Xiao-Qing-Long-Tang attenuates allergic airway inflammation and remodeling in repetitive Dermatogoides pteronyssinus challenged chronic asthmatic mice model

Ethnopharmacological relevance: Xiao-Qing-Long-Tang (XQLT) has been used for centuries in Asia to effectively treat patients with bronchial asthma. Aim of the study: We previously found that single and multiple doses of XQLT administered to sensitized mice before allergen challenge resulted in suppressed airway hyper-responsiveness and airway inflammation. In this study we aimed to investigate whether XQLT has the potential to attenuate the severity of asthma symptoms, and immunomodulatory mechanism of XQLT in a repetitive Dermatogoides pteronyssinus (D. pteronyssinus)-challenged chronic asthmatic mice model. Materials and methods: BALB/c mice were intratracheally (i.t.) inoculated with five doses of D. pteronyssinus (50 μl, 1 mg/ml) and orally administered of XQLT (1 g/kg) at 1-week intervals. At three days after the last challenge, mice were sacrificed to evaluate airway remodeling, inflammation, lung histological features, and the expression profiles of cytokines and various genes. Results: XQLT significantly reduced bronchial inflammatory cell infiltration and airway remodeling. It inhibited D. pteronyssinus-induced total IgE and D. pteronyssinus-specific IgG1 in serum, and changed the T _H2-bios in BALF by inhibiting the activation of NF-κB. Collagen assay and Histopathology indicated that XQLT reduced airway remodeling in the lung. Simultaneously, the RT-PCR analysis showed that XQLT downregulated IL-10, IL-13, RANTES, Eotaxin, and MCP-1 mRNA expression in the lung. Moreover, EMSA and immunohistochemistry staining demonstrated that XQLT inhibited NF-κB expression in the nucleus of bronchial epithelial cells. Conclusions: These results suggest that XQLT exhibits anti-airway inflammatory, anti-airway remodeling, and specific immunoregulatory effects in a chronic asthmatic mice model.