Three different concentrations of Nigella sativa (N. sativa) ethanolic extract, thymoquinone (TQ), dexamethasone, and saline were examined to see whether they had any effects on cell viability, proliferation, and interleukin 4 (IL-4) and interferon-γ (IFN-γ) secretion in non-stimulated, phytohemagglutinin (PHA) and concavaline A (Con A)-stimulated splenocytes. In PHA and Con A-stimulated splenocytes, cell viability and proliferation were increased and Con A shifted cytokine profile towards Th2 balance. Dexamethasone treatment showed a suppression in viability, IFNγ and IL-4 secretion in non-stimulated and stimulated splenocytes. Extract and TQ reduced the viability and inhibited the proliferation of stimulated and non-stimulated splenocytes concentration-dependently. Higher concentrations of N. sativa (1000 mg/ml) and TQ (5 and 10 mg/ml) reduced the secretion of IL-4 in stimulated cells. Two higher concentrations of N. sativa had decreased IFNγ secretion in both stimulated and non-stimulated cells. In non-stimulated cells, only the highest and in Con A-stimulated cells, all TQ concentrations had inhibited IFNγ secretion. The highest concentration of N. sativa increased IFNγ/IL-4 ratio in both stimulated and non-stimulated cells while higher concentrations of TQ only had the same effect on stimulated cells. N. sativa and TQ showed cytotoxic inhibitory effect on rat splenocytes and on Th1/Th2 cytokines concentration-dependently. Higher concentrations of extract and TQ increased cytokines balance in Th1/Th2.
Keywords: Nigella sativa; Splenocytes; Th1/Th2 balance; Thymoquinone.
Copyright © 2015 Elsevier Ltd. All rights reserved.