Background: High ambient levels of ozone (O3) and fine particulate matter (PM2.5) are associated with cardiovascular morbidity and mortality, especially in people with preexisting cardiopulmonary diseases. Enhanced susceptibility to the toxicity of air pollutants may include individuals with metabolic syndrome (MetS).
Objective: We tested the hypothesis that cardiovascular responses to O3 and PM2.5 will be enhanced in rats with diet-induced MetS.
Methods: Male Sprague-Dawley rats were fed a high-fructose diet (HFrD) to induce MetS and then exposed to O3, concentrated ambient PM2.5, or the combination of O3 plus PM2.5 for 9 days. Data related to heart rate (HR), HR variability (HRV), and blood pressure (BP) were collected.
Results: Consistent with MetS, HFrD rats were hypertensive and insulin resistant, and had elevated fasting levels of blood glucose and triglycerides. Decreases in HR and BP, which were found in all exposure groups, were greater and more persistent in HFrD rats compared with those fed a normal diet (ND). Coexposure to O3 plus PM2.5 induced acute drops in HR and BP in all rats, but only ND rats adapted after 2 days. HFrD rats had little exposure-related changes in HRV, whereas ND rats had increased HRV during O3 exposure, modest decreases with PM2.5, and dramatic decreases during O3 plus PM2.5 coexposures.
Conclusions: Cardiovascular depression in O3– and PM2.5-exposed rats was enhanced and prolonged in rats with HFrD-induced MetS. These results in rodents suggest that people with MetS may be prone to similar exaggerated BP and HR responses to inhaled air pollutants.
1Department of Pathobiology and Diagnostic Investigation, and 2Center for Integrative Toxicology, Michigan State University, East Lansing, Michigan, USA; 3Department of Biostatistics, and 4Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, Michigan, USA; 5Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan, USA; 6Davis Heart and Lung Research Institute, The Ohio State University College of Medicine, Columbus, Ohio, USA; 7Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
Recommended Citation:
James G. Wagner,1,2 Katryn Allen,et al. Cardiovascular Depression in Rats Exposed to Inhaled Particulate Matter and Ozone: Effects of Diet-Induced Metabolic Syndrome[J]. Environmental Health Perspectives,2014-01-01,Volume 122(Issue 1):27