Translocation of glomerular p47phox and p67phox by protein kinase C-beta activation is required for oxidative stress in diabetic nephropathy

Oxidative stress is implicated to play an important role in the development of diabetic vascular complications, including diabetic nephropathy. It is unclear whether oxidative stress is primarily enhanced in the diabetic glomeruli or whether it is merely a consequence of diabetes-induced glomerular injury. To address this issue, we examined diabetic glomeruli to determine whether oxidative stress is enhanced, as well as examined the role of protein kinase C (PKC)-beta activation in modulating NADPH oxidase activity. Urinary 8-hydroxydeoxyguanosine excretion and its intense immune-reactive staining in the glomeruli were markedly higher in diabetic than in control rats, and these alterations were ameliorated by a treatment with a selective PKC-beta inhibitor, ruboxistaurin (RBX; LY333531) mesylate, without affecting glycemia. NADPH oxidase activity, which was significantly enhanced in diabetic glomeruli and the source of reactive oxygen species (ROS) generation, was also improved by RBX treatment by preventing the membranous translocation of p47phox and p67phox from cytoplasmic fraction without affecting their protein levels. Adenoviral-mediated PKC-beta(2) overexpression enhanced ROS generation by modulating the membranous translocation of p47phox and p67phox in cultured mesangial cells. We now demonstrate that oxidative stress is primarily enhanced in the diabetic glomeruli due to a PKC-beta-dependent activation of NADPH oxidase resulting in ROS generation.     

氯沙坦对血管紧张素Ⅱ诱导大鼠肾小管上皮细胞氧化应激反应的作用

目的 探讨血管紧张素I型受体阻断剂氯沙坦对血管紧张素Ⅱ（AngⅡ）诱导的大鼠肾小管上皮细胞氧化应激反应及转化生长因子β1(TGF-β1)产生的影响。 方法 以大鼠肾小管上皮细胞株（NRK-52E）为研究对象,分别给予氯沙坦（10-5 mol/L）和（或）NADPH氧化酶抑制剂联二亚苯碘锚（DPI,10-5 mol/L）预处理1 h后再加入AngⅡ（10-7 mol/L）刺激24 h,同时设立空白培养基作为对照组。实时定量PCR和Western印迹法分别检测4组细胞NADPH 氧化酶p22phox、p47phox、Nox-4 mRNA和蛋白水平及TGF-β1 mRNA水平。用2,7- 二氯荧光素双乙酸盐（H2DCF-DA）作为荧光探针,采用荧光分光光度仪检测细胞内活性氧（ROS）的水平。应用比色法测定细胞上清液中超氧化物歧化酶（SOD）水平。 结果 AngⅡ（10-7 mol/L）刺激细胞15 min后开始产生大量的ROS,至60 min达平台期。单纯AngⅡ刺激1 h后,NRK-52E细胞上清液中SOD水平显著低于对照组（27.31 μU/L 比48.29 μU/L,P < 0.01）;经氯沙坦预处理1 h后再加入AngⅡ刺激1 h细胞上清液中SOD水平升高至36.37 μU/L,与AngⅡ组差异有统计学意义（P < 0.01）。单纯AngⅡ刺激NRK-52E细胞24 h可显著上调NADPH氧化酶p22phox、p47phox和Nox-4 mRNA和蛋白水平,其mRNA水平分别为对照组的5.57倍、5.55倍和9.41倍（均P < 0.01）,蛋白水平分别为对照组的4.53倍、4.17倍和6.50倍（均P < 0.01）。经氯沙坦干预后,p22phox、p47phox和Nox-4 mRNA水平分别为对照组的2.71倍、2.18倍和5.23倍（均P < 0.01）,蛋白水平分别为对照组的3.20倍、2.30倍和4.30倍（均P < 0.01）。AngⅡ刺激细胞24 h后TGF-β1 mRNA表达也显著增多,为对照组的4.36倍（P < 0.01）,氯沙坦处理细胞后TGF-β1 mRNA水平为对照组的1.57倍。 结论 氯沙坦通过抑制NADPH氧化酶的表达和增加SOD的表达减少ROS的产生,并能通过减少ROS产生,抑制AngⅡ诱导的TGF-β1 mRNA水平增高。     

In high glucose protein kinase C-zeta activation is required for mesangial cell generation of reactive oxygen species

