Mosla chinensis Maxim extracts exert anti-inflammatory, antioxidant, and antifibrotic effects in silicosis

Mosla chinensis Maxim, a member of the Lamiaceae family, is widely distributed throughout southern Asia and is frequently used for its therapeutic benefits, particularly for respiratory disorders. However, studies specifically investigating its effects on pulmonary injury in vivo remain limited.

This study investigated the impact of Mosla chinensis Maxim water extract (MCWE) on a murine model of silicosis.

Silicosis was induced in mice through intratracheal instillation of silica particles, with this followed by daily oral administration of MCWE. Histopathological changes were assessed using Masson's trichrome staining and immunohistochemistry. Inflammatory cell counts and cytokine levels were measured in bronchoalveolar lavage fluid (BALF). Pulmonary fibroblasts and epithelial cells were used to determine the mechanistic effects of MCWE in vitro.

MCWE treatment attenuated silica-induced lung fibrosis in mice, effectively prevented immune cell infiltration, and reduced tumor necrosis factor-alpha and interleukin levels in BALF. MCWE also restored the activities of antioxidant enzymes and reduced oxidative stress. Silica-induced upregulation of transforming growth factor-beta (TGF-β) expression and small mothers against decapentaplegic (Smad) phosphorylation was reversed by MCWE. Furthermore, MCWE inhibited TGF-β-induced epithelial-mesenchymal transition in alveolar epithelial cells and prevented the differentiation of fibroblasts into myofibroblasts by interfering with TGF-β/Smad-dependent signaling. Rosmarinic acid was identified as the predominant compound in MCWE, and it can directly interfere with TGF-β binding to its receptor.

MCWE demonstrated antioxidant, anti-inflammatory, and antifibrotic effects in silicosis, supporting its potential as a lung-protective agent.