3-Aminobenzamide,a Poly ADP Ribose Polymerase Inhibitor,Attenuates Renal Ischemia/Reperfusion Injury

Introduction. This study was designed to investigate whether 3-amino benzamide (3-AB), a poly (ADP-ribose) polymerase (PARP) inhibitor, has a protective effect on kidney injury induced by renal ischemia/reperfusion (I/R) by decreasing oxidative and nitrosative stress on renal dysfunction and injury. Materials and Methods. Thirty-two male Sprague-Dawley rats were divided into four groups: sham-operated, sham-operated + 3-AB, I/R, I/R + 3-AB. Rats were given 3-AB (100 mg/kg/day ip) 14 days prior to I/R. I/R and I/R + 3-AB groups underwent 60 min of bilateral renal ischemia followed by 6 h of reperfusion. After reperfusion, kidneys and blood were obtained for evaluation. Superoxide dismutase, glutathione peroxidase, malondialdehide, protein carbonyl content, and nitrite/nitrate level (NO_x) were determined in the renal tissue. Serum creatinine (S_Cr), blood urea nitrogen (BUN), and aspartate aminotransferase (AST) were determined in the blood. Additionally, renal sections were used for histological grade of renal injury. Results. 3-AB significantly reduced the I/R-induced increases in S_Cr, BUN, and AST. In addition, 3-AB markedly reduced elevated oxidative stress product, restored decreased antioxidant enzymes, and attenuated histological alterations. Moreover, 3-AB attenuated the tissue NO_x levels, indicating reduced NO production. Conclusions. 3-AB has beneficial effect on renal glomerular and tubular dysfunction in rats' kidneys subjected to I/R injury. Moreover, 3-AB has ameliorating effect on both oxidative stress and nitrosative stress of the kidneys, which correlated with histopathological evaluation.     

Ameliorative Effects of Proanthocyanidin on Renal Ischemia/Reperfusion Injury

Introduction. Several natural products have been reported to have beneficial effects on ischemia/reperfusion (I/R) injury, particularly from a preventative perspective. Therefore, this study was designed to investigate the efficiency of proanthocyanidin (PA), a natural product derived from grape seed, on renal dysfunction and injury induced by I/R of rat kidney. Materials and Methods. Twenty-four male Sprague-Dawley rats were divided into three groups: sham-operated, I/R, I/R+PA. Rats were given PA (100 mg/kg/day peroral) 7 days prior to I/R. All rats except sham-operated underwent 60 min of bilateral renal ischemia followed by 6 h of reperfusion. After reperfusion, kidneys and blood were obtained for evaluation. Superoxide dismutase, glutathione peroxidase, malondialdehyde, protein carbonyl content, and nitrite/nitrate level (NO_x) were determined in the renal tissue. Serum creatinine (S_Cr), blood urea nitrogen (BUN), and aspartate aminotransferase (AST) were determined in the blood. Additionally, renal sections were used for histological grade of renal injury. Results. PA significantly reduced the I/R-induced increases in S_Cr, BUN, and AST. In addition, PA markedly reduced elevated oxidative stress product, restored decreased antioxidant enzymes, and attenuated histological alterations. Moreover, PA attenuated the tissue NO_x, levels indicating reduced NO production. Conclusions. The pretreatment of rats with PA reduced the renal dysfunction and morphological changes, ameliorated cellular injury, and restored renal antioxidant enzymes caused by renal I/R.     

Comparison of the Efficacy of Melatonin and 1400W on Renal Ischemia/Reperfusion Injury: A Role for Inhibiting iNOS

Introduction. We investigated the roles of melatonin (a powerful antioxidant, iNOS inhibitor, and a scavenger of peroxynitrite) and 1400W (a strong and selective inhibitor of inducible nitric oxide) on renal dysfunction and injury induced by ischemia/reperfusion (I/R) of rat kidney, since oxidative and nitrosative injury are believed to be the major causes. Materials and methods. Thirty-two male Sprague-Dawley rats were divided into four groups of sham-operated, I/R, I/R + Melatonin and I/R + 1400W. Rats were given either melatonin (10 mg/kg) or 1400W (10 mg/kg) in the I/R + Melatonin and I/R + 1400W groups respectively at 6 h prior to ischemia and at the beginning of reperfusion via intraperitoneal route. I/R injury was induced by 60 min of bilateral renal ischemia followed by 6 h of reperfusion. After reperfusion, kidneys and blood were obtained for histopathologic and biochemical evaluation. Results. Melatonin and 1400W had an ameliorative effect on both oxidative and nitrosative stress in the kidneys against renal I/R injury in rats. In addition, melatonin significantly reduced elevated nitro-oxidative stress product, restored decreased antioxidant enzymes and attenuated histological alterations when compared with 1400W. Conclusions. Both Melatonin and 1400W were efficient in ameliorating experimental I/R injury of the kidneys. Moreover, melatonin was more effective than 1400W possibly through inhibiting iNOS as well as scavenging free oxygen radicals and peroxynitrite.     

