Beneficial effects of thiazolidinediones on diabetic nephropathy in OLETF rats

PURPOSE: Diabetic nephropathy is the most serious of complications in diabetes mellitus. Thiazolidinedione (TZD) is thought to ameliorate diabetic nephropathy; however, the mechanism underlying this effect has not been elucidated. We hypothesized that the vascular endothelial growth factor (VEGF) participates in the pathogenesis of diabetic nephropathy and that TZD may be beneficial for the treatment of diabetic nephropathy because of the effect it has on VEGF. MATERIALS AND METHODS: 23 Otsuka- Long-Evans-Tokushima-Fatty (OLETF) rats and eight control Long-Evans-Tokushima-Otsuka (LETO) rats were divided into the following four groups: LETO group, control OLETF group, pioglitazone treated group (10mg/ kg/day), and rosiglitazone treated group (3mg/kg/day). RESULTS: A progressive increase in urinary protein excretion was observed in the diabetic rats. Glomerular VEGF expression in the control OLETF rats was significantly higher than in the control LETO rats. However, there was a significant reduction in both the glomerular VEGF expression and the VEGF mRNA levels after treatment with pioglitazone and rosiglitazone. The twenty-four hour urine protein levels were significantly decreased in both groups of the treated OLETF rats. CONCLUSION: These results suggest that TZD may have beneficial effects on diabetic nephropathy by reducing the VEGF expression.     

Effect of fosinopril on chemerin and VEGF expression in diabetic nephropathy rats

As the most common and severe complication of diabetes, diabetic nephropathy (DN) has been known to be related with angiotensin converting enzyme inhibitor (ACEI), which can reduce proteinuria and protect renal function. This study analyzed the effect of ACEI analog-fosinopril-on the expression of chemerin and vascular epithelial growth factor (VEGF), in an attempt to reveal the mechanism of ACEI analog on renal protection. A total of 45 SD rats were induced by sreptozotocin for diabetes and were given fosinopril via intragastric cannulation for 12 weeks. After sacrifice, serum and renal chemerin and VEGF contents were quantified by enzyme linked immunosorbent assay (ELISA) and Western blot method, in addition to biochemical laboratory examinations. In diabetic model rats, blood glucose, creatinine, urea nitrogen, 24-hour urinary protein, chemerin and VEGF protein contents were all significantly elevated when compared to those in control group (P<0.05). After fosinopril treatment, blood creatinine, urea nitrogen, 24-hour urinary protein, Chemerin and VEGF protein concentrations were significantly depressed (P<0.05 compared to model group). Positive relationships existed between renal chemerin, VEGF and urea protein levels. Fosinopril may protect renal tissues in diabetes by suppressing chemerin and VEGF protein expression.     

低剂量白细胞介素17A对糖尿病肾病大鼠肾功能保护作用的研究

目的 观察并探讨小剂量白细胞介素17A对糖尿病大鼠肾脏的保护作用.方法 雄性SD大鼠45只,随机分3组:正常对照组、DN组及IL-17A组.DN组及IL-17A组均以高脂高糖饮食联合腹腔注射链脲佐菌素建立糖尿病肾病大鼠模型.IL-17A组给予小剂量IL-17A重组蛋白,连续给药12周后,下腔静脉取血,检测糖化血红蛋白、肌酐、尿素氮等;将大鼠放入水平代谢笼中收集各组大鼠24h尿液,测定大鼠24h尿蛋白;实时荧光定量PCR检测肾组织炎症因子表达;Western blot测定IL-17A蛋白表达情况.结果 DN组及IL-17A组尿蛋白、HbA1c、肌酐、尿素氮均显著高于正常对照组(P＜0.05);IL-17A组尿蛋白、肌酐、尿素氮均显著低于DN组(P＜0.05).DN组大鼠在注射IL-17A后促炎因子表达显著减少,抑制性炎症因子表达显著降低.糖尿病肾病模型大鼠IL-17A蛋白显著减少.结论 IL-17A具有改善糖尿病肾病大鼠肾功能作用,并有可能逆转糖尿病肾病,是治疗糖尿病肾病的有效靶点.     

