红景天甙对大鼠肾脏缺血再灌注损伤的保护作用

目的探讨红景天甙对大鼠肾脏缺血再灌注损伤（IRI）的预防和保护作用。方法将32只健康成年SD大鼠随机分成正常对照组、假手术组、缺血再灌注组和红景天甙组4组，每组8只。缺血再灌注组和红景天甙组分别制作肾脏缺血再灌注模型，红景天甙组予以红景天甙预处理。检测血中尿素氮（BUN）和肌酐（Scr）及肾脏中超氧化物歧化酶（SOD）、丙二酰二醛（MDA）和钠钾ATP酶（Na^＋-K^＋ATPase）含量，并用光镜和电镜观察肾脏组织形态学变化。结果红景天甙组血清BUN和Scr水平、肾皮质MDA含量较缺血再灌注组显著降低（P〈0．01），而肾皮质中SOD和Na^＋-K^＋ATPase含量与缺血再灌注组相比显著升高（P〈0．01）；肾组织光镜和电镜观察均见缺血再灌注组肾小球和肾小管上皮细胞损伤明显，而红景天甙组肾小球及肾小管仅见轻微损伤。结论红景天甙能有效降低大鼠肾脏缺血再灌注损伤（IRI），对肾脏IRI有明显的预防和保护作用，为临床上肾脏IRI提供新的预防和治疗思路。     

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.     

Polyenylphosphatidylcholine pretreatment ameliorates ischemic acute renal injury in rats

AIM: Polyenylphosphatidycholine has been demonstrated to have antioxidant, cytoprotective and anti-inflammatory effects. Whether polyenylphosphatidycholine pretreatment affects ischemia/reperfusion-induced renal damage in vivo is not known and was investigated here in rats. METHODS: Forty female Sprague-Dawley rats were divided into three groups. Group 1 (n = 10) was given saline (control, sham operated). Group 2 (n = 15) were given saline, and Group 3 (n = 15) were given polyenylphosphatidycholine (100 mg/day for 10 days prior to experiment). Groups 2 and 3 were subjected to bilateral renal ischemia (60 min) followed by reperfusion (6 h). After the reperfusion period, the rats were sacrificed and kidney tissue superoxide dismutase, glutathione, total nitrite and nitrate, malondialdehyde and myeloperoxidase levels, plasma aspartate aminotransferase, blood urea nitrogen and creatinine concentrations, and nuclear factor kappa beta expression were determined. RESULTS: Serum levels of aspartate aminotransferase, blood urea nitrogen and creatinine were significantly decreased (P < 0.05) in the treatment group compared to those in the ischemic group. There were significant differences between treatment and ischemic groups regarding the tissue superoxide dismutase, glutathione, total nitrite and nitrate, malondialdehyde, and myeloperoxidase levels (P < 0.05). In addition, polyenylphosphatidycholine pretreatment reduced nuclear factor kappa beta expression in ischemic kidney tissue. Kidneys obtained from rats pretreated with polyenylphosphatidycholine demonstrated marked reduction of the histological features of renal injury compared to kidneys obtained from Group 2 rats, including a little vacuolization, pyknosis and necrosis. CONCLUSIONS: Polyenylphosphatidycholine pretreatment provided significant protection against ischemia/reperfusion injury to the kidney. This treatment could be therapeutic in kidney transplantation and other conditions associated with ischemia/reperfusion injury to the kidney.     

Ischemic postconditioning inhibits apoptosis after renal ischemia/reperfusion injury in rat.

Ischemic postconditioning is a phenomenon that intermittent interruptions of blood flow in the early phase of reperfusion can protect organ from ischemia/reperfusion (I/R) injury. In the present study, we investigated whether the protective effect of ischemic postconditioning was associated with modulation of apoptosis after renal I/R injury. Rats were subjected to 45 min of renal ischemia, both with and without treatment with ischemic postconditioning. Serum urea nitrogen and creatinine levels, phosphorylation of Akt and ERK1/2 and apoptosis were compared after renal injury. Our data showed that ischemic postconditioning attenuated the renal dysfunction and cell apoptosis induced by I/R and increased phosphorylation of Akt and ERK1/2. The results indicated that ischemic postconditioning decreased apoptosis and improved renal function. This protective effect may be related with the levels of Akt and ERK1/2 activation. These findings may have major implications in the treatment of renal transplantation.     