Lysophosphatidic acid and lovastatin might protect kidney in renal I/R injury by downregulating MCP-1 in rat

Abstract Renal ischemia/reperfusion (I/R) injury is a major cause of renal failure. The aim of our study is to explore the role of lysophosphatidic acid (LPA) and lovastatin on renal I/R injury and its mechanism in the rat. Male Wistar rats were randomly divided into sham-operated group; renal I/R for 0 h, 4 h, 12 h, and 24 h groups; LPA treatment group; and lovastatin treatment group (n = 10). Rats were killed to determine the level of monocyte chemotactic protein-1 (MCP-1) in renal tissue, renal function [serum creatinine (Cr) and blood urea nitrogen (BUN)], and renal histomorphology to evaluate the effectiveness of LPA and lovastatin. Normal renal tissue had a low level of MCP-1. The level of MCP-1 began to rise at 0 h after reperfusion, reached peak value at 4 h, and then gradually fell off. Compared with sham-operated group, MCP-1 was increased in all renal I/R injury groups (p < 0.01). With the extension of reperfusion, Cr and BUN were significantly increased (p < 0.01). There were damages in kidney tubules, renal interstitium, and kidney glomerulus in renal I/R injury groups. Paller's score was significantly increased in all renal I/R injury groups compared with sham-operated group (p < 0.01). LPA and lovastatin reduced the level of MCP-1, Cr, BUN, and damages of renal histomorphology (p < 0.01). The level of MCP-1 in renal tissue dynamically increases in renal I/R injury, indicating that MCP-1 is involved in renal I/R injury. LPA and lovastatin might protect renal function by downregulating MCP-1 in renal I/R injury.     

GW274150, a potent and highly selective inhibitor of iNOS,reduces experimental renal ischemia/reperfusion injury

BACKGROUND: Generation of nitric oxide (NO) by inducible nitric oxide synthase (iNOS) may contribute to renal ischemia/reperfusion (I/R) injury. The aim of this study was to investigate the effects of GW274150, a novel, highly selective, potent and long-acting inhibitor of iNOS activity in rat and mouse models of renal I/R. METHODS: Rats were administered GW274150 (5 mg/kg intravenous bolus administered 30 minutes prior to I/R) and subjected to bilateral renal ischemia (45 minutes) followed by reperfusion (6 hours). Serum and urinary indicators of renal dysfunction, tubular and reperfusion injury were measured, specifically, serum urea, creatinine, aspartate aminotransferase (AST) and N-acetyl-beta-d-glucosaminidase (NAG) enzymuria. In addition, renal sections were used for histologic scoring of renal injury and for immunologic evidence of nitrotyrosine formation and poly [adenosine diphosphate (ADP)-ribose] (PAR). Nitrate levels were measured in rat plasma using the Griess assay. Mice (wild-type, administered 5 mg/kg GW274150, and iNOS-/-) were subjected to bilateral renal ischemia (30 minutes) followed by reperfusion (24 hours) after which renal dysfunction (serum urea, creatinine), renal myeloperoxidase (MPO) activity and malondialdehyde (MDA) levels were measured. RESULTS: GW274150, administered prior to I/R, significantly reduced serum urea, serum creatinine, AST, and NAG indicating reduction of renal dysfunction and injury caused by I/R. GW274150 reduced histologic evidence of tubular injury and markedly reduced immunohistochemical evidence of nitrotyrosine and PAR formation, indicating reduced peroxynitrite formation and poly (ADP-ribose) polymerase (PARP) activation, respectively. GW274150 abolished the rise in the plasma levels of nitrate (indicating reduced NO production). GW274150 also reduced the renal dysfunction in wild-type mice to levels similar to that observed in iNOS-/- mice subjected to I/R. Renal MPO activity and MDA levels were significantly reduced in wild-type mice administered GW274150 and iNOS-/- mice subjected to renal I/R, indicating reduced polymorphonuclear leukocyte (PMN) infiltration and lipid peroxidation. CONCLUSIONS: These results suggest that (1). an enhanced formation of NO by iNOS contributes to the pathophysiology of renal I/R injury and (2). GW274150 reduces I/R injury of the kidney. We propose that selective inhibitors of iNOS activity may be useful against renal dysfunction and injury associated with I/R of the kidney.     

Inhibition of Inducible Nitric Oxide Synthase Ameliorates Myocardial Ischemia/Reperfusion Injury − Induced Acute Renal Injury

Objectives

Acute kidney injury occurs frequently in patients subsequent to coronary artery revascularization or myocardial ischemia and reperfusion (MIR). Hypotension and excessive nitric oxide (NO) production through inducible nitric oxide synthase (iNOS) were implicated in renal injury. On the other hand, NO may have a protective role during early reperfusion. In this study, we aim to compare protective effectiveness of 1400W, a highly selective iNOS inhibitor, and L-NG-nitroarginine methyl ester (L-NAME), a non-specific nitric oxide synthase (NOS) inhibitor, against MIR-induced hemodynamic stabilization and kidney injury.

