Dietary New Zealand propolis supplementation reduced proinflammatory cytokines in an acute mouse model of air pollution exposure, without impacting on immune cell infiltration or lung function

Abstract

• Propolis reduced urban dust-induced lung TNFα, IL-4, and IL-6 production in mice. • Propolis did not alter urban dust-induced immune cell infiltration into mice lungs. • Propolis did not alter urban dust-induced airways constriction in mice. • This suggests that Propolis only partially reduces inflammatory responses in an urban dust mouse model. Air pollution is estimated to cause 7 million annual deaths globally. Our aim was to determine if dietary propolis consumption could prevent the immune and functional damage in a mouse model of acute urban dust exposure. Female C57BL/6J mice were challenged three times with intranasal urban dust over seven days which significantly increased proinflammatory cytokines and immune cells in the lung 24 h post final challenge. Dietary New Zealand propolis (2%) with gamma cyclodextrin supplementation reduced urban dust-induced lung TNFα, IL-4, and IL-6 cytokine production; but did not alter immune cell infiltration into the lung, or lung function outcomes. This suggests that daily consumption of 8% propolis with gamma cyclodextrin supplemented food was sufficient to reduce urban dust pollution-induced proinflammatory cytokine production but was not sufficient to prevent immune cell recruitment into the lung or lung function decline in a murine model of lung inflammation.