Protective effect of resveratrol, a polyphenolic phytoalexin on glycerol-induced acute renal failure in rat kidney

Rhabdomyolysis-induced myoglobinuric acute renal failure (ARF) accounts for about 10% to 40% of all cases of ARF. Reactive oxygen intermediates have been demonstrated to play an etiologic role in myoglobinuric renal failure. This study was designed to investigate the effect of resveratrol, a polyphenolic phytoalexin in glycerol-induced ARF in rats. Seven groups of rats were employed in this study, group I served as control; group II was given 50% glycerol (8 mL/kg, intramuscularly); groups III IV, and V were given glycerol plus resveratrol (2 mg/kg, 5 mg/kg, and 10 mg/kg p.o. route, respectively) 60 min prior to the glycerol injection; group VI received L-NAME (10 mg/kg, i.p.) along with glycerol and resveratrol (5 mg/kg), group VII animals received L-NAME (10 mg/kg) 30 min prior to glycerol administration. Renal injury was assessed by measuring plasma creatinine, blood urea nitrogen, creatinine, and urea clearance. The oxidative stress was measured by renal malondialdehyde levels and reduced glutathione levels, and by enzymatic activity of catalase, glutathione reductase, and superoxide dismutase. Tissue and urine nitrite levels were measured as an index of total nitric oxide levels. Glycero treatment resulted in a marked decrease in tissue and urine nitric oxide levels, renal oxidative stress, and significantly deranged the renal functions along with deterioration of renal morphology. Pre treatment of animals with resveratrol (5 and 10 mg/kg) 60 min prior to glycerol injection markedly attenuated the fall in nitric oxide levels, renal dysfunction, morphologic alterations, reduced elevated thiobarbituric acid reacting substances, and restored the depleted renal antioxidant enzymes. This protection afforded by resveratrol was significantly reversed by cotreatment of L-NAME along with resveratrol, clearly indicating that resveratrol exerts its protective effect through nitric oxide release along with the antioxidative effect in glycerol-induced ARF.     

Protective Effect of Resveratrol,a Polyphenolic Phytoalexin on Glycerol-Induced Acute Renal Failure in Rat Kidney

Rhabdomyolysis-induced myoglobinuric acute renal failure (ARF) accounts for about 10% to 40% of all cases of ARF. Reactive oxygen intermediates have been demonstrated to play an etiologic role in myoglobinuric renal failure. This study was designed to investigate the effect of resveratrol, a polyphenolic phytoalexin in glycerol-induced ARF in rats. Seven groups of rats were employed in this study, group I served as control; group II was given 50% glycerol (8mL/kg, intramuscularly); groups III, IV, and V were given glycerol plus resveratrol (2mg/kg, 5mg/kg, and 10mg/kg p.o. route, respectively) 60 min prior to the glycerol injection; group VI received L-NAME (10mg/kg, i.p.) along with glycerol and resveratrol (5 mg/kg), group VII animals received L-NAME (10 mg/kg) 30 min prior to glycerol administration. Renal injury was assessed by measuring plasma creatinine, blood urea nitrogen, creatinine, and urea clearance. The oxidative stress was measured by renal malondialdehyde levels and reduced glutathione levels, and by enzymatic activity of catalase, glutathione reductase, and superoxide dismutase. Tissue and urine nitrite levels were measured as an index of total nitric oxide levels. Glycerol treatment resulted in a marked decrease in tissue and urine nitric oxide levels, renal oxidative stress, and significantly deranged the renal functions along with deterioration of renal morphology. Pretreatment of animals with resveratrol (5 and 10 mg/kg) 60 min prior to glycerol injection markedly attenuated the fall in nitric oxide levels, renal dysfunction, morphologic alterations, reduced elevated thiobarbituric acid reacting substances, and restored the depleted renal antioxidant enzymes. This protection afforded by resveratrol was significantly reversed by cotreatment of L-NAME along with resveratrol, clearly indicating that resveratrol exerts its protective effect through nitric oxide release along with the antioxidative effect in glycerol-induced ARF.     