Impact of endogenous hydrogen sulfide on toll-like receptor pathway in renal ischemia/reperfusion injury in rats

Abstract

In this study, we investigated the impact of endogenous hydrogen sulfide (H₂S) on toll-like receptors (TLRs)-mediated inflammatory response and apoptosis in renal ischemia–reperfusion injury (IRI). Twenty-four male Wistar rats were randomly divided into four groups: sham, IR, IR?+?propargylglycine (PAG) and IR?+?hydroxylamine (HA). After right nephrectomy, rats were given saline for the sham and IR group, PAG for the IR?+?PAG group and HA for the IR?+?HA group, through the left renal artery for 20?min. Five minutes after drug administration, all rats except sham underwent 45?min of left renal ischemia followed by 24?h of reperfusion. Kidneys were harvested for histological and biochemical evaluation. Levels of TLRs, downstream signaling molecules and pro-inflammatory cytokines were determined by Western blot or immunohistochemistry. Hematoxylin and eosin (H&E) stained renal sections were used for histological grading of renal injury. Apoptotic cells were detected by TUNEL assay. Compared to the sham group, rats in the IR group showed higher renal levels of TLR-2, TLR-4, nuclear NF-κB p65, phosphorylated ASK1, phosphorylated TRAF2, IL-1β, IL-6, IL-18 and TNF-α (p?<?0.05), and exhibited acute kidney injury (p?<?0.05) and apoptosis (p?<?0.05). Compared to the IR group, rats receiving PAG or HA showed significantly higher levels of TLR-2, TLR-4, nuclear NF-κB p65, phosphorylated ASK1, phosphorylated TRAF2, IL-1β, IL-6, IL-18 and TNF-α (p?<?0.01), more severe acute kidney injury (p?<?0.05) and increased apoptosis (p?<?0.01). Thus, inflammatory response and apoptosis mediated by TLRs are involved in renal IRI. Inhibition of endogenous H₂S significantly activated inflammatory response and apoptosis, and thus promoted renal IRI.     

吸入性麻醉药对肾脏缺血/再灌注损伤的影响

吸入性麻醉药对肾脏缺血/再灌注损伤的保护机制可能是通过亚中毒浓度无机氟化物的直接作用,抑制胞质膜的损伤,对丝裂原活化蛋白激酶家系(MAPKs)的影响,免疫调节和促进热休克蛋白70(HSP-70)合成实现的.而不是通过对肾血流的影响和对肾脏KATP通道的激活作用.     

Mannan-binding lectin mediates renal ischemia/reperfusion injury independent of complement activation

Ischemia/reperfusion injury (IRI) remains a major problem in renal transplantation. Clinical studies have identified that high serum levels of Mannan-binding lectin (MBL), the initiator of the lectin pathway of complement activation, are associated with inferior renal allograft survival. Using a rat model, we identified an entirely novel role for MBL in mediating renal IRI. Therapeutic inhibition of MBL was protective against kidney dysfunction, tubular damage, neutrophil and macrophage accumulation, and expression of proinflammatory cytokines and chemokines. Following reperfusion, exposure of tubular epithelial cells to circulation-derived MBL resulted in internalization of MBL followed by the rapid induction of tubular epithelial cell death. Interestingly, this MBL-mediated tubular injury was completely independent of complement activation since attenuation of complement activation was not protective against renal IRI. Our identification that MBL-mediated cell death precedes complement activation strongly suggests that exposure of epithelial cells to MBL immediately following reperfusion is the primary culprit of tubular injury. In addition, also human tubular epithelial cells in vitro were shown to be susceptible to the cytotoxic effect of human MBL. Taken together, these data reveal a crucial role for MBL in the early pathophysiology of renal IRI and identify MBL as a novel therapeutic target in kidney transplantation.     

Effects of melatonin on the serum levels of pro-inflammatory cytokines and tissue injury after renal ischemia reperfusion in rats

Abstract

We investigated the changes in the serum levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6, the pro-inflammatory cytokines, and the possible effect of melatonin on the modulation of these inflammatory molecules after renal ischemia reperfusion (IR). The study was carried out in the laboratory of Department of Pharmacology. Forty-six male Wistar albino rats were divided into five groups as control (n?=?6), positive control (n?=?4), sham (n?=?12), renal IR (n?=?12), and renal IR melatonin (n?=?12). After 1?h renal pedicle occlusion, the blood samples were taken for the measurement of cytokine levels at second hour of the reperfusion. The rats were sacrificed after 24?h of reperfusion for histopathological evaluation. Melatonin or vehicle was administrated to IR rats. Lipopolysaccharide (LPS) was administered to the positive control group and the blood was taken at fourth hour. Serum TNF-α levels increased significantly in renal IR and LPS groups. Serum IL-6 levels were not different from control except the LPS group. There was no significant correlation between the serum TNF-α levels and the histopathological score after renal IR. Melatonin treatment reversed the increase of serum TNF-α levels and histopathological injury in renal tissue after renal IR. Melatonin may have a protective effect by reducing the serum level of TNF-α in renal IR.     