BACKGROUND: We postulated that in mesangial cells exposed to high glucose, protein kinase C-zeta (PKC-zeta) is necessary for the generation of reactive oxygen species (ROS) by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and that the requirement of PKC-zeta for filamentous (F)-actin disassembly may involve ROS. To identify signaling mechanisms relevant to PKC-zeta activation and ROS generation, including phosphoinositide 3 kinase (PI3 kinase), we examined mesangial cell stimulation with platelet-derived growth factor (PDGF). METHODS: In primary rat mesangial cells cultured in 5.6 mmol/L or 30 mmol/L d-glucose, PKC-zeta expression was identified with immunoblotting and activity was analyzed in cell membrane immunoprecipitates and by confocal immunofluorescence imaging. ROS generation was measured by dichlorofluorescein fluorescence using confocal microscopy and was inhibited by transfection of antisense against NADPH subunits p22(phox) or p47(phox) or with Tempol. F-actin disassembly was observed by dual-channel confocal fluorescence imaging. PI3 kinase activity was detected by immunoblotting of phosphorylated Akt. RESULTS: In high glucose, generation of NADPH oxidase-dependent ROS was dependent on PKC-zeta. Conversely, sustained PKC-zeta activity was dependent on ROS generation, suggesting a positive feedback. PKC-zeta-dependent F-actin disassembly in high glucose required ROS generation. PDGF stimulated NADPH oxidase generation of ROS through a PKC-zeta mechanism that was independent of Akt phosphorylation and remained unchanged in high glucose. CONCLUSION: In high glucose, mesangial cell PKC-zeta is required for ROS generation from NADPH oxidase similar to PDGF stimulation of PKC-zeta-dependent ROS generation through a pathway independent of PI3 kinase. F-actin disassembly in high glucose also requires ROS. A positive feedback loop occurs between ROS and the activation of PKC-zeta in high glucose.     

Homocysteine activates NADH/NADPH oxidase through ceramide-stimulated Rac GTPase activity in rat mesangial cells

BACKGROUND: We recently demonstrated that homocysteine (Hcys) increases superoxide (O2-) production via NADH/NADPH oxidase in renal mesangial cells. This O2- production contributes to increased expression of tissue inhibitor of metalloproteinase (TIMP-1) and consequent deposition of collagen in response to Hcys. However, the mechanism by which Hcys activates NADH/NADPH oxidase remains unknown. Given that ceramide is an intracellular activator of this oxidase in several cell types, the present study tests the hypothesis that Hcys activates NADH/NADPH oxidase through a ceramide-mediated signaling pathway in rat mesangial (MG) cells, resulting in O2- production. METHODS: Rat MG cells were incubated with L-homocysteine (L-Hcys) to determine the mechanism by which Hcys activates NADH/NADPH oxidase. Thin layer chromatography (TLC), Western blot analysis, Rac GTPase activity pull down assay, and NADH/NADPH oxidase activity measurements were performed. RESULTS: TLC analysis demonstrated that L-Hcys increased de novo production of ceramide in MG cells. L-Hcys and increased ceramide did not alter the amount of NADH/NADPH oxidase subunit p47phox and p67phox in both membrane and cytosolic fractions from MG cells. However, L-Hcys or ceramide markedly increased the level of GTP-bound Rac, which was accompanied by enhanced activity of NADH/NADPH oxidase. These Hcys or ceramide-induced actions were substantially blocked by a Rac GTPase inhibitor, GDPbetaS, and a de novo ceramide synthesis inhibitor, fumonisin B1 (FB1). CONCLUSION: These results indicate that Hcys activates NADH/NADPH oxidase by stimulating de novo ceramide synthesis, and subsequently enhancing Rac GTPase activity in rat MG cells. This ceramide-Rac GTPase signaling pathway may mediate Hcys-induced oxidative stress in these glomerular cells.     

