exposure to concentrated ambient air particles from the central North Carolina airshed.
This abstract does not reflect US EPA policy.