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.     

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.     

Posttreatment with Aminoguanidine Attenuates Renal Ischemia/Reperfusion Injury in Rats

Acute renal failure secondary to ischemia/reperfusion (I/R) injury is associated with significant mortality and morbidity. Aminoguanidine (AG), an inducible nitric oxide synthase inhibitor with antioxidant properties, has been reported beneficial in renal I/R injury. The aim of the present study was to investigate the effect of AG on renal I/R injury and compare the effectiveness of different AG treatment modalities. Sprague-Dawley rats were randomly assigned to one of four groups. The control group (n?=?6) received sham operation. The I/R group (n?=?6), AG-I group (n?=?8), and AG-II group (n?=?8) received bilateral renal ischemia for 45 min followed by 24 hours of reperfusion. The AG-I group received AG (50 mg/kg) intraperitoneally four hours and 10 minutes before the induction of ischemia. The AG-II group received AG (50 mg/kg) intraperitoneally four hours and 10 minutes after the initiation of reperfusion. Serum urea and creatinine levels increased significantly in the I/R and AG-I groups compared to the control group. Kidney samples from rats in the I/R and AG-I groups revealed severe tubular damage at histopathological examination. Posttreatment with AG significantly reduced serum urea and creatinine levels and improved histopathological lesions compared with the I/R group. Although pretreatment with AG failed to protect kidneys against I/R injury in this experimental model, posttreatment with AG attenuated renal dysfunction and histopathological changes after I/R injury.     

The Effects of Medical Ozone Therapy on Renal Ischemia/Reperfusion Injury

Introduction: This study was designed to investigate the possible beneficial effects of medical ozone therapy (OT), known as an immunomodulator and antioxidant, on the renal function, morphology, and biochemical parameters of oxidative stress in kidneys subjected to ischemia/reperfusion injury (IRI). Materials and methods: Thirty male Sprague–Dawley rats were classified into three groups: control, renal IRI, and renal IRI + OT. The IRI group was induced by bilateral renal ischemia for 60 min, followed by reperfusion for 6 h. After reperfusion, the kidneys and blood of rats were obtained for histopathologic and biochemical evaluation. Results: Renal IRI increased the tissue oxidative stress parameters (lipid peroxidation, protein oxidation, and nitrite plus nitrate) and decreased the antioxidant enzyme activities (superoxide dismutase and glutathione peroxidase). The serum neopterin levels showed correlation with oxidative stress parameters. All these parameters were brought to control values in the treatment group. Histopathologically, the kidney injury in the treatment group was significantly lesser than in the renal IRI group. Conclusions: Our results clearly showed that OT has beneficial effect to protect kidney against IRI. The serum neopterin levels might be used as a marker to detect the degree of renal IRI.     

Scavenging of Peroxynitrite Reduces Renal Ischemia/Reperfusion Injury

Introduction. Nitric oxide (NO) and peroxynitrite (OONO—) are implicated in the pathophysiology of renal ischemia/reperfusion (I/R). The aim of this study was to investigate and compare the efficiency of S-methylisothiourea (SMT), an iNOS inhibitor, and mercaptoethylguanidine (MEG), a scavenger of peroxynitrite, on renal dysfunction and injury induced by I/R of rat kidney. Materials and Methods. Thirty-two male Sprague-Dawley rats were divided into four groups: sham-operated, I/R, I/R+SMT, and I/R+MEG. Rats were given SMT (10 mg/kg ip) or MEG (10 mg/kg ip) 6 h prior to I/R and at the beginning of reperfusion. 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, 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. SMT and MEG significantly reduced the I/R-induced increases in S_Cr, BUN, and AST. Both SMT and MEG attenuated the tissue NO_x levels, indicating reduced NO production. In addition, SMT and MEG markedly reduced elevated oxidative stress product, restored decreased antioxidant enzymes, and attenuated histological alterations. Interestingly, MEG exerted a greater renoprotective effect than SMT. Conclusions. These data support the finding that iNOS and peroxynitrite are involved in the renal I/R injury, and suggest that a scavenger of peroxynitrite might be more effective than iNOS inhibitors as a therapeutic intervention.     

