Effect of thymoquinone on proinflammatory cytokine release in lipopolysaccharide induced mononuclear cells

Lipopolysaccharides (LPS) can enter the systemic circulation through various infections, causing septic shock and death. In this study, it was aimed to investigate the effects of thymoquinone, the main component of Nigella sativa (Nigella sativa) seeds, on proinflammatory cytokine expression in LPS-induced blood mononuclear cells (MNC). MNCs were isolated from blood samples of 10 healthy donors by concentration-gradient centrifugation method. Cells were exposed to LPS for three hours. Groups containing 100 ng/ml LPS, 10-100 µM thymoquinone, 1 µM dexamethasone and their combinations were formed and IL-1β, TNF-α, IFγ and IL10 mRNA expressions were analyzed using RT-qPCR and ELISA method. Thymoquinone caused remarkable reduction in TNFα, IFγ and IL-1β mRNA expressions in all cell groups. The mRNA expressions of IL-10, an anti-inflammatory cytokine, were increased in LPS-induced groups. In contrast, changes in protein expressions were not significant after short-term exposure. This study indicates that thymoquinone can suppress mRNA expression of proinflammatory cytokines and may have anti-inflammatory effects on IL-10. However, effects on cytokine expression need to be confirmed in long-term exposure and in vivo models. Our study shows the potential for thymoquinone to be an anti-inflammatory agent in sepsis and possibly other inflammation conditions where proinflammatory cytokines are active.