Recombinant human erythropoietin reduces rhabdomyolysis-induced acute renal failure in rats

BackgroundRhabdomyolysis is one of the causes of acute renal failure. Erythropoietin (EPO) has been found to interact with its receptor (EPO-R) expressed in a large variety of non-haematopoietic tissues to induce a range of pleiotropic cytoprotective actions. In this study, we used recombinant human erythropoietin (rhEPO) to study the effects on the glycerol-induced rhabdomyolysis with acute renal failure in rats.MethodsTwenty-four rats were divided into three groups as glycerol group, glycerol + EPO group and normal saline + EPO group. Rhabdomyolysis was induced by intramuscular injection of 10 ml kg^?1 50% glycerol in rats. Ten minutes later, the rats received an intravenous injection of rhEPO (300 U kg^?1). Biochemical substances, including haemoglobin, blood urea nitrogen (BUN), creatinine (Cre), glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT) and creatine phosphokinase (CPK), were measured at 0, 1, 3, 6, 9, 12, 18, 24 and 48 h. Rats were sacrificed 48 h later after glycerol administration and the kidneys were removed immediately for pathology and immunohistochemistry (IHC).ResultsIntramuscular injection of glycerol significantly increased blood BUN, Cre, GOT, GPT and CPK levels and induced severe histopathologic damage in the kidneys. Nuclear factor-κB (NF-κB) and inducible nitric oxide synthase (iNOS) were increased and E-cadherin was decreased after glycerol administration, as detected by IHC in the kidneys. Post-treatment with rhEPO decreased blood BUN, Cre, GOT, GPT and CPK levels, decreased markers of kidney injury and suppressed the release of NF-κB and iNOS after rhabdomyolysis.ConclusionTreatment with rhEPO suppressed the activities of NF-κB and iNOS, decreased BUN, Cre, GOT, GPT and CPK levels, and decreased the markers of kidney injury after rhabdomyolysis. These actions ameliorated rhabdomyolysis-induced acute renal failure in rats.     

Theophylline protects against glycerol-induced acute renal failure: Regulation of heme oxygenase-1 and glutathione in rat kidney

Background To investigate the mechanism of glycerol-induced renal injury, we examined kidney levels of the cellular antioxidant glutathione and heme oxygenase-1 (HO-1), the rate-limiting enzyme in heme degradation, after glycerol injection. Methods Male Wistar rats were injected with glycerol to induce acute renal failure. Serum creatinine levels were used as a marker of renal function at 24 hours after glycerol injection. Theophylline and buthionine sulfoximine or vehicle were administered to the rats after glycerol injection, and we determined renal glutathione levels (by biochemical assay) and the levels of HO-1 protein and messenger ribonucleic acid (mRNA; using immunoblot analysis [kidney only]) in various rat organs at 24 hours after glycerol injection. Results Glutathione levels abruptly declined after glycerol injection, reached a minimum at 4 hours, then returned to about two thirds of control levels at 24 hours. HO-1 protein was detected at 4 hours and reached a maximum at 24 hours. The induction of HO-1 protein was observed only in the kidney. HO-1 mRNA was faintly expressed at 2 hours, increased until at least 8 hours, and was not detected 24 hours after the treatment. When theophylline was administered to glycerol-injected rats, renal function improved and glutathione levels increased. In addition, the levels of HO-1 protein decreased, compared with those of glycerol-treated rats not given theophylline. Conclusions These results suggest that theophylline may act by modulating the HO-1 directly or indirectly.     

