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EFFECTS OF SUBCHRONIC EXPOSURE TO CONCENTRATED AMBIENT PARTICULATES IN SPONTANEOUSLY HYPERTENSIVE RATS
Citation:
Watkinson, W P., J. P. Nolan, D. W. Winsett, U P. Kodavanti, M. Schladweiler, D L. Costa, AND L. B. Wichers. EFFECTS OF SUBCHRONIC EXPOSURE TO CONCENTRATED AMBIENT PARTICULATES IN SPONTANEOUSLY HYPERTENSIVE RATS. Presented at American Thoracic Society, Seattle, WA, May 16-21, 2003.
Description:
EFFECTS OF SUBCHRONIC EXPOSURE TO CONCENTRATED AMBIENT PARTICULATES IN SPONTANEOUSLY HYPERTENSIVE RATS. WP Watkinson1, LB Wichers2, JP Nolan1, DW Winsett1, UP Kodavanti1, MCJ Schladweiler1, and DL Costa1 1US EPA, ORD/NHEERL/ETD/PTB, RTP, NC; 2UNC SPH and Curriculum in Toxicology, Chapel Hill, NC
Numerous epidemiological studies have reported a robust correlation between the levels of ambient particulate matter (PM) and the incidence of morbidity and mortality, particularly among persons with cardiopulmonary disease. While some toxicological studies have demonstrated analogous effects in animals using model emission PM, these studies have been criticized for the relatively high concentrations and toxicity of the particles used. To investigate this phenomenon using a more environmentally-relevant protocol, we examined the effects of Concentrated Ambient Particulates (CAPs) from Research Triangle Park, NC in Spontaneously Hypertensive rats. Rats (n=8) were implanted with radiotelemeters capable of monitoring electrocardiogram, heart rate, blood pressure, and core temperature. Animals were equally divided into two groups and exposed (4h/d?2?3d/wk?9wk) via nose-only inhalation to CAPs. PM exposure concentrations ranged from 135?1600 g/m3. Telemetered rats were monitored (5-min intervals) throughout the experimental time period while ventilatory function was examined once daily (10-min duration) before, during, and after exposures. At 24h postexposure rats underwent bronchoalveolar lavage (BAL) and the BAL fluid was examined for biochemical indices of pulmonary injury and inflammation. There were no discernable differences between the two groups with respect to monitored telemetry parameters or BAL indices. It is likely that more susceptible animal models and/or higher exposure concentrations may be required to substantiate the results of the epidemiological studies. (Abstract does not represent USEPA policy. This research was supported in part by EPA CT826513.)