Role of Peroxynitrite in Sepsis-Induced Acute Kidney Injury in an Experimental Model of Sepsis in Rats

Abstract

The mechanisms involved in sepsis-induced acute kidney injury (AKI) are unknown. We investigated the role of nitrosative stress in sepsis-induced AKI by studying the effects of manganese (III) tetrakis-(1-methyl-4-pyridyl) porphyrin pentachloride (MnTMPyP), a peroxynitrite decomposition catalyst, and aminoguanidine (AG), a selective nitric oxide synthase 2 (NOS2) inhibitor and peroxynitrite scavenger, on kidney function of rats subjected to cecal ligation and puncture (CLP). Sprague-Dawley rats (weighing 350 [SD, 50] g) were treated with MnTMPyP (6 mg/kg i.p.) or AG (50 mg/kg i.p.) at t = 12 and 24 h after CLP or sham procedure. At t = 36 h, mean arterial pressure and aortic blood flow were measured, and blood and urine samples were obtained for biochemical determinations, including creatinine clearance, fractional excretion of sodium, and neutrophil gelatinase-associated lipocalin concentration in the urine. Kidney tissue samples were obtained for (i) light microscopy, (ii) immunofluorescence and Western blot for 3-nitrotyrosine and NOS2, (iii) gene expression (quantitative real-time polymerase chain reaction) studies (NOS1, NOS2, NOS3, and superoxide dismutase 1), and (iv) matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Mean arterial pressure was unchanged and aortic blood flow decreased 25% in CLP animals. The sepsis-induced (i) decreased urine output and creatinine clearance and increased fractional excretion of sodium and urinary neutrophil gelatinase-associated lipocalin concentration, (ii) increased protein nitration and NOS2 protein, and (iii) NOS1 and NOS2 upregulation were all significantly attenuated by treatment with MnTMPyP or AG. Nitrated proteins in renal tissue from CLP animals (matrix-assisted laser desorption ionization time-of-flight mass spectrometry) were glutamate dehydrogenase, methylmalonate-semialdehyde dehydrogenase, and aldehyde dehydrogenase, mitochondrial proteins involved in energy metabolism or antioxidant defense. Nitro-oxidative stress is involved in sepsis-induced AKI, and protein nitration seems to be one mechanism involved.

Oxidative stress parameters and inflammatory and immune mediators as markers of the severity of sepsis

“…Oxidative stress (oxidant/antioxidant imbalance) also plays an important role in the pathophysiology of sepsis. Previous human and animal studies confirmed severe oxidative stress in patients with sepsis, demonstrating increased oxidant markers and decreased antioxidant capacity [11][12][13][14][15][16]. Our results are consistent with the literature.…”

Role of Mitochondrial DNA in Septic AKI via Toll-Like Receptor 9

“…Mitochondrial oxidant generation in septic AKI plays an important role in renal tubular injury during sepsis, manifested as ischemic injury. 15,16,[35][36][37] Interestingly, mitochondria-targeted antioxidants could attenuate CLP-induced AKI, independent of systemic blood pressure. 17 Our findings showed that TLR9 deficiency helped to prevent renal mitochondrial injury and the subsequent decrease in renal function after CLP.…”

Vitamin D3 pretreatment alleviates renal oxidative stress in lipopolysaccharide-induced acute kidney injury

“…In addition, reactive nitrogen species (RNS) is involved in sepsis-induced acute kidney injury [15,16]. Several studies showed that antioxidants alleviated sepsis-induced acute kidney injury [17,18].…”