The effect of single dose of thymoquinone, the main constituents of Nigella sativa, in guinea pig model of asthma

INTRODUCTION In previous studies, the relaxant and antihistaminic effects of thymoquinone, the main constituents of Nigella sativa, have been demonstrated on guinea pig tracheal chains. In the present study, the prophylactic effect of (IP) single dose of thymoquinone on tracheal responsiveness and lung inflammation of guinea pig model of asthma was examined. METHODS Thirty guinea pigs were randomly divided to 3 groups; control (C), sensitized (S) and pretreated group with (TQ); 3 mg/kg, IP (S+TQ). Tracheal responsiveness to methacholine and ovalbumin (OA), total and differential cell count in bronchoalveolar lavage, lung pathological changes and blood Interleukin 4(IL-4) and Interferon gamma (IFNγ) level in three groups were measured. RESULTS Increased tracheal responsiveness to methacholine and OA, lung lavage fluid white blood cell (WBC) and eosinophil count, IL-4 and IFN-γ levels and pathological changes were seen in sensitized group in comparison to control group (p<0.001 to p<0.05). Decreased tracheal responsiveness to methacholine and OA, pathological changes and bronchoalveolar lavage eosinophil were observed in S+TQ group compared to S group (p<0.001 to p<0.05). However, tracheal responsiveness to methacholine and OA, contractility, bronchoalveolar lavage WBC and eosinophil and most of pathological changes in S+TQ group were significantly higher than those in controls (p<0.01 to p<0.05). CONCLUSION These results showed the preventive effect of single dose of thymoquinone on guinea pig model of asthma.