Methods

Male Sprague-Dawley rats were evenly divided in four groups including sham-operated, MIR, and groups pretreated with 1400W (20 mg/kg, intraperitoneally, [ip]) or L-NAME (30 mg/kg, ip) 15 minutes before MIR. Ischemia was conducted by occluding the left coronary artery for 30 minutes, followed by 120 minutes of reperfusion. We determined the measured aortic pressure (MAP) and assessed kidney injury through serum levels of blood urea nitrogen (BUN), methylguanidine (MG), malondialdehyde (MDA) and NO at different phases during the study.

Results

MAP, decreased during myocardial ischemia, increased during early reperfusion; however, that was abolished with L-NAME pretreatment, and the increase was moderate with 1400W pretreatment. Serum MDA, MG and BUN levels, although relatively unaltered during ischemia, significantly increased after 120 minutes of reperfusion. Treatment with 1400W reduced post-reperfusion MDA and MG levels (P < .05), but the improvement was not significant with L-NAME.

Conclusions

1400W was effective in reducing MIR-induced hemodynamic instability and kidney injury, in contrast to no apparent protection with L-NAME administration.     

Lipoteichoic acid from Staphylococcus aureus reduces renal ischemia/reperfusion injury

BACKGROUND: The aim of this study was to investigate whether in vivo administration of a low, sub-lethal dose of lipoteichoic acid (LTA), a bacterial wall-fragment derived from the Gram-positive bacterium Staphylococcus aureus, protects the kidney against the renal dysfunction and injury caused by ischemia/reperfusion (I/R). METHODS: Male Wistar rats were administered LTA from S. aureus (1 mg/kg, IP). After 24 hours, rats were subjected to bilateral renal ischemia (45 min) followed by reperfusion (6 h). Serum and urinary markers were measured for the assessment of renal function, tubular and reperfusion-injury. Renal sections were used for histological grading of renal injury and for immunohistochemical localization of P-selectin, inducible nitric oxide synthase (iNOS) and nitrotyrosine (indicative of peroxynitrite formation). Kidney myeloperoxidase (MPO) activity and malondialdehyde (MDA) levels were measured for assessment of polymorphonuclear (PMN) cell infiltration and lipid peroxidation, respectively. Nitric oxide (NO) production was determined by measurement of plasma nitrite/nitrate levels. RESULTS: LTA pretreatment significantly reduced renal dysfunction, tubular and reperfusion-injury caused by I/R of the kidney as well as histological evidence of renal injury. LTA also reduced the expression of P-selectin and kidney MPO activity associated with renal I/R. MDA levels were significantly reduced by LTA pretreatment suggesting a reduction in the lipid peroxidation and formation of reactive oxygen species (ROS). LTA pretreatment also markedly reduced both the expression of iNOS and the formation of nitrotyrosine associated with renal I/R. Although LTA significantly reduced plasma nitrite/nitrate levels associated with I/R, nitrite/nitrate levels remained at levels significantly higher than that measured from the plasma obtained from Sham-operated animals. CONCLUSIONS: These data suggest, to our knowledge for the first time, that LTA pretreatment for 24 hours significantly reduces renal I/R injury. We propose that the mechanism of the protective effect involves reduction of the production of NO, ROS and peroxynitrite subsequent to reduced P-selectin and iNOS expression and PMN recruitment. However, although LTA pretreatment resulted in a reduction of iNOS expression and NO production, we hypothesize that the remaining significant levels of NO contribute to the beneficial actions provided by LTA.     

