Differential effects of intense exercise and pollution on the airways in a murine model

Abstract

Background Exercise-induced bronchoconstriction (EIB) is a transient airway narrowing, occurring during or shortly after intensive exercise. It is highly prevalent in non-asthmatic outdoor endurance athletes suggesting an important contribution of air pollution in the development of EIB. Therefore, more research is necessary to investigate the combination of exercise and pollutants on the airways. Methods Balbc/ByJ mice were intranasally challenged 5 days a week for 3 weeks with saline or 0.2 mg/ml diesel exhaust particles (DEP), prior to a daily incremental running session or non-exercise session. Once a week, the early ventilatory response was measured and lung function was determined at day 24. Airway inflammation and cytokine levels were evaluated in bronchoalveolar lavage fluid. Furthermore, innate lymphoid cells, dendritic cells and tight junction mRNA expression were determined in lung tissue. Results Submaximal exercise resulted in acute alterations of the breathing pattern and significantly improved FEV0.1 at day 24. DEP exposure induced neutrophilic airway inflammation, accompanied with increased percentages of CD11b+ DC in lung tissue and pro-inflammatory cytokines, such as IL-13, MCP-1, GM-CSF and KC. Occludin and claudin-1(Cldn-1) expression were respectively increased and decreased by DEP exposure. Whereas, exercise increased Cldn-3 and Cldn-18 expression. Combining exercise and DEP exposure resulted in significantly increased SP-D levels in the airways. Conclusion DEP exposure induced typical airway neutrophilia, DC recruitment and pro-inflammatory cytokine production. Whereas, intensive exercise induced changes of the breathing pattern. The combination of both triggers resulted in a dysregulation of tight junction expression, suggesting that intensive exercise in polluted environments can induce important changes in the airway physiology and integrity.

Chlorine exposure and intensive exercise induces airway hyperreactivity in a 3-week murine exercise model

“…In addition, in a model for exercise-induced bronchoconstriction with a running protocol of 3 to 5 weeks, no airway inflammation was present, but airway hyperreactivity was induced probably via the synthesis of cysteinyl-leukotrienes by the airway epithelium (Ueno et al, 2020). This was confirmed by previous work in our group, where in a murine 3-week running model airway hyperreactivity was observed, but no inflammation (Decaesteker et al, 2021). Airway permeability and epithelial integrity was evaluated as chlorine is an irritant and irritants can have a negative effect on airway epithelial barrier (Van Den Broucke et al, 2018).…”

Differential pulmonary toxicity and autoantibody formation in genetically distinct mouse strains following combined exposure to silica and diesel exhaust particles

“…Lung function was assessed using the FlexiVent FX system (SCIREQ, EMKA Technologies, Montreal, Canada), and mice were subsequently euthanized. Measurements were performed as described by Devos et al [ 63 , 64 ]. Briefly, the system was designed to measure both forced oscillations (QP3 perturbation) and forced expiration parameters and was operated with FlexiWare™ 7.6 software.…”

Emerging concern on air pollution and health: Trade-off between air pollution exposure and physical activity

“…Thus, animal models have become indispensable for studying the health effects and mechanisms of air pollution and physical activity. The study found that physical activity in a polluted environment altered airway permeability [ 50 , 51 ] and suppressed particulate-matter-induced lung inflammation and systemic inflammation in mouse models [ 52 , 53 ]. Moreover, some studies have observed that exercise can protect mice from PM 2.5 -induced cardiovascular damage [ 54 ] and improve heart rate variability [ 55 ].…”