Exposure of pregnant mice to an air pollutant aerosol increases asthma susceptibility in offspring.

Air pollution contributes to both exacerbation and development of bronchial asthma. Studies showed that coexposure to air pollution directly promotes sensitization to inhaled allergen in neonatal mice. The aim of this study was to investigate whether prenatal exposure to air pollution could also increase susceptibility to development of asthma in early life. Pregnant female BALB/c mice were exposed to aerosolized leachate of residual oil fly ash (ROFA, 50 mg/ml, 30 min) at 5, 3, and 1 d before delivery. Offspring were treated once at 3 d of age with ovalbumin (OVA, 5 μg) and alum (ip), an intentionally suboptimal dose for sensitization, exposed to aerosolized OVA (1%, 10 min) at 12–14 d or 32–35 d of age, and evaluated 2 d after the final exposure. The offspring of ROFA-exposed mothers (ROFA group) revealed increasing airway hyperresponsiveness (higher enhanced pause [Penh] to methacholine challenge) and elevated substantial numbers of eosinophils in the bronchoalveolar lavage flued (BALF). Histopathology...