The anti-inflammatory effects of thymoquinone in a rat model of allergic rhinitis

Abstract

Objectives: This study aims to investigate the effect of thymoquinone TQ on airway inflammation in a rat model of allergic rhinitis AR . Materials and Methods: Allergic rhinitis was induced in 42 rats by intraperitoneal sensitization and intranasal challenge with ovalbumin OVA . The animals were divided into six subgroups n=7/per cage : healthy controls, AR group, AR group treated with corticosteroid dexamethasone 1 mg/kg; CS+AR , healthy rats that were given only TQ of 10 mg/kg TQ10 , AR group treated with TQ of 3 mg/kg TQ3+AR and AR group treated with TQ of 10 mg/kg TQ10+AR . We measured the serum levels of interferon-gamma IFN-g , interleukin-4 IL-4 , IL-10, and OVA-specific immunoglobulin E Ig-E . Histopathologic changes in nasal mucosa and expression of tumor necrosis factor-alpha TNF-a and IL-1b were evaluated. Results: Thymoquinone has inhibited the production of the IL-4, OVA-specific IgE, and the expression of TNF-a and IL-1b. It also reduced eosinophil infiltration and edema in the nasal mucosa while it has no increased effect on IFN-g and IL-10. Conclusion: We observed that TQ has multiple suppressive effects on allergic response. Thymoquinone may be considered as a supplemental agent in the treatment of allergic rhinitis.