诱导型一氧化氮合酶在舒芬太尼预处理减轻大鼠心肌缺血再灌注损伤中的作用

目的 探讨诱导型一氧化氮合酶(iNOS)在舒芬太尼预处理减轻大鼠心肌缺血再灌注损伤中的作用.方法 成年雄性SD大鼠30只,体重250～330 g,采用随机数字表法,将大鼠随机分为5组(n=6):假手术组(S组)只穿线,不结扎;心肌缺血再灌注组(I/R组)采用结扎左冠状动脉前降支30min,再灌注120 min的方法制备大鼠心肌缺血再灌注损伤模型;舒芬太尼预处理组(SF组)缺血前24 h经尾静脉输注舒芬太尼120μg/kg,输注时间30 min;舒芬太尼预处理+iNOS特异性抑制剂S-甲硫脲组(SF+SMT组)缺血前24 h经尾静脉输注舒芬太尼120μg/kg,缺血前10 min静脉注射SMT 10 mg/kg;SMT组缺血前10 min静脉注射SMT 10 mg/kg.于缺血前30 min、缺血30 min、再灌注120 min时记录HR和MAP,计算RPP(SP× HR).于再灌注120 min时取颈动脉血样2 ml,测定血浆NO浓度,随后取心脏制病理切片,测定缺血危险区(AAR)和梗死区(IS)体积,计算心肌梗死体积(IS/AAR),测定心肌iNOS表达.结果 与S组比较,余4组再灌注120 min时MAP和RPP降低,IS/AAR升高,I/R组和SMT组缺血30 min时MAP和RPP降低(P＜0.05);与I/R组比较,SF组、SF+SMT组和SMT组HR、MAP和RPP差异无统计学意义,SF+SMT组和SMT组IS/AAR和血浆NO浓度差异无统计学意义(P＞0.05),SF组IS/AAR降低,血浆NO浓度和心肌iNOS表达升高(P＜0.05).结论 iNOS参与了舒芬太尼预处理减轻大鼠心肌缺血再灌注损伤的过程.

Abstract：

Objective To investigate the role of inducible nitric oxide synthase (iNOS) in reduction of myocardial ischemia-reperfusion (I/R) injury by sufentanil preconditioning in rats. Methods Thirty adult male SD rats, weighing 250-330 g, were randomly divided into 5 groups ( n =6 each): sham operation group (group S),I/R group, sufentanil preconditioning group (group SF), sufentanil preconditioning + a specific inhibitor of iNOS S-methyl thiourea (SMT) group (group SF+ SMT) and S-methyl thiourea group (group SMT). In I/R,SF,SF+SMT and SMT groups, myocardial I/R was produced by occlusion of left anterior descending coronary artery for 30 min followed by 120 min reperfusion. Group SF received 30 min infusion of sufentanil 120 μg/kg via caudal vein 24 h before ischemia. Group SF + SMT received infusion of sufentanil 120 μg/kg via caudal vein 24 h before ischemia and then SMT 10 mg/kg was injected 10 min before ischemia. In group SMT, SMT 10 mg/kg was injected 10min before ischemia. MAP and HR were recorded at 30 min before ischemia, at 30 min of ischemia and at the end of reperfusion. The rate-pressure product (RPP) was calculated. Arterial blood samples were obtained immediately at the end of reperfusion to determine the plasma concentration of NO. Then the animals were sacrificed and myo cardial tissues were obtained to determine the area at risk (AAR), infarct size (IS) and iNOS expression. IS/AAR was calculated. Results Compared with group S, MAP and RPP were significantly decreased, while IS/AAR was significantly increased at 120 min of reperfusion in the other four groups, and MAP and RPP were significantly decreased at 30 min of ischemia in I/R and SMT groups ( P ＜ 0.05). Compared with group I/R, no significant change was found in HR, MAP and RPP in SF, SF + SMT and SMT groups, and in IS/AAR and plasma NO concentrations in SF + SMT and SMT groups ( P ＞ 0.05), but IS/AAR was significantly decreased, and the plasma NO concentration and iNOS expression were significantly increased in group SF ( P ＜ 0. 05). Conclusion iNOS is involved in reduction of myocardial I/R injury by sufentanil preconditioning in rats.     

Beneficial effects of MnTBAP, a broad-spectrum reactive species scavenger, in rat renal ischemia/reperfusion injury

Background In recent years, several lines of evidence have implicated reactive species as contributors to renal ischemia/reperfusion injury (I/R). This study was designed to investigate the effect of Mn (III) tetrakis (4-benzoic acid) porphyrin (MnTBAP), a broad-spectrum reactive species scavenger, in the prevention of renal I/R injury. Methods Experiments were performed on rats anesthetized with pentobarbital. After tracheotomy, the right femoral artery was cannulated and the mean arterial pressure and heart rate were recorded. A midline laparatomy was performed, and the renal arteries were carefully separated from surrounding tissues. After surgery and a stabilization period (60 min), the animals were randomly assigned to four groups: sham-operated; sham+MnTBAP; I/R; I/R+MnTBAP. In I/R groups, the rats were subjected to bilateral renal artery occlusion for 40 min followed by 6 h reperfusion. Other groups underwent the surgery protocol but did not undergo renal artery occlusion, and were maintained under anesthesia for the duration of the experiment. Rats were administered either MnTBAP (10 mg kg⁻¹, i.v. bolus, 15 min prior to I/R) or saline. Renal function was assessed by plasma creatinine (Cr), blood urea nitrogen (BUN), and aspartate aminotransferase (AST) measurements. The fractional excretion of Na⁺ (FE_Na+) and urinary N-acetyl-β-D-glucosaminidase (NAG) activities were also measured. Renal section damage was evaluated by light microscopy, and oxidative stress status was evaluated by measurements of plasma and renal vitamin E levels. Results We found that MnTBAP significantly reduced the I/R-mediated increases in plasma Cr, BUN, AST, FE_Na+, and NAG and improved the renal tissue histology. Conclusion Our results showed that MnTBAP was effective in preventing the development of I/R-induced renal injury.     