Carvedilol, an antihypertensive drug with antioxidant properties, protects against glycerol-induced acute renal failure

BACKGROUND/AIMS: The pathogenesis of glycerol-induced myoglobinuric acute renal failure involves, among other causes, ischaemia, vascular congestion and reactive oxygen metabolites. The aim of this study was to investigate the role of carvedilol, an antihypertensive drug with antioxidative potential, in glycerol-induced acute renal failure in rats. METHODS: Three groups of rats were employed in this study. Group 1 served as control, group 2 was given 50% glycerol (8 ml/kg, i.m.) and group 3 was given glycerol plus carvedilol (3 mg/kg, i.p.). Renal injury was assessed by measuring plasma creatinine, blood urea nitrogen, creatinine and urea clearance. The oxidative stress was measured by renal malondialdehyde levels, reduced glutathione levels and enzymatic activity of catalase, glutathione reductase and superoxide dismutase. RESULTS: Glycerol treatment resulted in marked renal oxidative stress and significantly deranged renal functions. Both of these factors were significantly improved by carvedilol treatment. Carvedilol, by its interaction with Fenton reaction chemistry and radical scavenging activity, protected the kidney against the oxidative stress and resultant renal dysfunction produced by glycerol. CONCLUSION: Based on these results, this study indicates the protective effect of carvedilol in this rhabdomyolysis-mimicking model.     

L-Carnitine Ameliorates Glycerol-Induced Myoglobinuric Acute Renal Failure in Rats

There is increasing evidence indicating that oxidative stress plays an important role in the pathogenesis of rhabdomyolysis-induced myoglobinuric acute renal failure (ARF). During times of war and natural disasters, myoglobinuric ARF can assume epidemic proportions. Thus, early and effective renoprotective treatments are of utmost importance. It has been shown that L-carnitine, used as a safe and effective nutritional supplement for more than three decades, is effective in preventing renal injury in many renal injury models involving oxidative stress. The present study was performed to investigate the effects of L-carnitine in an experimental model of myoglobinuric ARF. Four groups of rats were employed in this study: group 1 served as a control; group 2 was given glycerol (10 mL/kg, i.m.); group 3 was given glycerol plus L-carnitine (100 mg/kg, i.p.), starting at the same time as the glycerol injection; group 4 was given glycerol plus L-carnitine (100 mg/kg, i.p.), starting 48h before the glycerol injection. After glycerol injections, the i.p. injections of L-carnitine were repeated every 24h for four days. Ninety-six hours after glycerol injections, blood samples and kidney tissues were taken from the anesthetized rats. Urea and creatinine levels in plasma, N-acetyl-beta-D-glucosaminidase activity in urine, and malondialdehyde levels and catalase enzyme activity in kidney tissue were determined. Histopathological changes and iron accumulation in the kidney tissue were evaluated. In this study, glycerol administration led to marked renal oxidative stress, as well as severe functional and morphological renal deterioration. L-carnitine, possibly via its antioxidant properties, ameliorates glycerol-induced myoglobinuric kidney injury.     

Raf激酶抑制蛋白调控NF-κB信号通路在糖尿病肾脏疾病发病中的作用及药物干预研究

目的 通过检测糖尿病肾脏疾病(DKD)大鼠肾组织Raf激酶抑制蛋白(RKIP)与NF-κB的表达,研究利妥昔单抗(RTX)对DKD大鼠肾组织RKIP表达的影响.方法 SD大鼠按随机数字表法分为正常组、DKD模型组、RTX治疗组(2周组、4周组),各20只.常规法检测血糖及24 h尿蛋白量.Western印迹法检测各组RKIP的表达.免疫组化观察RKIP和NF-κB的表达.结果 DKD模型组血糖及24 h尿蛋白升高(均P＜0.01),大鼠肾小球NF - κB表达显著增高(P＜0.01),RKIP表达降低(P＜0.05).与模型组比较,RTX治疗组大鼠RKIP表达增高(P＜0.05),24 h尿蛋白和肾小球NF-KB表达下降(均P＜0.05).DKD模型组NF-κB与RKIP表达呈负相关.结论 RKIP调节NF-KB途径可能在DKD发生发展中有重要作用.RTX在DKD中可能有一定的治疗作用.     

