Ambient air particulate matter enhances airway hyperresponsiveness and airway inflammation in murine model of asthma

Abstract

Patients with asthma are likely to experience acute exacerbation by exposure to particulate matter (PM), which is a complex mixture of small particles and liquid droplets suspended in the air. The mechanism for aggravation of asthma by exposure to PM is poorly determined yet. We collected PM using high-volume air sampler in Incheon, Korea and suspended it in PBS. Murine model of asthma was induced in BALB/c mice by intraperitoneal injection of ovalubmin (OVA) and alum, and intranasal administration of OVA. During challenge period, mice were exposed to PM and evaluated for change in airway hyperresponsiveness (AHR) and inflammation compared to unexposed mice. Exposure to PM in OVA-sensitized and challenged mice showed significant increase in AHR accompanied by increase in inflammatory cell count in BAL fluid or histology, compared to PM-unexposed mice with asthma. These findings suggest PM plays an important role in aggravation of asthma by enhancing both AHR and airway inflammation.