Particulate matter (PM) is a complex mixture of airborne solid particles and liquid droplets originating from various environmental sources, and it has been implicated in the initiation, development, and progression of pulmonary inflammation and respiratory diseases. However, the underlying associated molecular mechanisms remain unclear. Adenophora divaricate Franch. & Sav. (AD) is a medicinal herb classified within the Campanulaceae family and genus Adenophora, with a broad geographic distribution across East Asia, including Korea, Asia, and Russia. In this study, we investigated the mechanisms underlying the effects of AD on PM-induced lung inflammation in both PM-stimulated RAW264.7 cells and PM-exposed mice. Considering that the reactive oxygen species (ROS)-mediated thioredoxin-interacting protein (TXNIP) and NOD-like receptor pyrin domain containing (NLRP3) inflammasome pathway plays a role in PM-induced inflammatory responses, we focused on determining whether AD exerts its anti-inflammatory effects through modulation of this signaling pathway. The anti-inflammatory properties of the methanolic extract of AD were evaluated using PM-stimulated RAW264.7 cells and PM-exposed mice. PM was administered intranasally to mice for 7 days, whereas AD or dexamethasone was orally administered for the same duration. AD treatment significantly attenuated pulmonary inflammation, as evidenced by reduced inflammatory cell counts and decreased cytokine levels in bronchoalveolar lavage fluid. In addition, AD decreased oxidative stress marker (ROS and thiobarbituric acid reactive substances) while increasing glutathione content, leading to suppression of TXNIP/NLRP3 inflammasome expression. Histopathological analysis revealed a marked alleviation of inflammatory responses in lung tissue, characterized by diminished inflammatory cell infiltration and reduced alveolar wall thickening. Collectively, these findings suggest ROS-mediated TXNIP serves as a key regulatory factor, and AD may serve as a potential therapeutic agent for pulmonary inflammation.
Ha et al. (Thu,) studied this question.