Direct and acute cardiotoxic effects of ultrafine air pollutants in spontaneously hypertensive rats (SHR) and Wistar‐Kyoto rats (WKY)

Abstract

We hypothesized that preexisting cardiovascular disease could affect the direct and acute cardiotoxic effects of ultrafine (UF) air pollutants. UF particles (UFP) isolated from 12.5 mg/L of standard particulate matter (National Institute of Standards and Technology) were studied in isolated Langendorff-perfused hearts obtained from SHR and WKY. Thirty min of perfusion with UFP reduced cardiac function in both groups - but to a greater extent in WKY. In SHR, developed pressure was reduced by 24 ± 4.4% of baseline and maximal dP/dT reduced by 20 ± 4.9%; in WKY, developed pressure was reduced by 44 ± 7.3% and maximal dP/dT by 42 ± 8.2% (p= 0.027 for maximal dP/dT in SHR vs. WKY). Coronary flow was decreased by 54% vs. 30% in the SHR vs. WKY (p< 0.05). Percent fluid content increased in both SHR and WKY exposed to UFP. The results of this study suggest that while UFP depresses myocardial contractile response and coronary flow in both SHR and WKY, that underlying hypertension does not necessarily worsen the response. Supported by US EPA Grant No. RD-83195201