Inhibition of inducible nitric oxide synthase reduces renal ischemia/reperfusion injury

BACKGROUND: Nitric oxide (NO), produced via inducible nitric oxide synthase (iNOS), is implicated in the pathophysiology of renal ischemia/reperfusion (I/R) injury. The aim of this study was to investigate the effects of the iNOS inhibitors L-N6-(1-iminoethyl)lysine (L-NIL) and aminoethyl-isothiourea (AE-ITU) on (a) renal dysfunction and injury mediated by bilateral I/R of rat kidneys in vivo and (b) cytokine-stimulated NO production by primary cultures of rat proximal tubule (PT) cells.METHODS: Male Wistar rats subjected to bilateral renal ischemia (45 min) followed by reperfusion (6 h). Rats were administered either L-NIL (3 mg/kg IV bolus 15 min prior to I/R followed by 1 mg/kg/h throughout I/R) or AE-ITU (1 mg/kg IV bolus 15 min prior to I/R followed by 1 mg/kg/h throughout I/R). Serum and urinary biochemical indicators of renal dysfunction and injury were measured; serum creatinine (SCr, glomerular dysfunction), fractional excretion of Na+ (FENa, tubular dysfunction), serum aspartate aminotransferase (sAST, I/R injury) and urinary N-acetyl-beta-d-glucosaminidase (uNAG, tubular injury). Additionally, renal sections were used for histological grading of renal injury and for immunological evidence of nitrotyrosine formation. Nitrate/nitrate levels in plasma were measured using the Griess assay and used as an indicator of NO production. Primary cultures of rat PT cells were incubated with interferon-gamma(IFN-gamma, 100 IU/mL) and lipopolysaccharide (LPS, 10 microg/mL) for 24 h, either in the absence or presence of increasing concentrations of L-NIL or AE-ITU (0.001 to 1 mmol/L) after which nitrite/nitrate levels were measured using the Griess assay.RESULTS: L-NIL and AE-ITU significantly reduced the I/R-mediated increases in SCr, FENa, sAST and uNAG, indicating attenuation of I/R-mediated renal dysfunction and injury. Specifically, L-NIL and AE-ITU reduced the I/R-mediated glomerular and tubular dysfunction and biochemical and histological evidence of tubular injury. Both L-NIL and AE-ITU attenuated the plasma levels of nitrate (indicating reduced NO production) and the immunohistochemical evidence of the formation of nitrotyrosine. In vitro, L-NIL and AE-ITU both significantly reduced cytokine-stimulated NO production by primary cultures of rat PT cells in a dose-dependent manner.CONCLUSIONS: These results suggest that L-NIL and AE-ITU reduce the renal dysfunction and injury associated with I/R of the kidney, via inhibition of iNOS activity and subsequent reduction of NO (and peroxynitrite) generation. We propose that selective and specific inhibitors of iNOS activity may be useful against the NO-mediated renal dysfunction and injury associated with I/R of the kidney.     

Inhibition of nitric oxide synthase reduces renal ischemia/reperfusion injury

BACKGROUND: The role of nitric oxide (NO) production because of inducible nitric oxide synthase (iNOS) in the pathogenesis of renal ischemia/reperfusion (I/R) injury is unclear. In this study the roles of both iNOS and NO were characterized in a rat model of renal I/R injury. In addition, the effect of iNOS inhibition on renal function was evaluated. METHODS: Sprague-Dawley rats underwent 45 min of left renal ischemia and contralateral nephrectomy followed by various periods of reperfusion and renal function analysis [plasma creatinine, fractional excretion of sodium (FENa), creatinine clearance (CrCl), and measurement of plasma and urine NO levels]. In addition, the effect of treatment with 1400W, a highly selective iNOS inhibitor, was evaluated. RESULTS: Renal dysfunction peaked at 48 h after reperfusion and immunohistochemistry studies revealed iNOS expression in the vasculature (3 h) and renal tubules (48 h) after reperfusion. Renal function improved significantly in treated animals compared to controls [creatinine of 1.1 v. 1.9 mg/dl (P < 0.05) and CrCl of 0.54 v. 0.31 ml/min (P < 0.05), respectively]. In addition, FENa was decreased by 50%, plasma NO levels were significantly lower (32.7 v. 45.7 micromol/L, P < 0.01), and deposition of nitrotyosine in the tubules of treated rats was less than in control animals. CONCLUSIONS: These data support the hypothesis that iNOS and NO are involved in the pathogenesis of renal I/R injury and suggests that use of iNOS inhibitors may be a valuable therapeutic strategy clinical situations where renal I/R may be prevalent.     