Ameliorative effect of hepatocyte growth factor on glycerol-induced acute renal failure with acute tubular necrosis

BACKGROUND/AIMS: Hepatocyte growth factor (HGF), a multi-potent growth factor, is known to promote regeneration of damaged renal epithelial cells. Glycerol injection into rats induces severe acute renal failure (ARF) with ischemia and tubular necrosis, a model which shares many features with human ARF or rhabdomyolysis. We investigated the efficacy of HGF in this glycerol-induced ARF rat model. METHODS: ARF was induced by intramuscular injection of glycerol into the hind limbs of male Wistar rats. HGF (0.25 mg/kg/shot) or vehicle was administered intravenously 1 h before and 1, 3, 5, 8, 24 and 36 h after glycerol injection. Biochemical parameters for serum and urine were measured and histological analyses of the kidneys were performed. We also analyzed endogenous HGF expression and phosphorylation of c-Met/HGF receptor in the kidneys of glycerol-induced ARF rats. RESULTS: Glycerol treatment caused severe ARF which invariably led to death of the rats. Repeated administration of HGF protected rats from death caused by severe ARF. Histological analyses revealed that HGF treatment reduced necrosis of tubular cells in the renal cortex. Serum/urine biochemical parameters also showed that renal dysfunction was improved by HGF administration. Intravenous administration of HGF enhanced phosphorylation of the c-Met/HGF receptor and mitogen-activated protein kinase in the kidney. In the vehicle-treated group the renal endogenous HGF concentration decreased and there was no change in c-Met/HGF receptor phosphorylation. CONCLUSION: These results indicate that HGF effectively accelerated the recovery of renal function and improved survival in glycerol-induced ARF rats.     

Inhibition of nuclear factor-kappa B activation reduces glycerol-induced renal injury

BACKGROUND: Glycerol injection induces acute tubular necrosis that can progress to interstitial fibrosis. The oxidative stress seen in glycerol-treated animals can activate the nuclear factor kappa B (NF-kappa B) system. The aim of this study was to investigate the expression of NF-kappa B and mitogen-activated protein kinases (MAPKs) in the renal cortex and to determine its relationship with structural and functional renal changes in rats treated with glycerol or glycerol plus pyrrolidine dithiocarbamate (PDTC), a nonspecific NF-kappa B inhibitor with antioxidant properties. METHODS: Male Wistar rats were injected intramuscularly with 8 ml/kg of either 50% glycerol (n=22), glycerol+PDTC (n=25) or 0.15 M saline (n=10). The rats were killed, and the kidneys removed at 5 or 30 days after injection. mmunohistochemical results were scored according to the extent of staining. Interstitial lesions were evaluated through morphometry. Lipid peroxidation was estimated by measuring malondialdehyde in urine samples from control rats and glycerol-injected rats. RESULTS: By postinjection day 5, glycerol-only treated rats presented transitory increases in plasma creatinine levels, as well as in fractional excretion of sodium and potassium (p<0.001), which were attenuated in glycerol+PDTC treated rats (p<0.05). Cortical expression of macrophages and NF-kappa B was greater in glycerol-treated rats than in controls (p<0.001). Glycerol-induced histological nd immunohistochemical changes were attenuated by the addition of PDTC (p<0.001), which also reduced the glycerol-induced increase in urinary malondialdehyde (MDA) levels (p<0.05). CONCLUSIONS: We conclude that PDTC attenuates glycerol-induced renal injury by reducing NF-kappa B expression and decreasing lipid peroxidation in the renal cortex.     

