Saikosaponin D inhibits nasal inflammation by regulating the transcription factors T-box protein expressed in T cells/GATA-3 and retinoic acid-related orphan nuclear receptor γt in a murine model of allergic rhinitis.

CONTEXT: Saikosaponin D (SSD) is a commonly prescribed agent against inflammatory diseases in Asian countries. However, the anti-allergic inflammatory effect of SSD in allergic rhinitis (AR) model is not well known.

OBJECTIVE: We investigated the anti-allergic and anti-inflammatory effects of SSD on the ovalbumin (OVA)-induced AR model.

MATERIALS AND METHOD: BALB/c mice were divided into the control, OVA, OVA + SSD, and OVA + dexamethasone (Dex) groups. AR was established by intraperitoneal injection with OVA adsorbed to aluminum hydroxide, and intranasal challenge with OVA. Thereafter, the mice were treated with 10 mg/kg BW (Body weight) of OVA + SSD and 2.5 mg/kg BW of Dex orally for 11 days before being challenged. Subsequently, the mice were challenged with OVA 1 h after SSD or Dex treatment. The Control group was treated with saline only.

RESULTS: The addition of 10 mg/kg BW of OVA + SSD significantly ameliorated the nasal symptoms including sneezing and rubbing from 30 ± 5.2 times in OVA group to 20 ± 5.8 times. Moreover, OVA + SSD group decreased the production of TNF-α, IL-4, IL-5, IL-17, GATA-3 and RORγ about 1.2-1.4-fold compared to the OVA-induced AR mice near to 2.5 mg/kg BW of Dex levels. Meanwhile OVA + SSD group slightly increased the levels of INF-γ, IL-12 and T-bet about 1.8-2.0-fold compared to the OVA group near to control group. Notably, OVA + SSD group also reduced the levels of OVA-specific IgE and IgG1 about 0.5-2.5-fold compared OVA group but increased the levels of IgG2a in serum. The results were analyzed using Graph Pad Prism software (v5.0, La Jolla, CA, USA).

CONCLUSION: SSD may represent an alternative therapeutic approach for the treatment of patients with AR through the regulation of transcription factors T-bet, GATA-3, and RORγ in inflammatory cells.