表没食子儿茶素没食子酸酯对高糖环境下体外小鼠足细胞活性氧的影响

目的　观察不同浓度表没食子儿茶素没食子酸酯（EGCG）对高糖造成氧化应激状态下体外小鼠足细胞损害的作用并探讨其机制。 方法　以高糖（25 mmol/L）培养的小鼠足细胞为研究对象,维生素E培养为对照。首先以MTT法检测细胞活力,再在激光共聚焦显微镜下以CM-H2DCFDA荧光探针观察不同浓度EGCG（0.2、10、100 μmol/L）刺激足细胞6、12、24 h后活性氧（ROS）生成,并以流式细胞仪定量分析ROS平均荧光强度。RT-PCR法检测足细胞内ROS产生的主要通路NADPH氧化酶各亚基mRNA（ph22phox、p47phox、p67phox）的表达。 结果　高糖刺激下6 h,足细胞ROS生成显著增加（P < 0.01）。正常糖组和甘露醇组培养12 h ROS生成无显著增加（P > 0.05）。EGCG 0.2 μmol/L作用6 h可显著降低高糖环境下体外小鼠足细胞ROS水平（P < 0.01）。与高糖组比较,EGCG（100 μmol/L）显著减少NADPH氧化酶亚基p22phox和p67phox mRNA表达（均P < 0.05）。与维生素Ｅ组比较,EGCG（0.2 μmol/L）和维生素E（0.2 mmol/L）协同作用组显著减少p47phox mRNA表达（P < 0.05）。 结论　EGCG能缓解高糖环境下体外足细胞氧化应激状态,对高糖培养下足细胞有保护作用。     

NADPH氧化酶介导血管紧张素Ⅱ诱导的腹膜间皮细胞转分化及细胞外基质积聚

目的 探讨NADPH氧化酶在血管紧张素(Ang)Ⅱ诱导的腹膜间皮细胞转分化以及细胞外基质积聚中的作用。 方法 体外培养SD大鼠原代腹膜间皮细胞，静止24 h后，随机分为以下4组：正常对照组，AngⅡ（10^-7 mol/L）组，AngⅡ+ Los(洛沙坦,10 μmol/L)组及AngⅡ+DPI（NADPH氧化酶活性抑制剂，10 μmol/L）组。应用荧光染料（DCF）及激光共聚焦显微镜检测细胞内活性氧（ROS）的产生。RT-PCR检测NADPH氧化酶亚单位p47phox以及纤溶酶原激活物抑制剂（PAI）1、α平滑肌肌动蛋白（SMA）、E钙黏蛋白（cadherin） mRNA的表达。Western印迹检测p47phox、α-SMA的蛋白表达。 结果 （1）外源性AngⅡ可显著增加大鼠腹膜间皮细胞ROS的产生，刺激15 min后，ROS 的表达较对照组上升了(3.64±0.53)倍。DPI和洛沙坦可显著抑制AngⅡ刺激后ROS的产生（P < 0.05）。（2）AngⅡ刺激腹膜间皮细胞后， NADPH氧化酶亚单位p47phox mRNA和蛋白的表达均呈上升趋势。洛沙坦和DPI可阻断由AngⅡ诱导的p47phox表达上调（P < 0.05）。（3） AngⅡ诱导α-SMA表达的上调以及 E-cadherin mRNA的下调, 洛沙坦和DPI可部分逆转AngⅡ的这种作用。（4）AngⅡ刺激8 h后可明显上调PAI-1的mRNA表达，为正常对照组的（3.06±0.77）倍。 洛沙坦和DPI可明显阻断PAI-1的表达上调（P < 0.05）。 结论 NADPH氧化酶依赖产生的ROS介导了AngⅡ诱导的腹膜间皮细胞转分化及细胞外基质积聚。阻断AngⅡ的作用及抑制NADPH氧化酶的表达和活性可作为防治腹膜纤维化的潜在治疗靶点。     

