Effect of Pre‐exercise and PM2.5 on Lung Pulmonary Function and Inflammation in Aged Rats

Abstract

PURPOSEExposure of particulate matter of less than 2.5 μm (PM2.5) has been associated with adverse respiratory and the risk of inflammation. While regular physical activity (PA) reduces the risk of many adverse health effects. This study aimed to examine the protection of pre‐exercise on adverse health effects of Pulmonary Function and inflammatory induced by PM2.5 exposures in aged rats.METHODS24 male wistar rats, aged 16 months, were randomly divided into 4 groups: Sedentary (S), Exercise (E), Sedentary+PM2.5 exposures (S+PM), and Exercise+ PM2.5 exposures (E+PM).The rats in all E‐related groups went through an 8‐week aerobic treadmill exercise protocol (65–75%VO2max, 30 min) at every other day. The PM‐related groups of aged rats were exposed to concentrated PM2.5 in Beijing(7 days/week, 4 hours/day). After 2‐week PM Exposure, the pulmonary function examined by whole body plethysmography, structure of lung tissues were observed by HE staining, and the counts of leukocyte, sIgA, CRP and TNF‐α concentration were examined.RESULTS1)Compared with S group, following changes occurred in S+PM group after 2‐week PM2.5 exposure: lung tissues were seriously damaged, local bleeding, pus exudation, and inflammatory cell infiltration, as well as the decline of sIgA level (↓45%, ES=0.87, p<0.05) and percentage of neutrophil (↓62%, ES=0.45,p<0.05), while the incline of the Index of constriction (↑76%,ES=3.97, p<0.05), the rejection index, CRP(↑24%, ES=0.83, p<0.05), and TNF‐α(↑38%, ES=0.84, p<0.05) were observed. 2) Compared with S+PM group, the structure of lung tissues and pulmonary function were obviously improved in E+PM group. In addition, the sIgA concentration (↑85%, ES=0.70, p<0.05) were enhanced markedly, while CRP (↑21%, ES=0.76, p<0.05), and TNF‐α level (↑25%, ES=0.74, p<0.05) were decreased in E+PM group compared with S+PM group.CONCLUSION2‐week PM2.5 exposures led to an increased susceptibility of infections, index of constriction and susceptibility of pulmonary function in aged rats. Moderate pre‐exercise has beneficial effects on pulmonary function and reducing the susceptibility to inflammation.Support or Funding Informationthe National Natural Science Foundation of China (11775059 and 31900845), the China Postdoctoral Science Foundation (2018T110076), and the Fundamental Research Foundation of the China Institute of Sport Science (18‐02, 19–22, and 19–34).Effect of Pre‐exercise and PM2.5 on Pulmonary Functions in Aged Rats.*P<.05. All values were presented as Mean ± SD, n= 10 for each group.Figure 1Impact of PM2.5 Exposures and Pre‐exercise on Inflammation in Aged Rats.*P<.05. All values were presented as Mean ± SD, n= 10 for each group.Figure 2