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EFFECTS OF ACUTE EXPOSURE TO CONCENTRATED AMBIENT PARTICULATES ON CARDIOPULMONARY, THERMOREGULATORY, AND BIOCHEMICAL PARAMETERS IN OLD SPONTANEOUSLY HYPERTENSIVE RATS
Citation:
Nolan, J. P., D. W. Winsett, U P. Kodavanti, M. Schladweiler, D L. Costa, W P. Watkinson, AND L. B. Wichers. EFFECTS OF ACUTE EXPOSURE TO CONCENTRATED AMBIENT PARTICULATES ON CARDIOPULMONARY, THERMOREGULATORY, AND BIOCHEMICAL PARAMETERS IN OLD SPONTANEOUSLY HYPERTENSIVE RATS. Presented at American Thoracic Society, Seattle, WA, May 16-21, 2003.
Description:
EFFECTS OF ACUTE EXPOSURE TO CONCENTRATED AMBIENT PARTICULATES ON CARDIOPULMONARY, THERMOREGULATORY, AND BIOCHEMICAL PARAMETERS IN OLD SPONTANEOUSLY HYPERTENSIVE RATS. JP Nolan1, LB Wichers2, DW Winsett1, UP Kodavanti1, MCJ Schladweiler1, DL Costa1, and WP Watkinson1. 1US EPA, ORD/NHEERL/ETD/PTB, Research Triangle Park, NC; 2UNC School of Public Health, Chapel Hill, NC
Epidemiological studies have demonstrated a slight but consistent association between exposure to daily patterns of ambient particulate matter (PM) and increased morbidity and mortality. These effects appear to be especially pronounced in older compromised individuals. To further examine this relationship, we exposed old, Spontaneously Hypertensive rats (11 mon) to Concentrated Ambient Particulates (CAPs) from Research Triangle Park (RTP), NC. Rats (n=16) were implanted with radiotelemeters capable of monitoring electrocardiogram, heart rate (HR), and core temperature (Tco). Animals were divided into two equal groups and exposed (4h/d?3d) via nose-only inhalation to either CAPs or filtered air. Exposure concentrations ranged from 800?1225 g/m3. Telemetered rats were monitored throughout the experimental time period (5-min intervals; 4d preexposure?1d postexposure) and ventilatory function was examined (Buxco Electronics) daily (10-min duration; 1d preexposure?1d postexposure). At 24h postexposure, rats underwent bronchoalveolar lavage (BAL) and the BAL fluid was examined for biochemical indices of pulmonary injury and inflammation. Both groups showed similar responses ( HR, Tco) during exposure which were likely an artifact of the nose-only methodology. Despite the combination of two potential attributes of susceptibility (hypertension, advanced age), the above effects were small compared to those of previous studies that employed higher levels of relatively toxic model emission PM. These studies 1) suggest that RTP PM may be relatively innocuous compared to that of other locales, and 2) demonstrate the difficulties of confirming the results of large epidemiological studies with empirical toxicology. (Abstract does not represent USEPA policy. This research was supported in part by EPA CT826513.)