氧化应激及丝裂原活化蛋白激酶在醛固酮加盐诱导肾脏损害中的作用

目的 探讨氧化应激与丝裂原活化蛋白激酶（MAPKs)在醛固酮加盐诱导肾脏损伤中的作用。 方法 SD大鼠随机分为以下5组: ⑴ 0.5%乙醇作为对照组； ⑵ 1%氯化钠+0.5%乙醇（氯化钠组）； ⑶ 1%氯化钠+醛固酮+0.5%乙醇（醛固酮组）；⑷ 1%氯化钠+醛固酮+0.5%乙醇+依普利酮（依普利酮组），⑸ 1%氯化钠+醛固酮+0.5%乙醇+超氧化物歧化酶模拟物tempol（tempol组）。实时定量PCR检测肾皮质NADPH氧化酶亚基p22phox、Nox-4 和 gp91phox mRNA水平。Western印迹检测肾皮质磷酸化ERK1/2、JNK及ERK5蛋白表达。 结果 与氯化钠组大鼠相比，醛固酮组大鼠的血压[（165±5）比（118±3） mm Hg]及尿蛋白量（24 h） [(101.0±24.0) 比 (9.1±3.0) mg]显著增高(P均 < 0.05)；肾皮质脂类过氧化反应产物（TBARS）水平明显升高[(0.23±0.02) 比 (0.09±0.01) nmol/mg 蛋白，P < 0.05]；肾皮质NADPH氧化酶亚基p22phox、Nox-4和 gp91phox mRNA表达显著升高[分别为氯化钠组的(2.3±0.2)、(4.3±0.8)和(3.0±0.3)倍，P < 0.05]；肾皮质ERK1/2、JNK与ERK5活性显著增高[分别为氯化钠组的(3.3±0.3)、(2.3±0.3)和(3.0±0.2)倍，P < 0.05]。依普利酮或tempol明显降低醛固组大鼠的血压、尿蛋白量（24 h） [依普利酮组和tempol组分别为(10.0±2.0)、(9.3±2.0) mg]以及肾皮质TBARS水平[依普利酮组和tempol组分别为(0.08±0.01)和(0.11±0.03) nmol/mg 蛋白] (P < 0.05)；并使肾皮质组织ERK1/2、JNK及ERK5活性降至接近对照组水平。 结论 氧化应激与MAPKs通路激活在醛固酮加盐诱导的肾脏损伤中发挥重要作用。     

TGF-β1对大鼠腹膜间皮细胞ROS和NADPH氧化酶亚基p67phox表达的影响及黄芪的干预作用

目的:探讨TGF-β1对大鼠腹膜间皮细胞(RPMCs)活性氧(ROS)和NADPH氧化酶亚基p67phox表达的影响及黄芪注射液(AGI)对其的干预作用。方法:体外培养SD大鼠原代腹膜间皮细胞至第二代,静止24h后,随机分为:正常对照组(A组),AGI(2g/ml)组(B组),TGF-β1(10ng/ml)组(C组),TGF-β1+AGI(2g/ml)组(D组,AGI预处理1h)。用荧光染料(DCF)及激光共聚焦显微镜检测细胞内活性氧(ROS)。RT-PCR检测NADPH氧化酶亚基p67phox mRNA的表达;Western印迹检测p67phox的蛋白表达。结果:TGF-β1可显著增加大鼠腹膜间皮细胞ROS产生,刺激20min后,ROS的表达较对照组显著上升(P<0.05)。AGI可显著抑制TGF-β1刺激后ROS的产生(P<0.05);大鼠腹膜间皮细胞经TGF-β1刺激后,NADPH氧化酶亚基p67phox mRNA和蛋白的表达均上升,AGI可抑制TGF-β1诱导的p67phox mRNA和蛋白的表达上调,差异有统计学意义(P<0.05)。结论:TGF-β1可诱导大鼠腹膜间皮细胞产生的ROS增加、NADPH氧化酶亚基p67phox表达上调;AGI可抑制NADPH氧化酶的表达和活性ROS的产生,从而为AGI防治腹膜纤维化提供了理论依据。     