Fgl-2凝血酶原酶介导的微血栓形成在2型糖尿病大鼠肾脏损害中的作用

目的:观察纤维蛋白原样-2(Fgl-2)凝血酶原酶在糖尿病大鼠肾脏中的表达及其病理变化,探讨Fgl-2凝血酶原酶介导的微血栓形成在糖尿病肾脏微血管病变中的作用。方法:实验大鼠随机分为正常对照组(NC组)和2型糖尿病组(T2DM组)。建立T2DM大鼠模型,分别于实验第19周、第23周、第28周处死大鼠,测定24h尿蛋白、血肌酐(Cr)、尿素氮(BUN)、相对肾重;HE、PAS、MASSON染色观察不同病程T2DM组及NC组大鼠的肾脏病理改变,检测大鼠肾脏微血管内血栓形成,计算单位肾小球面积内微血栓所占阳性面积比例;以逆转录PCR方法、免疫组织化学方法测定Fgl-2凝血酶原酶在T2DM大鼠肾脏组织细胞上的表达,并将其表达的平均光密度值与单位肾小球内微血栓阳性面积比例进行相关性分析。结果:T2DM组大鼠Cr、BUN、相对肾重、24h尿蛋白均升高,Fgl-2凝血酶原酶的表达量亦明显增多,主要表达在T2DM大鼠的肾小球毛细血管内皮细胞及肾间质微血管内皮细胞。病理组织学检查显示T2DM大鼠肾小球肥大、系膜扩张、肾小球基底膜增厚、细胞外基质增生、肾小球毛细血管微血栓形成,且微血栓阳性面积比例明显高于NC组。分析显示Fgl-2凝血酶原酶的蛋白表达量与单位肾小球内微血栓阳性面积比例呈正相关。结论:首次发现Fgl-2凝血酶原酶mRNA及蛋白质在T2DM大鼠肾脏中表达上调,与单位肾小球内微血栓阳性面积比例呈正相关,提示Fgl-2凝血酶原酶介导的肾脏内微血栓形成可能促进糖尿病肾病的发生和发展。     

福辛普利对糖尿病大鼠肾组织中Fractalkine及CD68阳性细胞表达的影响

目的探讨福辛普利对糖尿病大鼠肾组织中CX3C类趋化因子Fractalkine和CD68(巨噬细胞标记物)阳性细胞表达的影响及其肾脏保护作用的机制。方法采用免疫组织化学法及RT-PCR检测肾组织中Fractalkine表达,同时采用免疫组织化学法检测肾组织CD68阳性细胞的分布,并对结果进行半定量分析。结果治疗8周后,免疫组织化学法及RT-PCR检测DM组大鼠肾组织中Fractalkine表达增强(P<0.05),肾小球内CD68阳性细胞显著增多,DF组Fractalkine表达明显减弱(P<0.05),同时肾小球内CD68阳性细胞亦显著减少,相关分析显示肾小球CD68阳性细胞数与Fractalkine mRNA表达呈正相关。结论Fractalkine在糖尿病肾组织中表达明显增强,且与肾小球内CD68阳性细胞表达正相关,说明该趋化因子在糖尿病性肾病炎症反应中起重要作用;治疗组大鼠Fractalkine较模型组明显降低,表明福辛普利对肾脏的保护作用可能与下调fractalkine,抑制糖尿病炎症状态有关。     

槲皮素和依那普利对糖尿病大鼠肾组织的PDGF-B和VEGF-1含量的影响研究

了解槲皮素和依那普利对糖尿病大鼠尿蛋白排泄及肾组织的血小板衍生生长因子(PDGF-B)和血管内皮生长因子(VEGF-1)含量的影响。将29只糖尿病大鼠分成3组糖尿病对照组(D组,n=12);依那普利治疗组(E组,n=10);槲皮素治疗组(Q组,n=7)。另有一组正常对照组(N组,n=5)。分别于4、8、12周收集大鼠24h尿测定尿蛋白的量,并于12周处死大鼠并取出肾脏测定PDGF-B和VEGF-1的含量。糖尿病大鼠在8、12周尿蛋白的排泄明显高于正常对照组,E、Q组的尿蛋白量明显低于D组,E组和Q组无明显差异。糖尿病大鼠肾组织中PDGF-B和VEGF-1的含量明显高于正常对照组,E、Q组的PDGF-B和VEGF-1的含量低于D组,E组和Q组无明显差异。槲皮素和依那普利能降低糖尿病大鼠尿蛋白的排泄和肾组织中的PDGF-B和VEGF-1含量。提示槲皮素和依那普利对糖尿病大鼠具有保护作用,这种作用可能与抑制PDGF-B和VEGF-1的产生有关。     

