Exposure to fine particulate matter (PM2.5) can result in adverse cardiovascular responses including vascular endothelial dysfunction, whereas exercise training can promote cardiovascular health. However, whether exercise training can mitigate adverse vascular response to PM2.5 has been less studied. In the present study, we aimed to investigate the preventive effect of exercise training on vascular endothelial dysfunction induced by PM2.5 instillation. Six-week old male Wistar rats (n = 32) were divided into four groups (8 rats per group) by exercise status (sedentary vs. exercised) and PM2.5 exposure (instilled vs. non-instilled). Rats received treadmill training with moderate-intensity intervals in week 1 to 6, followed by three repeated PM2.5 instillation on every other day in week 7. Body weight and blood pressure were measured for each rat regularly during exercise training and before sacrifice. At sacrifice, thoracic aortas were isolated for functional response measurement to agonists. Nitric oxide bioavailability and high-density lipoprotein (HDL) function were also assessed. We observed that exercise training significantly reduced the body weight of rats, while PM2.5 instillation had little effect. Neither exercise training nor PM2.5 instillation had significant effects on blood pressure changes. However, exercise training effectively prevented endothelium-dependent vasorelaxation dysfunction and nitric oxide bioavailability reduction from subsequent PM2.5 instillation. In addition, exercise training promoted HDL function which were characterized as increased HDL cholesterol level, cholesterol efflux capacity, and reduced oxidization index; whereas PM2.5 instillation showed limited adverse impact on HDL function. Collectively, our results indicated that exercise training could promote HDL function and protect against endothelium dysfunction from PM2.5 instillation.
Keywords: Exercise; High-density lipoprotein; Instillation; Particulate matter; Vasorelaxation.
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