细胞外信号调节蛋白激酶介导醛固酮诱导的肾小球系膜细胞增殖

Objective To determine the role of extracellular signal-regulated kinases (ERK1/2) in aldosterone-induced rat mesangial cells (RMCs) proliferation. Methods RMCs were obtained from intact glomeruli of 4- to 6-week-old Sprague-Dawley rats and characterized according to published methods. RMCs between passages 5 and passages 10 were used. Protein levels of mineralocorticoid receptor(MR) in RMCs were analyzed by Western blotting. The cells were divided into the following groups: control group, PD98059(10 ?滋mol/L) group, eplerenone (1 ?滋mol/L) group, aldosterone (100 nmol/L) group, aldosterone (100 nmol/L) ＋PD98059 (10 ?滋mol/L) group, aldosterone(100 nmol/L)＋eplerenone (1 ?滋mol/L) group. ERK1/2 activity was measured by Western blotting. Cell proliferation of RMCs was evaluated by [3H]-thymidine uptake measurements. Results MR protein expression in RMCs was confirmed by Western blotting. Aldosterone activated ERK1/2, and the maximal ERK1/2 activation induced by aldosterone was at a concentration of 100 nmol/L. Aldosterone (100 nmol/L)-induced activation of ERK1/2 peaked at 10 minutes (P<0.05). Pretreatment with a selective MR antagonist eplerenone (1 ?滋mol/L) significantly attenuated aldosterone-induced ERK1/2 phosphorylation. Aldosterone (100 nmol/L) treatment for 30 hours increased [3H]-thymidine incorporation of RMCs (135%±8% of controls, P<0.05). Cellular proliferation induced by aldosterone could be prevented by pretreatment with eplerenone or an ERK (MEK) inhibitor PD988059. Conclusion Aldosterone induces RMCs proliferation through MR and ERK1/2 activation, which may contribute to the pathogenesis of glomerular mesangial injury.     

Taurine protected kidney from oxidative injury through mitochondrial-linked pathway in a rat model of nephrolithiasis

Hyperoxaluria and crystal deposition induce oxidative stress (OS) and renal epithelial cells injury, both mitochondria and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase are considered as the main sources of reactive oxygen species (ROS). Taurine is known to have antioxidant activity and shows renoprotective effect. We investigate the effect of taurine treatment on renal protection, and the putative source of ROS, in a rat model of calcium oxalate nephrolithiasis. Rats were administered with 2.5% (V/V) ethylene glycol + 2.5% (W/V) ammonium chloride (4 ml/day), with restriction on intake of drinking water (20 ml/day) for 4 weeks. Simultaneous treatment with taurine (2% W/W, mixed with the chow) was performed. At the end of the study, indexes of OS and renal injury were assessed. Renal tubular ultrastructure changes were analyzed under transmission electron microscopy. Crystal deposition in kidney was scored under light microscopy. Angiotensin II in kidney homogenates was determined by radioimmunoassay. Expression of NADPH oxidase subunits p47phox and Nox-4 mRNAs in kidney was evaluated by real time-polymerase chain reaction. The data showed that oxidative injury of the kidney occurred in nephrolithiasis-induced rats. Hyperplasia of mitochondria developed in renal tubular epithelium. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in mitochondria decreased and the mitochondrial membrane showed oxidative injury. Taurine treatment alleviated the oxidative injury of the kidney, improved SOD and GSH-Px activities, as well as the mitochondrial membrane injury, with lesser crystal depositions in the kidney. We could not detect statistical changes in the renal angiotensin II level, and the renal p47phox and Nox-4 mRNAs expression in those rats. The results suggest that mitochondria but not NADPH oxidase may account for the OS and taurine protected kidney from oxidative injury through mitochondrial-linked pathway in this rat model.     

Effects of NADPH oxidase inhibitor in diabetic nephropathy

BACKGROUND: We used apocynin to test the hypothesis that superoxide anion (O(-) (2)) from nicotinamide adenine dinucleotide phosphate (NADPH) oxidase underlies the development of diabetic nephropathy in the rat. METHODS: Rats received apocynin (16 mg/kg/day) from 2 to 8 weeks after inducing diabetes mellitus (DM) with streptozotocin. RESULTS: DM increased excretion of hydrogen peroxide (H(2)O(2)), lipid peroxidation products (LPO), nitric oxide products (NOx), and protein. The kidneys of rats with DM had increased expression of p47phox and gp91phox and endothelial nitric oxide synthase (eNOS), and increased mesangial matrix with expression of fibronectin and collagen I. Apocynin prevented the increase in excretion of H(2)O(2), LPO, and protein in diabetic rats, increased renal NOx generation, and prevented the increased renal expression of gp91phox and the membrane fraction of p47phox, and reverted the mesangial matrix expansion. CONCLUSION: Activation of NADPH oxidase with translocation of p47phox to the membrane underlies the oxidative stress and limited NO generation, despite enhanced eNOS expression in a model of diabetic nephropathy. Apocynin prevents these changes and the associated proteinuria.     

