Institution: | 1. Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia
Translational Neurodegeneration Laboratory, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia;2. Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia
Division of Nephrology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China;3. Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia;4. Translational Neurodegeneration Laboratory, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia;5. Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, Victoria, Australia;6. Department of Critical Care, Melbourne Medical School, The University of Melbourne, Melbourne, Victoria, Australia
Australian and New Zealand Intensive Care Research Centre, Monash University, Melbourne, Victoria, Australia
Department of Intensive Care, Austin Hospital, Melbourne, Victoria, Australia
Department of Intensive Care, Royal Melbourne Hospital, Melbourne, Victoria, Australia |
Abstract: | Aim Renal medullary hypoperfusion and hypoxia precede acute kidney injury (AKI) in ovine sepsis. Oxidative/nitrosative stress, inflammation, and impaired nitric oxide generation may contribute to such pathophysiology. We tested whether the antioxidant and anti-inflammatory drug, tempol, may modify these responses. Methods Following unilateral nephrectomy, we inserted renal arterial catheters and laser-Doppler/oxygen-sensing probes in the renal cortex and medulla. Noanesthetized sheep were administered intravenous (IV) Escherichia coli and, at sepsis onset, IV tempol (IVT; 30 mg kg−1 h−1), renal arterial tempol (RAT; 3 mg kg−1 h−1), or vehicle. Results Septic sheep receiving vehicle developed renal medullary hypoperfusion (76 ± 16% decrease in perfusion), hypoxia (70 ± 13% decrease in oxygenation), and AKI (87 ± 8% decrease in creatinine clearance) with similar changes during IVT. However, RAT preserved medullary perfusion (1072 ± 307 to 1005 ± 271 units), oxygenation (46 ± 8 to 43 ± 6 mmHg), and creatinine clearance (61 ± 10 to 66 ± 20 mL min−1). Plasma, renal medullary, and cortical tissue malonaldehyde and medullary 3-nitrotyrosine decreased significantly with sepsis but were unaffected by IVT or RAT. Consistent with decreased oxidative/nitrosative stress markers, cortical and medullary nuclear factor-erythroid-related factor-2 increased significantly and were unaffected by IVT or RAT. However, RAT prevented sepsis-induced overexpression of cortical tissue tumor necrosis factor alpha (TNF-α; 51 ± 16% decrease; p = 0.003) and medullary Thr-495 phosphorylation of endothelial nitric oxide synthase (eNOS; 63 ± 18% decrease; p = 0.015). Conclusions In ovine Gram-negative sepsis, renal arterial infusion of tempol prevented renal medullary hypoperfusion and hypoxia and AKI and decreased TNF-α expression and uncoupling of eNOS. However, it did not affect markers of oxidative/nitrosative stress, which were significantly decreased by Gram-negative sepsis. |