Stimulation of osteoclastic bone resorption in a model of glycerol-induced acute renal failure: evidence for a parathyroid hormone-independent mechanism

This study was undertaken to evaluate the bone changes occurring in rats with acute renal failure (ARF). Acute renal failure was induced in rats 24 hours after dehydration by an intramuscular injection of glycerol. After induction of ARF, the rats were divided into two groups, one of which underwent parathyroidectomy (PTX). Rats with normal renal function, matched for age and weight, were used as controls and divided into two groups, one of them for PTX. At termination of the study blood and urine chemistry and bone histomorphometry were analyzed. Rats with glycerol-induced ARF developed bone changes compatible with mild hyperparathyroid bone disease, characterized mainly by increased osteoclastic bone resorption when compared with control rats having normal renal function. Rats with normal renal function following PTX developed bone disease showing complete suppression of forming and resorptive parameters. Rats with glycerol-induced ARF and PTX showed abolishment of all bone forming parameters, but a dramatic increase in osteoclastic resorption was apparent. Based on these observations we suggest that, in this model of glycerol-induced ARF, osteoclastic bone resorption may develop in the absence of parathyroid hormone, probably stimulated by other potent osteoclastogenic factors.     

氯沙坦对实验性糖尿病大鼠肾脏的炎症抑制作用

目的：观察氯沙坦对糖尿病大鼠肾脏的炎症抑制作用。方法：采用链脲佐菌素（streptomtoein，STZ）65mg／kg腹腔注射建立糖尿病大鼠模型。试验分正常对照组、模型组、治疗组，后一组于模型成功后1周给予氯沙坦20mg／kg灌胃，共12周。分别测定3组24h尿蛋白排泄量、血肌酐、肾重／体重、血浆C反应蛋白（CRP）及肿瘤坏死因子-α（TNF-α）水平；观察肾脏病理形态学变化；应用免疫组化法检测肾组织T011样受体4（TLR4）、核因子-κB（NF-κB）的蛋白表达；RT-PCR检测肾组织TLR4的核酸表达。结果：模型组与对照组相比：模型组大鼠24h尿蛋白、血肌酐、尿素氮、肾重／体重明显升高，肾小球肥大，细胞增生，PAS阳性物质沉积增多；血CRP、TNF-α含量及肾组织TLR4、NF-κB的表达明显增加。经氯沙坦治疗后大鼠血CRP、TNF-α含量下降，肾组织TLR4、NF-κB的表达亦减弱，治疗前后比较存在差异（P〈0．05）。结论：氯沙坦对糖尿病肾病具有保护作用，其作用机制还可能是通过下调NF-κB、TLR4的表达，降低血浆CRP、TNF-α含量，抑制炎症反应而减少糖尿病肾病损伤。     

Oxidative stress in 5/6 nephrectomized rat model: effect of alpha-lipoic acid

Alpha-lipoic acid (ALA) is a powerful antioxidant, and its effect in ameliorating complications of diabetes mellitus has been widely documented. The aim of this study was to investigate the role of ALA in the disease progression of remnant kidneys (RK). Systolic blood pressure (SBp), hemoglobin, renal function, kidney malondialdehyde (MDA), glutathione (GSH), vitamin E (Vit E) concentrations, p65 nuclear factor (NF)-κB activity, and macrophage infiltration were analyzed in sham and RK rats supplemented with ALA (100 mg/kg body weight, i.p., every other day) or vehicle for 12 weeks. RK rats exhibited increases in SBp, kidney MDA concentration, p65 NF-κB activity, and macrophage infiltration, which were prominent in weeks 4 and 8 and decreased at week 12. RK rats also showed anemia, microalbuminuria, and decreased renal function and kidney GSH and Vit E concentrations. These changes were all attenuated by 8 weeks of ALA treatment compared to RK vehicle group. But the continued ALA treatment after week 8 reversed the beneficial effect on SBp, kidney MDA concentration, p65 NF-κB activity, macrophage infiltration, anemia, microalbuminuria, and renal function, while the beneficial effect was maintained if the treatment was discontinued after week 8. Furthermore, ALA increased albuminuria and kidney MDA concentration in sham animals. In conclusion, ALA administration attenuates oxidative stress, inflammation, and hypertension and delayed the deterioration of kidney function in RK rats with enhanced oxidative stress, while in healthy animals or RK rats with a well-balanced redox state, ALA may act as a pro-oxidant, contributing to renal dysfunction.     