The Effect of Dietary Ginger (Zingiber officinals Rosc) on Renal Ischemia/Reperfusion Injury in Rat Kidneys

Oxidative stress has been considered as one of the possible mechanisms of ischemia/ reperfusion (I/R) injury in the kidney. The aim of this study was to analyze the possible protective effect of dietary ginger (Zingiber officinals Rosc), a free radical scavenger, on renal I/R injury in rats. The protective effect of ginger against the damage inflicted by reactive oxygen species (ROS) during renal I/R was investigated in Wistar albino rats using histopathological and biochemical parameters. Thirty rats were randomly divided into five experimental groups (i.e., control, sham-operated, ginger, I/R, and I/R + ginger groups, n = 6 each). The ginger and I/R + ginger groups were fed on the test diet containing 5% ginger. The rats were subjected to bilateral renal ischemia followed by reperfusion in I/R and I/R + ginger groups. At the end of the reperfusion period, rats were sacrificed, and kidney function tests, serum and tissue oxidants and antioxidants, and renal morphology were evaluated. Serum urea, creatinine, and cystatin C (CYC) levels were significantly elevated in the ischemia group, but these levels remained unchanged in the ginger + I/R group compared to the I/R group. Reduction of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) enzyme activity was significantly improved by the treatment with ginger compared to I/R group. Administration of ginger resulted in significant reduction levels of tissue malondialdehyde (MDA), NO, protein carbonyl contents (PCC) in the ginger + I/R group compared with the I/R group. Ginger supplementation in the diet before I/R injury resulted in higher total antioxidant capacity (TAC) and lower total oxidant status (TOS) levels than I/R group. The ginger supplemented diet prior to I/R process demonstrated marked reduction of the histological features of renal injury. The findings imply that ROS play a causal role in I/R-induced renal injury, and ginger exerts renoprotective effects probably by the radical scavenging and antioxidant activities.     

Inhibiting inducible nitric oxide synthase with rutin reduces renal ischemia/reperfusion injury

Background

Nitric oxide (NO) seems to play an important role during renal ischemia/reperfusion (I/R) injury. We investigated whether rutin inhibits inducible nitric oxide synthase (iNOS) and reduces 3-nitrotyrosine (3-NT) formation in the kidneys of rats during I/R.

Methods

Wistar albino rats were nephrectomized unilaterally and, 2 weeks later, subjected to 45 minutes of left renal pedicle occlusion followed by 3 hours of reperfusion. We intraperitoneally administered L-N6-(1-iminoethyl)lysine (L-NIL; 3 mg/kg) for 30 minutes or rutin (1 g/kg) for 60 minutes before I/R. After reperfusion, kidney samples were taken for immunohistochemical analysis of iNOS and 3-NT. We measured plasma nitrite/nitrate and cyclic guanosine monophosphate (cGMP) to evaluate NO levels.

Results

Ischemia/reperfusion caused plasma cGMP to increase significantly. Similarly, plasma nitrite/nitrate was elevated in the I/R group compared with the control group. Histochemical staining was positive for iNOS and 3-NT in the I/R group. Pretreatment with L-NIL or rutin significantly mitigated the elevation of plasma cGMP and nitrite/nitrate. These changes in biochemical parameters were also associated with changes in immunohistochemical appearance. Pretreatment with L-NIL or rutin significantly decreased the incidence and severity of iNOS and 3-NT formation in the kidney tissues.

Conclusion

Our findings suggest that high activity of iNOS causes renal I/R injury, and that rutin exerts protective effects, probably by inhibiting iNOS.     

The antioxidant role of oral administration of garlic oil on renal ischemia–reperfusion injury

Aim: In this study we examined the effect of oral application of garlic form [garlic oil (GO)] on rats after renal ischemia–reperfusion (I/R) injury. Materials and methods: Forty male Wistar albino rats were divided into four groups: control, sham-operated, I/R, and I/R + GO. GO was diluted in water and administered by oral intubation three times each week for 6 weeks. All rats except sham-operated underwent 45 min of bilateral renal ischemia followed by 6 hr of reperfusion. Blood samples and kidney tissues were harvested from the rats, and then rats were killed. Serum urea, creatinine, and cystatin C levels were determined. Total antioxidant capacity (TAC), catalase (CAT), total oxidant status (TOS), oxidative stress index (OSI), myeloperoxidase (MPO), nitrite oxide (NO), and protein carbonyl (PC) levels in kidney tissue and blood were measured. In addition, kidney tissue histopathology was evaluated. Results: The serum urea, creatinine, and cystatin C levels were significantly higher in I/R group compared to I/R + GO group (p < 0.01). The serum and tissue antioxidant markers (TAC, CAT) were significantly lower in I/R group than I/R + GO group (p < 0.01). The serum oxidant markers (TOS, MPO, NO, and PC) were significantly higher in I/R group than I/R + GO group (p < 0.01). Also oral application of GO was effective in decreasing of tubular necrosis score. Conclusion: Based on the present data, we conclude that increased antioxidants and decreased oxidants modulated by oral application of GO attenuated the renal I/R injury.     

