Immunomodulatory effects of modified Liu-Wei-Di-Huang-Wan Traditional Chinese medicine on allergic asthmatic mice

Allergic asthma occurs worldwide and is particularly prevalent in westernized countries characterized by chronic airway inflammation resulting in airway hyperresponsiveness. The house dust mites (HDM) including Dermatophagoides pteronyssinus are major sources of sensitization and triggering allergic symptoms in asthmatic patients. The Der p 2 is a major allergen and the predominant source of causative respiratory disorders which induce airway inflammation and bronchial constriction in mite-allergic patients. Few studies evaluate the ameliorating effects of modified Liu-Wei-Di-Huang-Wan (modified LWDHW) on allergic asthma.

This study aimed to investigate the immunological mechanisms of modified LWDHW on the reductions of airway inflammation, signal transduction, inflammatory cytokine production, Th2 cell proliferation, and bronchial obstruction in Der p 2-induced asthmatic mice.

At least ten active ingredients were contained in the formula of modified LWDHW- 1217A and 1217B. Results showed that the immunoglobulin generations (Der p 2 specific- IgE and IgG1), inflammatory cytokine productions (IL-5 and IL-13) in the Sera and BALF could be down-regulated, and the Th1-cytokine productions (IL-12 and IFN-γ) be increased after immunotherapy with modified LWDHW of 1217A or 1217B. The inflammatory cell infiltrations (macrophages, eosinophils, and neutrophils) in the airway and the expressions of T_H2-related genes (IL-4, IL-5, and IL-13), T_H2-related transcription factor (GATA-3), and neutrophil chemotactic chemokine (IL-8) in the lung tissue of asthmatic mice were significantly decreased after the immunotherapy. The Th1/Th2 polarization had been identified that the IL-4⁺/CD4⁺ T cells were downregulated and IFN-γ⁺/CD4⁺ T cells were increased. The airway hyperresponsiveness to methacholine inhalation of Penh values was significantly decreased in the treated groups. There were significant improvements in the bronchus histopathology after immunotherapy with 1217A or 1217B which were evaluated by tracheal thickness, inflammatory cell count, and tracheal rupture of mouse lung.

It revealed that 1217A or 1217B could regulate the immune responses and improve pulmonary function. Data suggests that modified LWDHW of 1217A or 1217B have the potential for use as a therapeutic intervention for the treatment of mite allergen Der p 2-induced allergic asthma.