Prevention of lethal murine pancreas ischemia reperfusion injury is specific for tetrahydrobiopterin

Tetrahydrobiopterin has been shown to efficiently abrogate ischemia reperfusion injury (IRI). However, it is unclear, whether its beneficial action relies on cofactor activity of one of the five known tetrahydrobiopterin-dependent reactions or on its antioxidative capacity. We therefore compared tetrahydrobiopterin with the pterin derivate tetrahydroneopterin (similar biochemical properties, but no nitric oxide synthase cofactor activity) and the antioxidants vitamin C and 5-methyltetrahydrofolate. Donor mice were pretreated with tetrahydrobiopterin, tetrahydroneopterin, vitamin C, or 5-methyltetrahydrofolate. Pancreatic grafts were subjected to 16-h cold ischemia time and implanted in syngeneic recipients. Untreated and nontransplanted animals served as controls. Following 2-h reperfusion, microcirculation was analyzed by intravital fluorescence microscopy. Graft damage was assessed by histology and nitrotyrosine immunostaining, and tetrahydrobiopterin levels were determined by HPLC. Recipient survival served as ultimate readout. Prolonged cold ischemia time resulted in microcirculatory breakdown. Only tetrahydrobiopterin pretreatment succeeded to preserve the capillary net, whereas all other compounds showed no beneficial effects. Along with increased intragraft tetrahydrobiopterin levels during recovery and implantation, only tetrahydrobiopterin pretreatment led to significant reduction of IRI-related parenchymal damage enabling recipient survival. These results show a striking superiority of tetrahydrobiopterin in preventing lethal IRI compared with related compounds and suggest nitric oxide synthases as treatment target.     

丹参与CsA对移植肾缺血再灌注损伤防治作用的对比研究

目的探讨药物对移植肾缺血再灌注损伤(IRI)的防治作用。方法40只健康雄性日本大耳兔随机分为四组:生理盐水对照组、单纯灌注液组、丹参 灌注液组、环孢素A(CsA) 灌注液组。用套管针穿刺左肾动、静脉,形成局部循环,灌注后原位低温保存2h,结扎并切除右肾后使左肾复灌。于术后6、24h分别取血标本,24h后取左肾标本。测定血尿素氮(BUN)、血肌酐(Cr);TUNEL法检测左肾组织的细胞凋亡;免疫组化法测定左肾组织HSP70及NF-κB的表达。结果丹参组和CsA组能有效地改善肾功能(BUN、Cr),前者明显提高超氧化物歧化酶(SOD)活性,减少丙二醛(MDA),而后者明显诱导HSP70的表达。二者均能减少细胞的凋亡。结论IRI是由多因素、多环节共同作用的结果,丹参及CsA能分别从不同方面对IRI进行防治。     

Prevention of renal ischemia/reperfusion-induced injury in rats by leflunomide

OBJECTIVE: There is increasing evidence to suggest that toxic oxygen radicals play an essential role in the pathogenesis of ischemia/reperfusion (I/R) injury in the kidney. This study was designed to investigate the effects of leflunomide, an isoxazole derivative and a unique immunomodulatory agent, in I/R-induced renal injury in rats. METHODS: Forty female Sprague-Dawley rats were divided equally into four groups: (I) control (only leflunomide 10 mg/kg, intragastrically treated); (II) sham operated (only unilateral nephrectomy); (III) I/R; and (IV) leflunomide (10 mg/kg for two doses prior to experiment) plus I/R groups. In groups III and IV, after unilateral nephrectomy, the rats were subjected to 60 min of left renal pedicle occlusion, followed by 6 h of reperfusion. At the end of the reperfusion period, rats were killed and kidneys and blood were removed. Catalase, myeloperoxidase and xanthine oxidase activities, and malondialdehyde, nitric oxide and protein carbonyl levels were determined in renal tissue. Serum creatinine, blood urea nitrogen and aspartate aminotransferase were measured for the evaluation of renal function. In histopathological examination, renal damage was scored 0-3. RESULTS: Group III animals demonstrated severe deterioration of renal function, renal morphology and a significant renal oxidative stress. Pretreatment of animals with leflunomide markedly attenuated renal dysfunction, morphological alterations, reduced elevated oxidative stress products levels and restored the depleted renal antioxidant enzyme. CONCLUSION: The findings imply that oxygen radicals play a causal role in I/R-induced renal injury, and leflunomide exerts renoprotective effects probably by the radical scavenging and antioxidant activities with immunomodulatory effect.     