Curcumin Treatment Protects Against Renal Ischemia and Reperfusion Injury–Induced Cardiac Dysfunction and Myocardial Injury

ObjectivesRenal ischemia and reperfusion (I/R) injury frequently leads to acute renal failure (ARF) and multiple-organ injury with a substantial morbidity rate. The primary cause of ARF-associated death is, however, cardiac failure instead of renal failure itself, and the pathogenesis of renal I/R-induced cardiac injury is still poorly understood. We evaluated the efficacy of curcumin pretreatment on cardioprotection.MethodsThirty Sprague-Dawley rats were evenly divided into 3 groups of sham-operated control, renal I/R injury, and a curcumin pretreatment group. Renal ischemia was conducted by bilateral occlusions of pedicles for 45 minutes, followed by 3 hours of reperfusion. The cardiac function was assessed by the left ventricular end-systolic-pressure-volume-relation (ESPVR), systolic pressure (SP), ejection fraction (EF), and stroke volume (SV). Myocardial injury was assessed based on creatine kinase muscle brain fraction (CK-MB) and Troponin I (cTnI), and kidney injury was assessed based on blood urea nitrogen (BUN) and creatinine. We also assessed the levels of tumor necrosis factor-α (TNF-α) and malondialdehyde (MDA) in the heart tissues.ResultsSV, EF, and SP reduced moderately during the ischemic phase with no major change in ESPVR. During reperfusion, SV, SP, and ESPVR initially increased, and then steadily decreased. Myocardial and kidney injury were marked by the increases in serum CK-MB and cTnI, and creatinine and BUN level. Curcumin pretreatment ameliorated ESPVR and attenuated injuries of both the heart and kidney resulting from I/R insult.ConclusionsCurcumin pretreatment improved cardiac contractility and attenuated myocardial and renal injury through reducing inflammatory response in the kidney and heart and oxidative stress in the myocardium.     

Nitric oxide regulates expression of sonic hedgehog and hypoxia-inducible factor-1alpha in an experimental model of kidney ischemia-reperfusion

This study was designed to determine the effect of L-arginine on hypoxia inducible factor alpha (HIF-1 alpha) and Sonic hedgehog (Shh) levels considered to be involved in the development of ischemia/reperfusion (I/R) injury. Unilaterally nephrectomized Sprague-Dawley rats were subjected to 60 minutes of left renal ischemia followed by 45 minutes of reperfusion. Group 1 were sham-operated animals; group 2, I-R/Untreated animals; and group 3, I-R/L-Arg-treated animals. Serum creatinine, blood urea nitrogen (BUN), and kidney malondialdehyde (MDA) levels were determined as well as examining the kidneys histologically. The treatment of rats with L-Arg produced a significant reduction in the levels of BUN, creatinine, MDA, and histopathological score compared to renal I/R groups. The Shh expression in the tubulus epithelia were intensely increased in the I-R/L-Arg group when compared to that of the Sham-control and the I-R/untreated groups. Additionally, the HIF-1alpha expression in the tubulus epithelia and the interstitial spaces were intensely increased in the I-R/L-Arg group. These findings suggest that NO reduces the renal dysfunction associated with I/R of the kidney and may act as a trigger to induce Shh and HIF-1 activity.     

Nitric Oxide Regulates Expression of Sonic Hedgehog and Hypoxia-Inducible Factor-1α in an Experimental Model of Kidney Ischemia-Reperfusion

This study was designed to determine the effect of L-arginine on hypoxia inducible factor alpha (HIF-1 α) and Sonic hedgehog (Shh) levels considered to be involved in the development of ischemia/reperfusion (I/R) injury. Unilaterally nephrectomized Sprague-Dawley rats were subjected to 60 minutes of left renal ischemia followed by 45 minutes of reperfusion. Group 1 were sham-operated animals; group 2, I-R/Untreated animals; and group 3, I-R/L-Arg-treated animals. Serum creatinine, blood urea nitrogen (BUN), and kidney malondialdehyde (MDA) levels were determined as well as examining the kidneys histologically. The treatment of rats with L-Arg produced a significant reduction in the levels of BUN, creatinine, MDA, and histopathological score compared to renal I/R groups. The Shh expression in the tubulus epithelia were intensely increased in the I-R/L-Arg group when compared to that of the Sham-control and the I-R/untreated groups. Additionally, the HIF-1α expression in the tubulus epithelia and the interstitial spaces were intensely increased in the I-R/L-Arg group. These findings suggest that NO reduces the renal dysfunction associated with I/R of the kidney and may act as a trigger to induce Shh and HIF-1 activity.     