VEGF和HIF-1在糖尿病大鼠坐骨神经的表达及NGF的调节作用

目的探讨血管内皮细胞生长因子(VEGF)及缺氧诱导因子-1(H IF-1)在糖尿病周围神经病变中的表达及神经生长因子的调节作用。方法大鼠糖尿病造模后分成糖尿病(DM)组及神经生长因子(NGF)治疗组,治疗2周后采用蛋白印迹及免疫组化法观察坐骨神经VEGF及H IF-1动态变化。结果蛋白印迹显示正常组坐骨神经纤维无VEGF和H IF-1表达,DM组VEGF及H IF-1表达呈阳性,NGF治疗组无表达。免疫组织化学结果显示,坐骨神经VEGF阳性产物位于轴突及雪旺氏细胞中,DM组积分光密度明显高于正常组及NGF组(P<0.01)。结论局部应用外源性NGF减少糖尿病大鼠坐骨神经VEGF和H IF-1的表达。     

罗格列酮对2型糖尿病大鼠血浆resistin的影响及对肾小球硬化的干预研究

目的： 研究罗格列酮对糖尿病大鼠血清巨噬细胞因子resistin水平的影响,探讨该药物对糖尿病肾小球硬化的干预及可能的作用机制。方法： 20只10周龄Wistar大鼠随机分为糖尿病肾病（DN）模型组和罗格列酮干预组(DN+RSG),另取10只Wistar大鼠作为正常对照组(NC)。DN和罗格列酮干预组大鼠右肾切除后经过阴茎背静脉注射35 mg/kg链脲菌素（STZ）,罗格列酮组按照10 mg·kg-1·d-1的剂量给予罗格列酮灌胃,DN组及正常对照组喂饲普通饮食。STZ注射20周后留取静脉血和24h尿,后处死大鼠并取肾组织。ELISA法检测血浆白细胞介素-1(IL-1)、肿瘤坏死因子-α (TNF-α)及resistin水平,免疫比浊法测定高敏C反应蛋白(hs-CRP),并测定24 h尿微量白蛋白、空腹血糖及肾功能水平。光镜下观察肾组织的病理改变情况,免疫组化检测肾小球转化生长因子-β1(TGF-β1) 的表达,Western blotting检测Smad2磷酸化水平。 结果： 与NC组比较,DN组大鼠血浆炎症因子IL-1、TNF-α、hs-CRP及resistin的水平均显著升高;罗格列酮干预后血浆中上述指标含量均显著低于模型组。与DN组比较,罗格列酮干预组的空腹血糖无明显变化,但24 h尿微量白蛋白定量及肾功能水平均明显下降。罗格列酮干预后肾小球内TGF-β1蛋白表达及Smad2磷酸化水平较DN组显著降低,并且其肾小球系膜增生程度也较DN组明显减轻。结论： 罗格列酮具有延缓及改善糖尿病肾小球硬化的作用,该作用可能与其降低resistin及其它炎症相关因子的表达有关。针对炎症有望控制DN的发生发展。     

糖尿病大鼠肾组织中PTEN/AKT/mTOR通路对自噬的调控作用

目的:观察糖尿病大鼠肾组织中PTEN和自噬水平的变化,探讨糖尿病肾病中PTEN/AKT/m TOR通路对自噬的调控机制。方法:将SD大鼠随机分为正常对照组(NC组)和糖尿病组(DM组),每组各8只。用链脲佐菌素复制DM大鼠模型。于成模后10周处死大鼠后测定相应生化指标和肾脏指数,免疫组化观察肾小管上皮细胞PTEN蛋白的表达部位;Western blotting法检测肾组织LC3、PTEN及PTEN/AKT/m TOR通路的变化;realtime PCR检测肾组织PTEN的mRNA表达水平。结果:DM组的血糖、24 h尿蛋白量和肾脏指数均显著高于NC组(P0.05)。与NC组相比,DM组大鼠肾组织的LC3I和LC3II水平明显降低(P0.05)。PTEN主要分布于肾小管上皮细胞中,DM组PTEN蛋白的表达水平明显低于NC组(P0.05)。DM大鼠肾组织中,PTEN/AKT/m TOR通路的活性增高。结论:糖尿病大鼠肾脏组织中细胞自噬水平下降,而参与自噬调控的PTEN/AKT/m TOR通路活性升高,提示其自噬水平的变化可能受到PTEN/AKT/m TOR通路的调节。     