Adenovirus-Mediated bcl-2 Gene Transfer Inhibits Renal Ischemia/Reperfusion Induced Tubular Oxidative Stress and Apoptosis

Ischemia/reperfusion induces oxidative injury to proximal and distal renal tubular cells. We hypothesize that Bcl-2 protein augmentation with adenovirus vector mediated bcl-2 (Adv-bcl-2) gene transfer may improve ischemia/reperfusion induced renal proximal and distal tubular apoptosis through the mitochondrial control of Bax and cytochrome C translocation. Twenty-four hours of Adv-bcl-2 transfection to proximal and distal tubular cells in vitro upregulated Bcl-2/Bax ratio and inhibited hypoxia/reoxygenation induced cytochrome C translocation, O(2) (-) production and tubular apoptosis. Intra-renal arterial Adv-bcl-2 administration with renal venous clamping augmented Bcl-2 protein of rat kidney in vivo in a time-dependent manner. The maximal Bcl-2 protein expression appeared at 7 days after Adv-bcl-2 administration and the primary location of Bcl-2 augmentation was in proximal and distal tubules, but not in glomeruli. With a real-time monitoring O(2) (-) production and apoptosis analysis of rat kidneys, ischemia/reperfusion increased renal O(2) (-) level, potentiated proapoptotic mechanisms, including decrease in Bcl-2/Bax ratio, increases in caspase 3 expression and poly-(ADP-ribose)-polymerase fragments and subsequent proximal and distal tubular apoptosis. However, Adv-bcl-2 administration significantly enhanced Bcl-2/Bax ratio, decreased ischemia/reperfusion induced O(2) (-) amount, inhibited proximal and distal tubular apoptosis and improved renal function. Our results suggest that Adv-bcl-2 gene transfer significantly reduces ischemia/reperfusion induced oxidative injury in the kidney.     

GM-CSF Promotes Macrophage Alternative Activation after Renal Ischemia/Reperfusion Injury

After kidney ischemia/reperfusion (I/R) injury, monocytes home to the kidney and differentiate into activated macrophages. Whereas proinflammatory macrophages contribute to the initial kidney damage, an alternatively activated phenotype can promote normal renal repair. The microenvironment of the kidney during the repair phase mediates the transition of macrophage activation from a proinflammatory to a reparative phenotype. In this study, we show that macrophages isolated from murine kidneys during the tubular repair phase after I/R exhibit an alternative activation gene profile that differs from the canonical alternative activation induced by IL-4–stimulated STAT6 signaling. This unique activation profile can be reproduced in vitro by stimulation of bone marrow-derived macrophages with conditioned media from serum-starved mouse proximal tubule cells. Secreted tubular factors were found to activate macrophage STAT3 and STAT5 but not STAT6, leading to induction of the unique alternative activation pattern. Using STAT3-deficient bone marrow-derived macrophages and pharmacologic inhibition of STAT5, we found that tubular cell-mediated macrophage alternative activation is regulated by STAT5 activation. Both in vitro and after renal I/R, tubular cells expressed GM-CSF, a known STAT5 activator, and this pathway was required for in vitro alternative activation of macrophages by tubular cells. Furthermore, administration of a neutralizing antibody against GM-CSF after renal I/R attenuated kidney macrophage alternative activation and suppressed tubular proliferation. Taken together, these data show that tubular cells can instruct macrophage activation by secreting GM-CSF, leading to a unique macrophage reparative phenotype that supports tubular proliferation after sterile ischemic injury.     

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.     

