Sojadodamgangki-tang Attenuates Allergic Lung Inflammation by Inhibiting T helper 2 cells and Augmenting Alveolar Macrophages

Ethnopharmacological relevance: Sojadodamgangki-tang (SDG) is a traditional East-Asian herbal medicine mainly composed of Pinellia ternate (Thunb.) Makino, Perilla frutescens (L.) Britt and 10 kinds of medicinal herbs. It has been used to treat asthma and mucus secretion including lung and bronchi.

Aim of the study: The aim of this study was to investigate the anti-inflammatory effects of Sojadodamgangki-tang (SDG) on allergic lung inflammation in vitro and in vivo as well as the underlying mechanisms.

Materials and methods: We used an ovalbumin (OVA)-induced murine allergic airway inflammation model. Five groups of 8-week-old female BALB/C mice were divided into the following groups: saline control group, the vehicle (allergic) group that received OVA only, groups that received OVA and SDG (200 mg/kg or 400 mg/kg), and a positive control group that received OVA and Dexamethasone (5 mg/kg). In vitro experiments include T helper 2 (TH2) polarization system, murine macrophage cell culture, and human bronchial epithelial cell line (BEAS-2B) culture.

Results: SDG administration reduced allergic airway inflammatory cell infiltration, especially of eosinophils, mucus production, Th2 cell activation, OVA-specific immunoglobulin E (IgE), and total IgE production. Moreover, the activation of alveolar macrophages, which leads to immune tolerance in the steady state, was promoted by SDG treatment. Interestingly, SDG treatment also reduced the production of alarmin cytokines by the human bronchial epithelial cell line BEAS-2B stimulated with urban particulate matter.

Conclusion: Our findings indicate that SDG has potential as a therapeutic drug to inhibit Th2 cell activation and promote alveolar macrophage activation.

Keywords: Alarmin; Allergic lung inflammation; Alveolar macrophage; Bronchoalveolar lavage fluid; Particulate matter; Sojadodamgangki-tang; Th2 cells activation.