Effect of thymoquinone on the lung pathology and cytokine levels of ovalbumin-sensitized guinea pigs.

Different pharmacological effects from Nigella sativa have been demonstrated in guinea pig tracheal chains in previous studies. In the present study, the prophylactic effects of thymoquinone on lung pathology as well as blood IL-4 and IFN-γ levels in sensitized guinea pigs were examined. Three groups of guinea pigs sensitized to ovalbumin were given drinking water alone (group S) or drinking water containing low (LTQ) or high (HTQ) concentrations of thymoquinone (groups S + LTQ and S + HTQ). The lung pathology as well as blood IL-4 and IFN-γ levels of the sensitized and the control guinea pigs were evaluated in three sensitized and one control group (n = 8, for all groups). The lungs of the S group showed significant pathological changes (p < 0.001). Blood IL-4 and IFN-γ levels were increased in the sensitized animals compared to those of controls (p < 0.01 and p < 0.001, respectively). Treatment of the S animals with thymoquinone significantly improved their pathological changes to the lung and decreased their IL-4 levels (p < 0.05 to p < 0.001) but increased their IFN-γ levels (p < 0.001). These results showed a preventive effect of thymoquinone on lung inflammation in sensitized guinea pigs.