The effect of thymoquinone on the renal functions following ischemia-reperfusion injury in the rat

Introduction: The aim of this study was to investigate the effect of thymoquinone, an antioxidant phytochemical compound found in the plant Nigella sativa, on the alterations in renal functional parameters following warm renal ischemia-reperfusion injury (IRI) in the rat. Methods: Wistar rats underwent left renal ischemia for 35 minutes. Group-TQ (n=15) received thymoquinone 10 mg/kg/day (dissolved in a vehicle (corn oil) orally by gavage starting 4 days prior to IRI and continued 6 days thereafter when the hemodynamic and tubular renal functions of the right and left kidneys were measured using clearance techniques. Group-Vx (n=15) underwent similar protocol but received only the vehicle. Results: IRI affected all hemodynamic and tubular parameters in the affected kidney. Thymoquinone attenuated the IRI-related alteration in renal functions so when the left ischemic kidney in Group-TQ and Group-Vx were compared, the left RBF and GFR were significantly higher in Group-TQ (2.02±0.39 vs. 1.27±0.21, P=0.04 and 0.33±0.08 vs. 0.18±0.03, P=0.03, respectively). Thymoquinone also improved left renal FE_Na (1.59±0.28 vs. 2.40±0.35, P=0.04). In addition, it decreased the gene expressions of KIM-1, NGAL, TNF-α, TGF-β1 and PAI-1 (143±20 vs. 358±49, 16±3 vs. 34±6, (1.1±0.2 vs. 2.8±0.4, 1.6±0.1 vs. 2.8±0.1, and 2.4±0.3 vs. 5.8±1.0, P<0.05 for all). Conclusion: Thymoquinone ameliorated the IRI effect on the hemodynamic and tubular renal functional parameters as well as the expression of some kidney injury markers and pro-inflammatory and pro-fibrotic cytokines indicating a renoprotective effect of this agent on the IRI-induced renal dysfunction with potential clinical implications.