NF-κB抑制剂对糖尿病大鼠肾组织ICAM-1和VEGF表达的影响

目的观察核因子-κB（NF-κB）抑制剂吡咯烷二硫基甲酸酯（PDTC）对糖尿病大鼠肾组织细胞间黏附分子-1（ICAM-1）和血管内皮生长因子（VEGF）表达的影响。方法将30只雄性Wistar大鼠随机分成正常对照组（NC组）、糖尿病模型组（DM组）和PDTC干预组（DP组）,每组10只。用链脲佐菌素腹腔注射诱导糖尿病大鼠模型。第8周末,收集24h尿液,检测各组大鼠尿微量白蛋白,处死大鼠后收集肾组织,使用免疫组织化学方法测定肾组织NF-κB、ICAM-1和VEGF的蛋白表达。结果①与NC组相比,DM组尿微量白蛋白升高,差异有统计学意义（P〈0．05）;与DM组相比,DP组尿微量白蛋白降低,差异有统计学意义（P〈0．05）。②与NC组相比,DM组肾组织NF-κB、ICAM1和VEGF蛋白表达升高,差异均有统计学意义（P〈0．05）;与DM组相比,DP组肾组织NF-κB、ICAM-1和VEGF蛋白表达降低,差异均有统计学意义（P〈0．05）。结论肾组织局部表达的ICAM-1和VEGF可能通过NF-κB途径参与糖尿病肾脏病的发生发展。     

EFFECTS OF MELATONIN ADMINISTRATION TO RATS WITH GLYCEROL-INDUCED ACUTE RENAL FAILURE

Melatonin, the pineal hormone with antioxidative properties was administered to rats with glycerol-induced myoglobinuric acute renal failure (Gly-ARF). This model is characterized by acute tubular necrosis mediated by heme-iron oxidative stress. Rats received melatonin (20 mg/kg) concomitant and 3 h after glycerol injection. Gly-ARF rats showed at 24 h a 78% reduction in glomerular filtration rate, whereas this decrement was significantly reduced to 35% in the melatonin treated Gly-ARF rats. Tubular function evaluated by tubular reabsorption of sodium and lithium was also preserved in melatonin treated rats. The histologic analysis revealed extensive cortical tubular necrosis that was significantly reduced by melatonin treatment. The renal concentration of malondialdehyde (MDA) was increased 6 h after glycerol injection in Gly-ARF and this elevation was prevented when melatonin was administered. Renal concentration of reduced glutathione (GSH) was decreased at 6 h in Gly-ARF and melatonin did not reverse this decrease. It was concluded that melatonin administration attenuated the renal injury in the glycerol model of acute renal failure and reduced kidney oxidative stress through a GSH-independent mechanism.     

Effects of melatonin administration to rats with glycerol-induced acute renal failure

Melatonin, the pineal hormone with antioxidative properties was administered to rats with glycerol-induced myoglobinuric acute renal failure (Gly-ARF). This model is characterized by acute tubular necrosis mediated by heme-iron oxidative stress. Rats received melatonin (20 mg/kg) concomitant and 3 h after glycerol injection. Gly-ARF rats showed at 24 h a 78% reduction in glomerular filtration rate, whereas this decrement was significantly reduced to 35% in the melatonin treated Gly-ARF rats. Tubular function evaluated by tubular reabsorption of sodium and lithium was also preserved in melatonin treated rats. The histologic analysis revealed extensive cortical tubular necrosis that was significantly reduced by melatonin treatment. The renal concentration of malondialdehyde (MDA) was increased 6 h after glycerol injection in Gly-ARF and this elevation was prevented when melatonin was administered. Renal concentration of reduced glutathione (GSH) was decreased at 6 h in Gly-ARF and melatonin did not reverse this decrease. It was concluded that melatonin administration attenuated the renal injury in the glycerol model of acute renal failure and reduced kidney oxidative stress through a GSH-independent mechanism.     