Acute Ischemia/Reperfusion Injury After Isogeneic Kidney Transplantation Is Mitigated in a Rat Model of Chronic Renal Failure

The influence of chronic renal failure on renal susceptibility to an acute ischemic insult was evaluated. Recipient Lewis rats were randomly assigned to undergo 5/6 nephrectomy (chronic renal failure, CRF) or sham operation (normal renal function, NRF). After 11 weeks, normal kidneys of Lewis donor rats were transplanted in the recipients. The outcome of the isografts was assessed. Filtration capacity of the isografts in the CRF rats was preserved to approximately one-quarter of its normal capacity on the 1st day post-transplantation, whereas it fell to 0 in the NRF rats. This was reflected by a significantly higher increase in serum creatinine in the latter group. The isografts in the CRF rats had a significantly lower degree of acute tubular necrosis and no increase in the number of macrophages and T lymphocytes in the first 24 h in contrast to the NRF rats. Epithelial regeneration and repair started earlier in the CRF group. In conclusion, the present study indicated that CRF blunted ischemia/reperfusion injury of a transplanted kidney, and that its regeneration capacity was certainly not hampered by the presence of chronic uremia. These results will be the basis for studies on modulation of early leukocyte-endothelial interactions resulting from immunological disturbances inherent to the uremic environment.     

Effects of Intravenous Anesthetics on Renal Ischemia/Reperfusion Injury

Background. Renal ischemia/reperfusion (I/R)-induced tubular epithelial cell injury, called ischemic acute renal failure, is associated with high mortality in humans. Protecting the kidney against I/R injury is very important during complicated renal operations, transplantation surgery, and anesthesia. Aim. The purpose of this study was to investigate and compare the efficiency of ketamine, thiopental, propofol, etomidate, and intralipid in reducing the injury induced by free radicals in a rat model of renal I/R. Method. Forty-two Wistar rats were divided into seven groups in our study. Rats in the sham group underwent laparotomy and waited for 120 minutes (min) without ischemia. Rats in the control group were given nothing with ischemia-reperfusion. Rats in the I/R groups were given ketamine (20 mg/kg), thiopental (20 mg/kg) propofol (25 mg/kg), etomidate (10 mg/kg) and 10% intralipid (250 mg/kg) intraperitoneally 15 min prior to the ischemia for 60 min, followed by reperfusion for 60 min. The blood samples and kidney tissues of the rats were obtained under anesthesia at the end of the reperfusion period. Biochemical malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), blood urea nitrogen (BUN), creatine (Cr), aspartate aminotransferase (AST) were determined, and histopathological analysis was performed with these samples. Results. MDA level was increased significantly in the control group (p < 0.05). Histopathological findings of the control group confirmed that there was renal impairment by tubular cell swelling, interstitial edema, medullary congestion, and tubular dilatation. MDA levels were lower in the ketamine, thiopental, and propofol groups compared to the control group (p < 0.05). In the thiopental and propofol groups, the levels of histopathological scores were significantly lower than control and etomidate groups in ischemia-reperfusion. Conclusion. Our results demonstrated that I/R injury was significantly reduced in the presence of propofol and thiopental. The protective effects of these drugs may belong to their antioxidant properties. These results may indicate that propofol and thiopental anesthesia protects against functional, biochemical, and morphological damage better than control in renal I/R injury.     

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.     

Protection Against Ischemia/Reperfusion Injury in Cardiac and Renal Transplantation with Carbon Monoxide, Biliverdin and Both

Both carbon monoxide (CO) and biliverdin, products of heme degradation by heme oxygenase, have been shown to attenuate ischemia/reperfusion (I/R) injury. We hypothesized in this study that dual-treatment with CO and biliverdin would induce enhanced protective effects against cold I/R injury. Heterotopic heart and orthotopic kidney transplantation were performed in syngeneic Lewis rats after 24-h cold preservation in UW solution. While monotherapy with CO (20 ppm) or biliverdin (50 mg/kg, ip) did not alter the survival of heart grafts, dual-treatment increased survival to 80% from 0% in untreated recipients, with a significant decrease of myocardial injury and improved cardiac function. Similarly, dual-treatment significantly improved glomerular filtration rates of renal grafts and prolonged recipient survival compared to untreated controls. I/R injury-induced up-regulation of pro-inflammatory mediators (e.g. TNF-alpha, iNOS) and extravasation of inflammatory infiltrates were significantly less with dual-treatment than untreated controls. In addition, dual-treatment was effective in decreasing lipid peroxidation and improving graft blood flow through the distinctive action of biliverdin and CO, respectively. The study shows that the addition of byproducts of heme degradation with different mechanisms of action provides enhanced protection against transplant-associated cold I/R injury of heart and kidney grafts.     