五甲基槲皮素抗静脉移植物狭窄

目的 探讨五甲基槲皮素(PMQ)在体外和体内的抗静脉移植物狭窄作用.方法 体外实验中用血管紧张素Ⅱ(AngⅡ)(0.1μmol/L,24 h)刺激血管平滑肌细胞(VSMC)增殖,同时分别给予0.1、0.3、1.0、3.0、10.0、30.0 μmol/L的PMQ干预,用MTT法测细胞活力,用DCFH-DA测活性氧簇(ROS),用real-time PCR测还原型烟酰胺腺嘌呤二核苷酸磷酸(NADPH)氧化酶亚单位Nox1,p47phox,p22phox的mRNA表达.体内实验中建立大鼠颈部自体静脉移植模型,随机分为模型对照组和给药组.对照组每晨溶剂灌胃,给药组每晨按PMQ 12.5、25.0、50.0mg/kg 3个剂量分别灌胃.于28天后取材测静脉移植物新生内膜和中膜的厚度及面积比.结果 PMQ 0.3 μmol/L开始显著抑制VSMC的活力,减少ROS的产生并显著抑制Nox1、p47phox、p22phox表达,3μmol/L时作用最强.与对照组相比,3个剂量组的PMQ均能显著减小内膜和中膜的厚度及面积比.结论 PMQ有抑制静脉移植物新生内膜增生的作用,可能与其抑制ROS产生和NADPH氧化酶表达有关.     

NADPH氧化酶在次氯酸修饰白蛋白诱导血管内皮细胞炎性反应中的作用

目的 阐明次氯酸修饰白蛋白（HOCl-Alb）诱导血管内皮细胞炎性反应的机制。 方法 用体外制备的HOCl-Alb与人脐静脉内皮细胞共同培养;用光泽精增强化学发光法测定NADPH氧化酶活性;用免疫沉淀和Western印迹法测定p47phox磷酸化及p47phox与p22phox结合;用免疫荧光化学染色法观察p47phox膜迁移;分别用RT-PCR和Western印迹法测定细胞间黏附分子1（ICAM-1） mRNA和蛋白表达。为了解NADPH氧化酶在HOCl-Alb上调ICAM-1表达过程中的作用,在HOCl-Alb刺激细胞前,在细胞培养液中预先加入NADPH氧化酶特异性抑制剂夹竹桃麻素（apocynin）,观察ICAM-1表达的变化。 结果 HOCl-Alb激活NADPH氧化酶具有剂量和时间依赖性,200 mg/L HOCl-Alb刺激15 min使NADPH氧化酶活性增加的量是牛血清白蛋白组的6.16倍（P ＜ 0.01）,并可诱导p47phox磷酸化和膜迁移,及其与p22phox结合。HOCl-Alb上调ICAM-1表达的作用可被夹竹桃麻素抑制,500 μmol/L 夹竹桃麻素对HOCl-Alb诱导的ICAM-1表达的抑制率为68.97%（P ＜ 0.01）。 结论 NADPH氧化酶是HOCl-Alb诱导ICAM-1高表达的重要途径,与血管内皮炎性反应关系密切。     

夹竹桃麻素对高草酸尿症大鼠肾脏氧化应激损伤的保护作用

目的 观察NADPH氧化酶特异抑制剂夹竹桃麻素（apocynin）对高草酸尿症大鼠肾脏氧化应激（OS）损伤的保护作用。 方法 自由饮用含有0.8%乙二醇的水4周建立高草酸尿症SD大鼠模型。大鼠按随机数字表法分为4个组：空白组、高草酸尿症组、apocynin干预组、apocynin对照组。后两组给予apocynin（0.2 g&#8226;kg-1&#8226;d-1）灌胃,对照组给予正常饮水。4周后检测大鼠肾脏OS 指标（尿H2O2和8-异前列腺素）,以及Ccr及肾脏/体质量比值。免疫组化观察NADPH氧化酶亚基p47phox在肾脏中的表达位置。RT-PCR和免疫印迹法分别检测肾组织NADPH氧化酶亚基p47phox、gp91phox、Nox-1 mRNA以及p47phox蛋白的表达水平。 结果 p47phox在各组肾脏中均有广泛的表达,包括肾皮质区、内髓区、外髓区等。与空白组比较,高草酸尿症组大鼠尿H2O2和8-异前列腺素水平显著升高,Ccr降低,肾脏/体质量比值增高（均P < 0.05）;肾脏p47phox、gp91phox和Nox-1 的mRNA表达均显著增加（均P ＜ 0.05）, p47phox蛋白表达也增多（P ＜ 0.01）。apocynin干预治疗可抑制肾脏p47phox、Nox-1 mRNA及p47phox蛋白的表达,但gp91phox mRNA表达未明显减少,而大鼠尿H2O2和8-异前列腺素水平下降,Ccr增加,肾脏/体质量比值减少,但仍高于对照组水平。 结论 NADPH氧化酶是高草酸尿症诱导大鼠肾脏OS损伤过程中活性氧形成的来源之一。使用apocynin抑制NADPH氧化酶活性可部分减轻肾脏的OS损伤程度,保护肾功能。     

