The effect of enriched versus depleted housing on eucalyptus smoke-induced cardiovascular dysfunction in mice

Abstract

Living conditions play a major role in health and well-being, particularly for the cardiovascular and pulmonary systems. Depleted housing contributes to impairment and development of disease, but how it impacts body resiliency during exposure to environmental stressors is unknown. This study examined the effect of depleted (DH) versus enriched housing (EH) on cardiopulmonary function and subsequent responses to wildfire smoke. Two cohorts of healthy female mice, one of them surgically implanted with radiotelemeters for the measurement of electrocardiogram, body temperature (Tco) and activity, were housed in either DH or EH for 7 weeks. Telemetered mice were exposed for 1 hour to filtered air (FA) and then flaming eucalyptus wildfire smoke (WS) while untelemetered mice, which were used for ventilatory assessment and tissue collection, were exposed to either FA or WS. Animals were continuously monitored for 5-7 days after exposure. EH prevented a decrease in Tco after radiotelemetry surgery. EH mice also had significantly higher activity levels and lower heart rate during and after FA and WS. Moreover, EH caused a decreased number of cardiac arrhythmias during WS. WS caused ventilatory depression in DH mice but not EH mice. Housing enrichment also upregulated the expression of cardioprotective genes in the heart. The results of this study indicate that housing conditions impact overall health and cardiopulmonary function. More importantly, depleted housing appears to worsen the response to air pollution. Thus, non-chemical factors should be considered when assessing the susceptibility of populations, especially when it comes to extreme environmental events.

Depleted housing elicits cardiopulmonary dysfunction after a single flaming eucalyptus wildfire smoke exposure in a sex-specific manner in ApoE knockout mice

“…We compared enriched housing, which includes several forms of environmental enrichment, with depleted housing to evaluate the role of non-chemical stressors like living conditions in modifying physiological resiliency to a single smoke exposure. Our previous work showed that enriched housing improves cardiovascular outcomes, speci cally a lower heart-rate, during and after a wild re smoke exposure and promotes an increase in the expression of cardioprotective genes in the left ventricle [27]. The current study expanded this approach to assess whether housing alters cardiovascular function in atherosclerotic-prone mice and whether the effects are sex-speci c. We found that the effect of housing on baseline cardiovascular function and the cardiovascular response to WS in ApoE (-/-) mice occurs in a sex-speci c manner.…”

“…However, few studies have focused on characterizing changes in cardiovascular physiology and function from housing enrichment and the ability of housing to modulate resiliency against an air pollution exposure. Our previous work showed that depleted housing causes increased heart rate, incidence of arrhythmias, and lower activity levels in healthy mice during a single smoke exposure [27]. However, the effect of this housing paradigm on underlying CVD and the corresponding response to WS remains unknown.…”