Ultrafine particulate matter exposure impairs vasorelaxant response in superoxide dismutase 2-deficient murine aortic rings

ABSTRACTStudies have linked exposure to ultrafine particulate matter (PM) and adverse cardiovascular events. PM-induced oxidative stress is believed to be a key mechanism underlying observed adverse vascular effects. Advanced age is one factor known to decrease antioxidant defenses and confer susceptibility to the detrimental vascular effects seen following PM exposure. The present study was designed to investigate the vasomotor responses following ultrafine PM exposure in wild type (WT) and superoxide dismutase 2-deficient (SOD2+/–) mice that possess decreased antioxidant defense. Thoracic aortic rings isolated from young and aged WT and SOD2+/– mice were exposed to ultrafine PM in a tissue bath system. Aortic rings were then constricted with increasing concentrations of phenylephrine, followed by relaxation with rising amounts of nitroglycerin (NTG). Data demonstrated that ultrafine PM decreased the relaxation response in both young WT and young SOD2+/– mouse aortas, and relaxation was significantly red...