瘦素在肝缺血/再灌注致肾损伤中作用的研究

目的：研究瘦素（Leptin）在肝缺血/再灌注（I/R）后肾组织中的表达变化,探讨其与肝I/R介导的肾损伤的关系。方法：建立大鼠70%肝I/R模型,设立假手术和缺血60min后再灌注60、150、240、360min组,观察肾脏的病理学变化,检测各组血清尿酸、总抗氧化能力,肾Leptin蛋白及其mRNA表达的变化。结果：与假手术组比较,缺血60min/再灌注150min及再灌注240min组血清尿酸显著升高,以再灌注240min升高最为显著;再灌注240min和360min组血清总抗氧化能力显著升高,以再灌注240min升高最为显著;再灌注150、240和360min组肾Leptin蛋白表达显著升高,再灌注60、240、360min组肾LeptinmRNA表达显著升高,而再灌注150min组LeptinmRNA显著降低。病理学观察提示肝I/R早期的肾损伤较重而后期显著减轻。结论：Leptin在肝I/R后肾组织内的表达变化与肾损伤密切相关,提示它可能作为一种保护因子对抗肝I/R介导的肾损伤。     

Renal damage in rats induced by myocardial ischemia/reperfusion: Role of nitric oxide

BACKGROUND: It has been demonstrated that myocardial ischemia/reperfusion (MI/R) causes renal damage. However, the mechanism underlying this damage in kidneys during revascularization of myocardium is unclear. Direct renal ischemia/reperfusion has been implicated in the induction of inducible nitric oxide synthase (iNOS) that leads to increase production of nitric oxide (NO). Recently, excessive production of NO has been found to be involved in causing renal injury by formatting peroxinitrite (ONOO(-)). The aim of this study was to investigate whether NO has a role in this damage, using aminoguanidine (AMG), a known iNOS inhibitor and an antioxidant, in rats undergoing MI/R. METHODS: Male Wistar rats were used for the experiments (n = 7 each group). In the MI/R group, the left coronary artery was occluded for 30 min and then reperfused for 120 min; the same procedure was used for the AMG group, with the additional step of AMG (200 mg/kg) administered 10 min prior to ischemia. A control group underwent sham operation. At the end of the reperfusion period, all rats were killed and their kidneys removed for biochemical determination and histopathological analysis. RESULTS: Myocardial ischemia/reperfusion in the rat kidney was accompanied by a significant increase in malondialdehyde and NO production, and a decrease in glutathione content. Administration of AMG reduced malondialdehyde and NO production and prevented depletion of glutathione content. These beneficial changes in the biochemical parameters were also associated with parallel changes in histopathological appearance. CONCLUSION: These findings suggest that MI/R plays a causal role in kidney injury and AMG exerts renal-protective effects, probably by inhibiting NO production and antioxidant activities.     

心磷脂与缺血/再灌注损伤

心磷脂（CL）是维持线粒体能量代谢所必需的一种磷脂，参与了众多重要生理过程。此文对CL的结构、合成和转化；在维持线粒体正常功能中的作用；缺血／再灌注（I／R）损伤中的改变以及和线粒体功能的关系等作了逐一阐述，说明CL与I／R损伤导致的细胞死亡关系密切，CL量或性质的改变在细胞凋亡中处于中心地位。     

肝脏缺血再灌注损伤与一氧化氮和内皮素平衡关系的研究

目的　研究一氧化氮 (NO)与内皮素 (ET)平衡关系 (NO/ET)的变化与肝脏缺血再灌注(I/R)损伤的关系。方法　采用鼠肝I/R模型 ,并应用不同工具药物观察血NO/ET比值的变化以及肝损伤的情况。结果　I/R急性期血NO/ET比值降低 (1.5 8± 0 .2 0至 0 .2 9± 0 .0 5 ,P <0 .0 1) ,肝损伤加重。NO供体L 精氨酸 (L Arg)与ET受体拮抗剂TAK 0 44在一定程度上可减轻肝I/R损伤 ,而NO合酶抑制剂L NAME进一步加重了损伤。结论　肝I/R损伤与NO/ET平衡关系破坏有关 ,调节其平衡关系可影响I/R损伤的程度。