Mast cells are key mediators in the pulmonary inflammatory response to formaldehyde exposure.

Formaldehyde (FA) is a common chemical linked to respiratory problems such as airway hyperresponsiveness and pulmonary inflammation. Due to its toxicological effects and ease of mass production, FA is also recognized as a significant chemical threat by the U.S. Department of Homeland Security. This study investigates the role of mast cells in the pulmonary inflammatory response to acute high-dose FA exposure. Using wild-type (C57BL/6J) and mast cell-deficient (KitW-sh) mouse models, we assessed the impact of oropharyngeal aspiration of FA on lung pathology. Our findings reveal that C57BL/6J mice experienced significant increases in cellular infiltration, altered immune cell populations, and changes in lipid mediator profiles. In contrast, KitW-sh mice exhibited significantly reduced inflammatory responses. Notably, the presence of mast cells was associated with enhanced dendritic cell migration and differential production of bioactive lipid mediators, such as specialized pro-resolving mediators and pro-inflammatory leukotrienes in C57BL/6J mice. These results highlight the crucial role of mast cells in the immune response to FA and suggest they could be therapeutic targets for treating FA-induced lung inflammation.