2.3. Reagents and cell culture
HPLC grade solvents (acetonitrile and water) were purchased from Samchun Pure Chemicals (Pyeongtaek, Korea). Chicken egg ovalbumin (OVA), dinitrophenol (DNP)-specific monoclonal IgE, DNP-human serum albumin (HSA), and Evans blue were purchased from Sigma-Aldrich (St. Louis, MO, USA). Aluminum hydroxide (ImjectTM) were obtained from Thermo Fisher Scientific (Rockford, IL, USA). All other chemicals were obtained from Sigma-Aldrich unless otherwise noted. The human mast cell line HMC-1 was grown in Iscove´s Modified Dulbecco´s Medium (IMDM) supplemented with 10% fetal bovine serum (FBS) and 1% penicillin/streptomycin (Invitrogen, Carlsbad, CA, USA) at 37°C under humidified atmosphere containing 5% carbon dioxide (CO2).
2.4. OVA-induced allergic airway inflammation
BALB/c mice (6-8 week old) were used for experimental study after one week of acclimation. OVA-induced allergic airway inflammation was generated using previously described modifications (Casaro et al., 2019). Briefly, mice were sensitized by intraperitoneal injection on days 0 and 14 with 200 µL saline suspension containing 50 µg OVA emulsified in 1.6 mg aluminum hydroxide. After one week, mice were further challenged by intranasal inhalation of 1% OVA aerosol from days 21 to 24 for 30 min. Dimethyl sulfoxide (DMSO, 1%) in phosphate-buffered saline (PBS) or sophoricoside (3 or 30 mg/kg) was intraperitoneally administered an hour before OVA challenge from days 20 to 25. Mice were sacrificed 24 h after final treatment, and blood and organs were collected for further experiments. All animal care and studies were conducted under specific pathogen-free conditions in accordance with the guidelines of the Institutional Animal Care and Use Committee at Chung-Ang University (Approval number: 2019-00113).