Expectorant Effects of Immature Asian Pear Extract on PM2.5-Induced Subacute Pulmonary Injury in Mice

Abstract

This study investigated the expectorant effects of immature Asian pear extract (IAP; Pyrus pyrifolia Nakai) on subacute pulmonary injuries in Balb/c mice induced by particulate matter with a diameter of approximately 2.5 μm (PM2.5). IAP was administered at three doses, namely, 400, 200, and 100 mg/kg. The body weight and weight gain changes, lung weights, lung and body surface gross inspections, tracheal secretions, and substance P and ACh content in lung tissue homogenate were observed one day after the tenth IAP administration. The mRNA expression of the genes related to mucus production and lung histopathology was compared with that of the negative and positive controls. Favorable pulmonary protective effects on PM2.5-induced subacute pulmonary injuries, mucus overproduction, and respiratory acidosis were observed in groups treated with IAP at all three doses, possibly through potent anti-inflammatory and mucolytic expectorant activities mediated by the increase in the content of lung substances P and ACh and the downregulation of lung MUC5AC and MUC5B mRNA expression in a dose-dependent manner. The results of this study show that an appropriate oral administration of IAP has sufficient pulmonary protective effects and can be used as a candidate for the development of functional food ingredients.