醛固酮通过线粒体源性氧化应激促进表皮生长因子受体活化及肾小球系膜细胞增殖

目的 研究活性氧（ROS）在醛固酮（ALDO）诱导的表皮生长因子受体（EGFR）信号通路活化及系膜细胞增殖中的作用并探讨ROS的来源。 方法 体外培养人肾小球系膜细胞,应用3H-胸腺嘧啶（3H-TdR）掺入法和细胞计数测定系膜细胞增殖;荧光探针2,7-二氯二氢荧光素乙酰乙酸（DCFDA）检测细胞内ROS 的产生;Western印迹法检测EGFR活化。 结果 ALDO可显著促进肾小球系膜细胞增殖,应用100 nmol/L ALDO刺激系膜细胞24 h后,3H-TdR掺入量及细胞数分别是基础状态下的2.63倍和2.15倍。盐皮质激素受体（MR）阻断剂依普利酮（EPLE）几乎完全阻断ALDO诱导的系膜细胞增殖（P < 0.01）,而糖皮质激素受体（GR）阻断剂RU-486对ALDO诱导的细胞增殖无显著抑制作用。ALDO明显促进肾小球系膜细胞ROS产生,100 nmol/L ALDO刺激60 min,系膜细胞内ROS释放是对照组的2.14倍,EPLE显著抑制ALDO诱导的系膜细胞ROS产生（P < 0.01）。线粒体复合体 I抑制剂鱼藤酮（ROT）几乎完全阻断ALDO诱导的ROS产生（P < 0.01）,NADPH 氧化酶抑制剂夹竹桃麻素（apocynin）和二联苯碘（DPI）对ALDO诱导ROS产生的抑制率为30%~35%（P < 0.05）,而黄嘌呤氧化酶抑制剂别嘌醇、环氧化酶抑制剂吲哚美辛、脂氧化酶抑制剂去甲二氢化愈创木酸、细胞色素P450氧化酶抑制剂酮康唑以及一氧化氮合成酶抑制剂N-硝基-L-精氨酸甲酯对ALDO诱导的ROS产生均无明显影响。乙酰半胱氨酸（NAC）和ROT对ALDO诱导系膜细胞增殖的抑制率为75%~80%,apocynin和DPI的抑制作用仅为25%~30%。ALDO可显著活化系膜细胞EGFR,ALDO刺激60 min,EGFR活性是对照组的4.95倍,EPLE和NAC几乎完全阻断ALDO诱导的EGFR磷酸化（P < 0.01）,而NAC和EGFR拮抗剂AG1478则阻断ALDO诱导的系膜细胞增殖（P < 0.01）。 结论 ALDO通过氧化应激依赖的EGFR磷酸化促进肾小球系膜细胞增殖,ALDO诱导的系膜细胞氧化应激主要来源于线粒体。     

Sildenafil inhibits the formation of superoxide and the expression of gp47 NAD[P]H oxidase induced by the thromboxane A2 mimetic, U46619, in corpus cavernosal smooth muscle cells

