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A Novel Hypoxia Challenge Test Demonstrates Cardiovascular and Pulmonary Susceptibility to Acrolein Gas in Hypertensive Rats.
Citation:
Perez, C., A. D. Ledbetter, M. S. HAZARI, N. Haykal-Coates, A. P. Carll, D. W. WINSETT, D. P. Costa, AND A. FARRAJ. A Novel Hypoxia Challenge Test Demonstrates Cardiovascular and Pulmonary Susceptibility to Acrolein Gas in Hypertensive Rats. Presented at Society of Toxicology (SOT) Annual Meeting, San Francisco, CA, March 11 - September 15, 2012.
Impact/Purpose:
Preliminary assessments indicate that exposure to the environmental air pollutant acrolein modified the cardiopulmonary response to hypoxia challenge in hypertenisve, but not normal rats, suggesting that hypertension predisposes to the adverse health effects of air pollution exposure.
Description:
High levels of air pollution increase the risk of cardiovascular morbidity and mortality, especially in susceptible populations including those with hypertension. Stress tests are useful for manifesting latent effects of exposure, particularly at low concentrations, often when no overt effects are evident. The goal of this study was to develop a hypoxia stress test to illuminate susceptibility to environmental pollutants in a rodent model of hypertension. We hypothesized that acrolein exposure would increase sensitivity to hypoxia, particularly in hypertensive rats. Acrolein is an unsaturated aldehyde found in diesel exhaust and is a known environmental toxicant and potent pulmonary irritant. Spontaneously hypertensive (SH) and Wistar Kyoto (WKY; rats with normal blood pressure) rats, implanted with biopotential radiotelemetry transmitters were exposed once for 3 hours to 3 parts per million acrolein gas or filtered air (control) in whole body plethysmograph chambers and then challenged with a hypoxic environment (PO2 = 10% for 10 minutes) 24 hours later. Cardiovascular (ECG, HR, blood pressure) and ventilatory (breathing frequency, tidal volume, minute volume, inspiratory time, and expiratory time) parameters were monitored during both acrolein and hypoxia exposures. Hypoxia challenge caused a transient increase in heart rate, breathing frequency and minute volume while causing decreases in inspiratory and expiratory times in both exposure groups. Preliminary assessments, however, indicate that acrolein exposure modified the cardiopulmonary response to hypoxia challenge in SH, but not WKY rats, suggesting that hypertension predisposes to the adverse health effects of air pollution exposure. Blood pressure, ECG, and heart rate variability are currently being analyzed (This abstract does not reflect EPA policy).