Background: Nigella sativa (NS) is a traditionally used herb for treatment of asthma by different publics . However, there are few studies on its efficacy and mechanisms of action.
Objective: To investigate the effects of NS fixed oil -compared to dexamethasone (Dex)- on iNOS, peripheral blood eosinophils (PBE), serum IgG1 and airway inflammation in murine model of allergic asthma.
Methods: mice were divided into 4 groups:
G1: six naïve control mice. G2: ten mice were sensitized intraperitoneally and challenged intratracheally with conalbumin . G3: six mice were sensitized, challenged and treated with Dex for 17 days. G4: nine mice were sensitized, challenged and treated with NS fixed oil for 17 days.
Histopathology and immunohistochemical study of iNOS in lung tissues, detection of PBE % and serum IgG1were done.
Results: Lung tissue iNOS expression increased non significantly in G2 compared with G1(p 0.14). NS fixed oil significantly reduced PBE%, IgG1 and lung inflammation, while non significantly reduced iNOS expression, compared with G2 (p 0.035, 0.001, 0.03, 0.06 respectively) . These effects were comparable to the effects of Dex.
Conclusion: iNOS has a limited - if any – role in allergic airway inflammation. Other isoenzymes (constitutive) may be responsible for the production of NO present in asthma. NS exhibited airway anti-inflammatory and immunomodulatory effects on PBE and serum IgG1 which may be useful for the treatment of asthma.