The effects of polymicrobial sepsis with diabetes mellitus on kidney tissues in ovariectomized rats

Objectives: Sepsis model was used to understand the role of sustained hyperglycemia and ovariectomy, either separately or concomitantly, on the response of the activity of the nuclear factor kappa B (NF-κB) and the oxidative response in kidney. Subjects: Polymicrobial sepsis was induced by cecal ligation and puncture (CLP). Diabetes was induced in female rats using administration of alloxan. The rats were divided into five groups: sham control (group 1), ovariectomy (group 2), ovariectomy + sepsis (group 3), ovariectomy + diabetes (group 4), and ovariectomy + diabetic + sepsis (group 5). Results: In kidney tissues, the levels of lipid peroxidation (LPO) and glutathione (GSH) and the activity of catalase (CAT) were higher for groups 3, 4, 5 than the control groups. Superoxide dismutase (SOD) activity was lower for groups 3, 4, 5 than the control groups. We determined that CLP produced injury evident in the kidneys of rats when compared to the control group, whereas the severity of the injury was higher in the diabetes + ovariectomy + CLP group when compared to the CLP group. In immunohistochemical staining, we determined that CLP operation increased NF-κB activation. In the ovariectomized, septic, and diabetic group, NF-κB activation was significantly higher than other groups. Conclusions: Hyperglycemia and ovariectomy severely increased NF-κB activation and oxidant levels with the stages of our sepsis model. Ovariectomy resulted in general changes in metabolism, which are seen in the kidney with diabetes under sepsis conditions.     

益肾胶囊对糖尿病肾病大鼠肾间质Wnt与NF-κB影响的研究

目的:观察益肾胶囊对糖尿病肾病(DN)大鼠模型肾间质Wnt4、磷酸化糖原合成酶激酶-3β(PGSK-3β)及核因子-κB(NF-κB)表达水平的影响。方法:健康雄性Wistar大鼠32只,体重(200±20g),随机选取8只作为正常组,其余予腹腔注射链脲佐菌素,制备糖尿病肾病动物模型,造模成功后随机分成4组:模型组(n=8),益肾胶囊组(n=8)和氯沙坦组(n=8)。连续给药12周。12周末,检测各组大鼠24h尿蛋白定量,血肌酐(Scr)、尿素氮(BUN),取肾组织行HE染色、免疫组化。光镜下观察肾间质病理变化情况,用免疫组化法检测Wnt4、PGSK-3β与NF-κB表达水平,行实时荧光定量(FQ-PCR)法测定肾组织中Wnt4、NF-κBmRNA的表达。结果:12周末,与正常组比较,模型组大鼠24h尿蛋白定量、血Scr、BUN明显增加,肾间质Wnt4、PGSK-3β与NF-κB表达水平明显升高,肾组织Wnt4、NF-κBmRNA表达水平明显升高,差异均有统计学意义(P<0.05)。与模型组比较,益肾胶囊治疗组大鼠24h尿蛋白定量、血Scr、BUN明显减少,肾间质Wnt4、PGSK-3β与NF-κB表达水平明显降低,肾组织Wnt4、NF-κBmRNA表达水平明显降低,差异均有统计学意义(P<0.05)。氯沙坦治疗组与益肾胶囊治疗组比较差异无统计学意义(P>0.05)。结论:益肾胶囊可能通过调节DN肾间质Wnt4、PGSK-3β、NF-κB的表达,影响了NF-κB和Wnt通道的信号转导,延缓了DN的进展。     