Attenuation of renal ischemia–reperfusion injury by postconditioning involves adenosine receptor and protein kinase C activation

Significant organ injury occurs after transplantation and reflow (i.e., reperfusion injury). Postconditioning (PoC), consisting of alternating periods of reperfusion and re‐occlusion at onset of reperfusion, attenuates reperfusion injury in organs including heart and brain. We tested whether PoC attenuates renal ischemia–reperfusion (I/R) injury in the kidney by activating adenosine receptors (AR) and protein kinase C (PKC). The single kidney rat I/R model was used. Groups: (1) sham: time‐matched surgical protocol only. In all others, the left renal artery (RA) was occluded for 45 min and reperfused for 24 h. (2) Control: I/R with no intervention at R. All antagonists were administered 5 min before reperfusion. (3) PoC: I/R + four cycles of 45 s of R and 45 s of re‐occlusion before full R. (4) PoC + ARi: PoC plus the AR antagonist 8‐ρ‐(sulfophenyl) theophylline (8‐SPT). (5) PoC + PKCi: PoC plus the PKC antagonist chelerythrine (Che). In shams, plasma blood urea nitrogen (BUN mg/dl) at 24 h averaged 23.2 ± 5.3 and creatinine (Cr mg/dl) averaged 1.28 ± 0.2. PoC reduced BUN (87.2 ± 10 in Control vs. 38.8 ± 9, P = 0.001) and Cr (4.2 ± 0.6 in Control vs. 1.5 ± 0.2, P < 0.001). 8‐SPT and Che reversed renal protection indices after PoC. I/R increased apoptosis, which was reduced by PoC, which was reversed by 8‐SPT and Che. Postconditioning attenuates renal I/R injury by adenosine receptor activation and PKC signaling.     

Beneficial Effects of N-Acetylcysteine and Ebselen on Renal Ischemia/Reperfusion Injury

Abstract

Introduction: It has been demonstrated that peroxynitrite accompanies acute renal ischemia and contributes to the pathophysiology of renal damage. Therefore, we aimed to investigate the roles of N-acetylcysteine (NAC), a well-known powerful antioxidant, and ebselen (E), a scavenger of peroxynitrite, on renal injury induced by renal ischemia/reperfusion injury (IRI) of rat kidney. Materials and methods: Forty male Sprague–Dawley rats were divided into five groups: sham, renal IRI, renal IRI+NAC, renal IRI+E, and renal IRI+NAC+E. IR injury was induced by 60 min of bilateral renal ischemia followed by 6 h of reperfusion. After reperfusion, kidneys and blood samples were obtained for histopathological and biochemical evaluations. Results: Renal IR resulted in increased malondialdehyde and nitrite/nitrate levels suggesting increased lipid peroxidation and peroxynitrite production and decreased superoxide dismutase and glutathione peroxidase activities. Both NAC and E alone significantly decreased malondialdehyde and nitrite/nitrate levels and increased superoxide dismutase and glutathione peroxidase activities. Additionally in the renal IRI+NAC+E group, all biochemical results were quite close to those of sham group. Histopathologically, the kidney injury in rats treated with combination of NAC and E was found significantly less than the other groups. Conclusions: Both NAC and E are able to ameliorate IRI of the kidney by decreasing oxidative and nitrosative stresses and increasing free radical scavenger properties. Additionally, combination of NAC and E prevents kidney damage more than when each drug is used alone, suggesting that scavenging peroxynitrite nearby antioxidant activity is important in preventing renal IRI.     

The protective effects of physiological and pharmacological concentrations of melatonin on renal ischemia-reperfusion injury in rats

Reactive oxygen species have been implicated in the pathophysiology of renal ischemia reperfusion (I/R) injury. The pineal secretory product melatonin is known to be a potent free radical scavenger and antioxidant. This study was designed to investigate the effects of physiological and pharmacological concentrations of melatonin on I/R injury. Rats were pinealectomized (Px) or sham-operated (control) 2 months before the I/R studies. There were eight groups of eight rats each. After a right nephrectomy to produce damage, left renal vessels were occluded for 60 min, followed by 24 h reperfusion, in rats. Malondialdehyde (MDA) levels resulting from I/R were significantly higher in the pinealectomized rats than in the control group. Melatonin administration (4 mg kg(-1) i.p. either before ischemia or reperfusion) to Px and sham-operated rats significantly reduced the MDA values and returned them to the control values. Morphological changes in the groups were similar to the MDA levels. Serum levels of blood urea nitrogen and creatine were unchanged. These results suggest that physiological and pharmacological melatonin concentrations are important for the reduction of I/R-induced damage. We also demonstrated that melatonin, even when administrated just before reperfusion, had a protective effect on I/R injury. It would seem valuable to test melatonin in clinical trials for the prevention of possible I/R injury.