Recent evidence suggests that Nigella sativa (NS) has an antiasthmatic (bronchodilatory) effect in the airways of asthmatic patients. Our objective was investigation of the hypothesis that NS supplementation reduces exercise-induced bronchoconstriction (EIB) in the maturing rat after highintensity interval training (HIIT). Forty male Wistar rats (aged 3 weeks) participated in this study. The animals after 2-week adaptation were divided into three groups: Base, control HIIT, and HIIT (HIITand NS group). HIIT group was performed on a treadmill (20 to 70 m/min, 30 min/day, 6 days/week). After 6 weeks HIIT, NS seed ethanol extract was fed by gavages to NS group 500 mg/kg for 3 weeks. Finally, animals were euthanized and their lung removed, weighted, and fixed in 10 % formalin. By routine and standard paraffin embedding, lung samples were sectioned in 5 μm and stained with H&E and studied histologically and histometrically. Massive inflammation and characteristics of lung remodeling including goblet cell hyperplasia, lymphocyte infiltration, and severe emphysema were observed in the lungs of HIIT-exposed rats. Administration of NS in the HIIT-exposed rats suppressed the inflammatory cell infiltration, goblet cell hyperplasia, and thickness tunica intima, tunica media, and tunica adventitia bronchi significantly. Administration of NS reduced the level of airway inflammation bronchi-induced asthma. The effect ofNS on EIB is probably mediated by the reduce thicknesses intima, media, and adventitia and the number of goblet cells of the bronchi. Our findings suggest that NS might have useful implications in the treatment and future research into EIB.
