Age differences in the pulmonary and vascular pathophysiologic processes after long-term real-time exposure to particulate matter in rats.

Existing experimental data do not sufficiently explain which pathophysiologic processes are involved in different age of rats exposed to long-term particulate matter. This study explored the pulmonary and cardiovascular effects of long-term PM2.5 and PM10 exposure in juvenile, adult and senescent rats. Tail cuff plethysmography, whole-body plethysmographic system, myograph, enzyme-linked immunosorbent assay, and inductively coupled plasma-mass spectrometry were used to detect the blood pressure, lung function, endothelium-dependent relaxation, inflammatory cytokines and heavy metals, respectively. The exposure time was from November, 2017 to October, 2018, and the average concentrations of PM2.5 and PM10 were 78.7 and 128.2 μg/m3, respectively. Compared with the filtered air group, the body weight and survival rate in PM2.5 and PM10 exposure group were significantly decreased, and the survival rate of senescent exposed rats was only 30%. PM2.5 and PM10 exposure increased the blood pressure, elevated the levels of serum and bronchoalveolar lavage fluid inflammatory factors, and the senescent exposed rats showed an earlier rising trend in blood pressure and inflammatory factors than those of juvenile and adult exposed rats. Long-term PM2.5 and PM10 exposure could destroy intrapulmonary and small resistance arteries endothelial function, causing vasodilation disorders. PM2.5 and PM10 exposure caused particulate matter to accumulate in the lungs. Additionally, PM2.5 and PM10 exposure could also cause accumulation of cadmium (Cd) and lead in the liver, and chromium and Cd in the kidney. In conclusion, ambient PM2.5 and PM10 exposure induced particulate matter to accumulate in the body, caused severe pulmonary and vascular disorders, and demonstrated age-associated differences.