Effect of intravenous H2S on porcine aortic occlusion-induced systemic inflammation and kidney ischemia/reperfusion injury

Abstract

Introduction: Both inhaled hydrogen sulfide (H2S) [1] and intravenous H2S donors protected against kidney ischemia/reperfusion (I/R) injury [2-4], but all these data originate from unresuscitated rodent models. Therefore, we investigated the effect of the H2S donor Na2S in a clinically relevant porcine model of aortic occlusion-induced renal I/R injury. Method(s): Anesthetised and ventilated pigs received Na2S (n = 9) or vehicle (n = 10) for 2 hours before and 8 hours after 90 minutes of intra-aortic balloon occlusion-induced kidney ischemia. During reperfusion noradrenaline was titrated to keep blood pressure at baseline levels. Before Na2, prior to aortic occlusion and at 1, 2, 4 and 8 hours of reperfusion, we measured renal blood flow and function (creatinine clearance and blood levels, fractional Na+ excretion), blood cytokines (TNFalpha, IL-6, IL-1beta) and nitrates, renal tissue DNA damage (comet assay), HO-1 and caspase-3 expression (western blotting), and NF-kappaB activation (EMSA). Histological damage (glomerular tubularisation [5]) was assessed immediately post mortem. Result(s): Na2S pretreatment was associated with a progressive fall in core temperature and significantly lower noradrenaline infusion rates needed to achieve the hemodynamic targets. While renal blood flow and fractional Na+ excretion were comparable, Na2S attenuated the fall in creatinine clearance and the rise in creatinine blood levels, respectively, which coincided with significantly lower IL-6, IL-1beta, and nitrate blood levels. Kidney glomerular and tissue DNA damage were markedly attenuated, whereas NF-kappaB activation was significantly higher in the Na2S-treated animals. Conclusion(s): In a clinically relevant porcine model mimicking aortic cross-clamping-induced kidney I/R injury, Na2S attenuated tissue injury and organ dysfunction as a result of reduced systemic inflammation and oxidative stress. The higher NF-kappaB activation and the unchanged fractional Na+ excretion were most probably due to the drop in temperature [6] and the direct effect of H2S on tubular Na+ absorption [7], respectively.