Ambient Particulate Matter Affects Cardiac Recovery in a Langendorff Ischemia Model

Exposure to ambient particulate matter (PM) is associated with increased mortality and morbidity among subjects with cardiovascular impairment. We hypothesized that exposure of spontaneously hypertensive (SH) rats to PM impairs the recovery of cardiovascular performance after coronary occlusion and reperfusion-ischemia. SH rats were exposed by intratracheal instillation to saline, standard urban PM (Ottawa dust EHC-93, 10 mg/kg body weight) or endotoxin (lipopolysaccharides LPS, 350 EU/animal) to induce a similar pulmonary inflammation. At 4 h postexposure, hearts were isolated and retrograde perfused in a Langendorff model. The experimental protocol included 35 min of coronary occlusion followed by 120 min of reperfusion, during which left ventricular developing pressure (LDVP), coronary flow (CF), and heart rate (HR) were measured. Baseline LVDP in particle-instilled SH rats was significantly decreased compared to saline-instilled animals. In addition, after ischemia the recovery of LDVP was much slower...