Moderate-intensity physical activity reduces systemic inflammation and maintains cardiorespiratory function following chronic particulate matter2.5 exposure in rats

Alannah Van Waveren,Mitch J Duncan,Fiona Coulson,Andrew Fenning

doi:10.1016/j.toxrep.2019.12.004

Alannah Van Waveren, Mitch J Duncan + Show 2 more

Open Access

https://doi.org/10.1016/j.toxrep.2019.12.004

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Abstract

AimsThe purpose of the current study is to 1) examine the beneficial effects of moderate levels of physical activity (PA) on functional and biochemical markers of the cardiorespiratory system, 2) establish the detrimental effects of a single, daily particulate matter (PM) exposure event on cardiorespiratory function and 3) determine if exercising during daily PM exposure increases the deleterious effects caused by PM exposure due to increased inhalation of particulates on cardiorespiratory function. MethodsFour groups of 16 rats were used: control (CON), PA, PM2.5 exposed and PA combined with PM2.5 exposure (PA + PM). Animals were purchased at 4 weeks old. However, both PA and PM exposure was initiated when the animals reached 8 weeks of age, for 8 weeks. ResultsPA alone did not alter body weight or blood pressure (BP) compared to control animals. However, there was a significant decrease in epididymal fat pad mass in the PA group. The PM exposed rats were hypertensive, showed increased systemic inflammation and oxidative stress, and had decreased spleen mass without pathological changes in the cardiac action potential or impaired vascular function. PA was able to decrease systemic inflammation in PM exposed animals, including a reduction in IL-6 serum levels, however, this did not translate to an improvement in BP or vascular reactivity. Smooth muscle relaxation in the trachea from the combination PA + PM group was not significantly different to CON and PA groups but was significantly higher than the PM group. ConclusionsThe current study showed that while there is an increased cardiovascular disease (CVD) risk associated with PM exposure, engaging in PA during exposure events imposes no increased risk with exercise providing a protective mechanism against some of the biochemical signaling changes caused by inhaled PM.

Highlights

A physically inactive lifestyle has been shown to be detrimental to long-term health as evidenced by the associated increased risk of obesity and many chronic diseases including cardiovascular disease (CVD), metabolic syndrome and diabetes [1,2,3]
There were no significant changes noted in body mass, organ mass or in the Physical activity (PA) group compared to the CON and Particulate matter (PM) groups (Table 1)
In the physical activity (PA and PA + PM) rats there was a significant increase (P < 0.05) in lipid peroxidation, a significant decrease (P < 0.05) in serum IL-6 concentrations was observed compared to both the CON and PM groups (Table 1)

Summary

Introduction

A physically inactive lifestyle has been shown to be detrimental to long-term health as evidenced by the associated increased risk of obesity and many chronic diseases including cardiovascular disease (CVD), metabolic syndrome and diabetes [1,2,3]. Physical activity (PA) is associated with improved metabolic function and reduced systemic inflammation [4]. Weight-loss that is often associated with PA has been shown to have many health benefits including improvement of endothelial dysfunction and decreased systemic inflammation [5]. Marathon runners have been found to have increased TNF-α, IL-6 and IL-1β following a race [10,11] This makes duration and intensity an important consideration when considering physical activity to reduce risk of CVD development or treatment

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