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.     

丙泊酚对大鼠缺血再灌注肾NF-κB、TNF-α表达的影响

目的 研究丙泊酚对大鼠肢体缺血再灌注损伤后肾组织中肿瘤坏死因子-α（tumornecrosisfactor-α，TNF-α）、核因子-κB（nuclear factor-κxB，NF-κB）表达的影响。方法 24只SD雄性大鼠，随机分为假手术对照组（A组），肢体缺血再灌注组（B组）和丙泊酚干预组（C组），每组8只。采用免疫组织化学方法检测TNF-α、NF-κB的表达，行图像分析半定量。结果 B组大鼠肾组织中TNF-α、NF-κB的表达明显高于A组（P〈0．05），C组明显低于B组（P〈0．05）。结论 肢体缺血再灌注后有明显肾损伤，丙泊酚对肢体缺血再灌注肾损伤有一定程度的保护作用，其机制可能与下调大鼠肢体缺血再灌注损伤肾组织中TNF-α、NF-κB的过度表达有关。     

Protective Effect of Cordycepin on Experimental Testicular Ischemia/Reperfusion Injury in Rats

Objective: To investigate the role of cordycepin in testicular ischemia/reperfusion injury in rats. Materials and methods: Forty Wistar albino rats were randomly divided into four groups, as follows: group one, control (C); group two, torsion and ischemia (I); group three: detorsion with ischemia–reperfusion (IR); and group four, detorsion/cordycepin. The rats were then analyzed macromorphologically and histopathologically, and blood tests were performed. Specifically, the total oxidant status (TOS) and total antioxidant status (TAS) were determined, and malondialdehyde (MDA), tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β levels were analyzed. In addition, pyknotic nuclei, spermatozoa, edema, and hemorrhage were assessed. Results: When the IR and cordycepin groups were compared with the other groups, there was a statistically significant decrease in TNF-α and MDA levels (p < 0.05). Increased TAS levels were observed in the cordycepin group compared with the control group. TOS levels were significantly increased in the I and IR groups, but decreased in the cordycepin group (p < 0.05). Similar effects were observed in tissue biochemistry analysis. Histopathological evaluations revealed that the spermatozoa count was decreased in the I and IR groups. However, there was an increase in the cordycepin group, as well as a statistically significant difference between the IR and cordycepin groups (p < 0.01). Finally, edema and inflammation were increased in the I and IR groups, but decreased in the cordycepin group. Conclusions: Histological and biochemical findings revealed that cordycepin protected against IR-induced testicular injury.     

Gene Expression Profiling of Acute Liver Stress During Living Donor Liver Transplantation

During liver transplantation, the donor graft is subjected to a number of acute stresses whose molecular basis is not well-understood. The effects of surgical stress, preservation and reperfusion injury were studied in 24 consecutive living donor liver transplant (LDLT) operations. Liver biopsies were taken early in the donor operation (OPENING), after transection of the donor liver (PRECLAMP) and following implantation of the graft (post hepatic artery, [PHA]); these were evaluated for histology, tissue glutathione content and gene expression using a 19K-human cDNA microarray. LDLT was associated with an ischemia/reperfusion injury, with accumulation of small numbers of neutrophils and decreased glutathione in the PHA biopsies. Following reperfusion, the expression of 129 genes increased and 106 genes decreased when compared to OPENING levels (> or <2-fold, p < 0.01). By real-time PCR a subset of 25 genes was verified (15 increased, 10 decreased). These genes were similarly altered in another condition of acute liver stress (the response to brain-death), but not in three chronic liver disease states (HCV, HBV and PBC). This study has identified a set of genes whose expression is altered in acute, but not chronic, liver stress, likely to play a central role in the pathogenesis of acute liver injury of liver transplantation.