The effect of apigenin, an aryl hydrocarbon receptor antagonist, in Phthalate-Exacerbated eosinophilic asthma model

Endocrine disrupting chemicals have been known to contribute to the aggravation of inflammatory diseases including asthma. We aimed to investigate the effects of mono-n-butyl phthalate (MnBP) which is one of the representing phthalates, and its antagonist in an eosinophilic asthma mouse model. BALB/c mice were sensitized by intraperitoneal injection of ovalbumin (OVA) with alum and followed by three nebulized OVA challenges. MnBP was administered through drinking water administration throughout the study period, and its antagonist, apigenin, was orally treated for 14 days before OVA challenges. Mice were assessed for airway hyperresponsiveness (AHR), differential cell count and type 2 cytokines in bronchoalveolar lavage fluid were measured in vivo. The expression of the aryl hydrocarbon receptor was markedly increased when MnBP was administered. MnBP treatment increased AHR, airway inflammatory cells (including eosinophils), and type 2 cytokines following OVA challenge compared to vehicle-treated mice. However, apigenin treatment reduced all asthma features, such as AHR, airway inflammation, type 2 cytokines, and the expression of the aryl hydrocarbon receptor in MnBP-augmented eosinophilic asthma. Our study suggests that MnBP exposure may increase the risk of eosinophilic inflammation, and apigenin treatment may be a potential therapy for asthma exacerbated by endocrine-disrupting chemicals.