OBJECTIVE: To assess the effect of sildenafil on superoxide formation and p47(phox) (the active subunit of NADPH oxidase) expression in cultured corpus cavernosal smooth muscle cells (CVSMCs). MATERIALS AND METHODS: CVSMCs derived from rabbit penis were incubated with U46619 (thromboxane A2 analogue) with or without sildenafil for 1 or 16 h at 37 degrees C. Superoxide dismutase-inhibitable superoxide formation was assessed using the reduction of ferricytochrome c measured spectrophotometrically, and gp47(phox) assessed using Western blot analysis. The role of NAD[P]H oxidase and cGMP was further studied by using specific inhibitors of each. RESULTS: Superoxide formation was significantly greater in cells incubated with U46619 after 1 and 16 h incubation than in controls, an effect blocked by NADP(H) oxidase inhibitors. These effects of U46619 were inhibited by sildenafil (1 and 10 nmol/L), which in turn were negated by the guanylyl cyclase inhibitor, ODQ; 10 nmol/L sildenafil inhibited p47phox expression induced by U46619. CONCLUSIONS: Sildenafil is a potent inhibitor of superoxide formation in CVSMCs. This effect is mediated through the inhibition of PDE-5 which in turn augments the inhibitory action of the NO-cGMP axis on NAD[P]H oxidase expression and activity. This mechanism constitutes a new pharmacological action of sildenafil, consolidates the potential role of superoxide in ED, and indicates that thromboxane A(2) may be an important mediator of intrapenile oxidative stress.     

Mechanisms of human neutrophil oxidant production after severe injury

BACKGROUND: The purpose of this study was to determine the mechanisms of enhanced oxidant production after severe injury. METHODS: Neutrophils were harvested from patients within 24 hours of admission who had an injury severity score greater than 16. Nonadherent and adherent neutrophil oxidant production was measured after N-formyl-methionyl-leucyl-phenylalanine (fMLP) stimulation. Translocation of cytochrome b558 and cytosolic components p47phox and p67phox were determined by oxidation-reduction spectroscopy and immunoblotting, respectively. Flow cytometry measured integrin expression. Integrin and p47phox colocalization was examined by confocal microscopy. RESULTS: Eighteen patients were studied within 15 +/- 1.4 hours. Four women and 14 men suffered a blunt injury and had a mean injury severity score of 22 (range, 16 to 34). Nonadherent patient neutrophils showed a decrease in fMLP-stimulated oxidant production, whereas adherent neutrophil oxidant production was increased in both the vehicle control and fMLP-stimulated groups. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase components p47phox and cytochrome b558 were mobilized to the plasma membrane, whereas p67phox showed minimal change. Integrin CD11b a chain showed a significant increase in expression. Confocal microscopy showed colocalization of p47phox and a chain CD11b on the plasma membrane of patient neutrophils. CONCLUSIONS: Colocalization of NADPH oxidase components and integrins may regulate the enhanced oxidant production in human neutrophils after severe injury.     

NADPH氧化酶在转化生长因子β1诱导大鼠肾小管上皮细胞转分化中的作用

目的探讨NADPH氧化酶在转化生长因子β1（TGF-β1）诱导大鼠肾小管上皮细胞（NRK-52E）转分化中的作用。方法用TGF-β1（10μg/L）刺激NRK-52E细胞不同时间,观察α-平滑肌肌动蛋白（α-SMA）、E-钙黏蛋白（E-cadherin）、纤溶酶原激活物抑制剂1（PAI- 1）及Ⅰ型胶原（Col-Ⅰ）的表达。部分实验中细胞在TGF-β1刺激前用NADPH氧化酶抑制剂DPI预处理1 h。用激光共聚焦显微镜观察细胞内活性氧（ROS）的产生。用RT-PCR方法检测NADPH氧化酶p22phox、gp91phox、p47phox和p67phox亚单位mRNA的表达。α-SMA、E-cadherin、PAI-1及Col-ⅠmRNA及蛋白的表达分别采用RT-PCR、Western印迹和细胞免疫化学检测。结果TGF-β1可显著上调NADPH氧化酶p67phox亚单位mRNA的表达,8 h及24 h时分别为对照组的2.43倍及3.59倍（P〈0.01）。TGF-β1可显著促进细胞ROS的产生,5 min时已是对照组的2.5倍（P〈0.05）。DPI预处理同时可显著逆转TGF-β1诱导NRK-52E细胞ROS的产生（P〈0.05）、α-SMA的表达上调、E-cadherin的表达下调以及PAI-1和Col-Ⅰ的表达上调。结论TGF-β1可促进NRK-52E细胞增加ROS的产生。ROS介导了TGF-β1诱导NRK-52E细胞的转分化,促进肾脏纤维化。