Effects of Exogenous Melatonin on Myoglobinuric Acute Renal Failure in the Rats

Free oxygen radicals and nitric oxide (NO) play a crucial role in the pathogenesis of myoglobinuric acute renal failure (ARF). In this study, we aimed to investigate the effect of melatonin, a potent free radical scavenger, on the myoglobinuric ARF formed by injecting hypertonic glycerol intramuscularly (im). The rats were randomly divided into 4 Groups. Rats in Group 1 were given saline and those in Groups 2, 3, and 4 were injected with glycerol (10 mL/kg) im. Concomitant and 24 hours after glycerol injection Group 3 (5 mg/kg) and Group 4 (10 mg/kg) were administrated melatonin intraperitoneally. Forty‐eight hours after the glycerol injection, the blood and kidneys of the rats were taken under anesthesia. Kidney morphology and the levels of urea, creatinine and nitric oxide metabolites (NO_x) in the plasma and the enzyme activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) and the level of malondialdehyde (MDA) in the kidney were determined. In both groups of melatonin administration, there was no protective effect of melatonin. Moreover, melatonin significantly decreased the level of NO. As a result, we suggest that the decreasing effect of melatonin on NO, which is a strong vasodilatator, may further increase the renal ischemia in this model. Thus, melatonin may have worsening rather than beneficial effects on myoglobinuric ARF.     

Effects of exogenous melatonin on myoglobinuric acute renal failure in the rats

Free oxygen radicals and nitric oxide (NO) play a crucial role in the pathogenesis of myoglobinuric acute renal failure (ARF). In this study, we aimed to investigate the effect of melatonin, a potent free radical scavenger, on the myoglobinuric ARF formed by injecting hypertonic glycerol intramuscularly (i.m.). The rats were randomly divided into 4 Groups. Rats in Group 1 were given saline and those in Groups 2, 3, and 4 were injected with glycerol (10 mL/kg) i.m. Concomitant and 24 hours after glycerol injection Group 3 (5 mg/kg) and Group 4 (10 mg/kg) were administrated melatonin intraperitoneally. Forty-eight hours after the glycerol injection, the blood and kidneys of the rats were taken under anesthesia. Kidney morphology and the levels of urea, creatinine and nitric oxide metabolites (NOx) in the plasma and the enzyme activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) and the level of malondialdehyde (MDA) in the kidney were determined. In both groups of melatonin administration, there was no protective effect of melatonin. Moreover, melatonin significantly decreased the level of NO. As a result, we suggest that the decreasing effect of melatonin on NO, which is a strong vasodilatator, may further increase the renal ischemia in this model. Thus, melatonin may have worsening rather than beneficial effects on myoglobinuric ARF.     

Reversal of experimental myoglobinuric acute renal failure with bioflavonoids from seeds of grape

Rhabdomyolysis may account for about 10% of all cases of acute renal failure (ARF). This study was performed to explore the protective influence of proanthocyanidins from seeds of grape in an experimental model of myoglobinuric ARF. Rats were injected with 50% glycerol (8 mL/kg, im) followed immediately and daily in the next three days by ip proanthocyanidins (20 mg/kg) or saline. After 96 h rats were sacrificed and kidney morphology, kidney cortex peptidase activities, and malondialdehyde (MDA) content were determined. A moderate renal failure was produced by glycerol injection with blood urea of 31.8+/-11.0 vs. 7.68+/-0.24 m mol/L, and serum creatinine of 153. +/-38.2 vs. 39.6+/-9.0 micromol/L, in glycerol-induced ARF vs. control rats, respectively. Rats that received proanthocyanidins in addition to glycerol had significantly lower (p < 0.01) blood urea and serum creatinine levels compared to those receiving glycerol alone. These functional differences between the glycerol and glycerol plus proanthocianidins groups were also confirmed histologically. Kidney cortex dipeptidylpeptidase IV (DPP IV) activity was not significantly changed in glycerol-induced ARF, however, markedly increased after proanthocyanidins treatment. Kidney cortex malondialdehyde content was found significantly increased in glycerol-induced ARF over control level, and was markedly reduced by proanthocyanidin treatment. Taken together, these results provide strong evidence for the protective role of proanthocyanidins from seeds of grape in glycerol-induced ARF. The effect is probably due to the antioxidant activity of proanthocyanidins and to increased expression of kidney cortex DPP IV with effective degradation of TNF-alpha. This may provide therapeutic opportunities of preventing and/or treating myoglobinuric ARF in humans.