安体舒通对糖尿病大鼠血管生成素1和血管生成素2表达的影响

目的观察安体舒通对1型糖尿病大鼠肾皮质血管生成素-1(Ang-1)、血管生成素-2(Ang-2)及肾脏血管重建的影响,并初步探讨其机制。方法建立1型糖尿病大鼠模型,用安体舒通干预8周后观察大鼠肾脏血管重建改变,用放射免疫法测定大鼠血浆及肾组织醛固酮水平,用RT-PCR检测各组肾皮质Ang-1和Ang-2mRNA表达。观察安体舒通对上述指标的影响。结果与糖尿病组相比,安体舒通组大鼠肾血管重建改善,血浆及肾组织醛固酮水平更高,Ang-1和Ang-2mRNA表达减少。结论安体舒通通过拮抗醛固酮的作用,减少Ang-1和Ang-2mRNA表达,改善糖尿病肾血管重建从而发挥肾脏保护作用。     

Raf激酶抑制蛋白和p-ERK在糖尿病肾病大鼠肾组织中的表达及意义

 目的:探讨Raf激酶抑制蛋白(Raf kinase inhibitor protein,RKIP)和磷酸化细胞外信号调节激酶(phosphorylated extracellular signal-regulated kinase, p-ERK)在糖尿病肾病大鼠肾组织中的表达及意义。方法:40只Sprague-Dawley （SD）大鼠随机分为2组:正常对照组（N组）和糖尿病肾病组（M组）。苏木精-伊红（hematoxylin-eosin, HE）和过碘酸-雪夫（periodic acid-Schiff,PAS）染色观察肾组织病理改变,免疫组化方法检测各组肾组织RKIP和p-ERK1/2表达,Western blotting 检测各组RKIP和p-ERK1/2的表达。结果:M组大鼠随着病程的延长,血糖升高,出现蛋白尿,肾重增加,肾组织内p-ERK1/2明显增高,RKIP降低,与N组相比有显著差异(P<0.05)。结论: RKIP表达的减少及p-ERK的表达增加可能促进糖尿病肾病的进展。     

吡格列酮对2型糖尿病大鼠肾脏及单核细胞 趋化蛋白 1表达的影响

目的：观察吡格列酮对2型糖尿病(Type 2 diabetes mellitus,T2DM)大鼠血、尿单核细胞趋化蛋白 1（monocyte chemoattractant protein 1,MCP 1）表达及肾脏组织结构和功能的影响。方法：正常对照组(NC组)喂以常规饲料;采用高糖高脂膳食、小剂量链脲佐菌素（streptozotocin,STZ）注射的方法建立2型糖尿病大鼠模型,将成模的大鼠随机分为糖尿病（DM组）和吡格列酮（PIO组）,后用吡格列酮对PIO组大鼠进行干预治疗。8周后检测血糖水平、尿生化结果、肾脏组织病理的改变情况,同时检测尿MCP 1指标的变化。结果：与NC组比较,DM组和PIO组第8周空腹血糖及糖化血红蛋白水平均明显升高,但DM组、PIO组间差异无统计学意义（P＜0.05）;第8周DM组、PIO组尿白蛋白/尿肌酐(urinary albumin／creatinine ratio,ACR)、尿视黄醇结合蛋白(urinary retinol binding protein,URBP)、尿MCP 1(urinary monocyte chemoattractant protein 1,UMCP 1)和肾脏肥大指数均高于NC组,PIO组4项指标较DM组明显降低,且UMCP 1与ACR,URBP及肾脏肥大指数呈正相关;病理显示PIO组大鼠肾小球病变程度均较DM组明显减轻,MCP 1表达减少。结论：吡格列酮对2型糖尿病大鼠肾脏有明显的保护作用,这种保护作用是独立于降糖作用之外的。其机制可能与其抑制肾组织MCP 1表达及其排泄有关。     

α_1-肾上腺素受体抗体介导对糖尿病大鼠肾小管转化生长因子-β_1表达的影响

目的:观察α1-肾上腺素受体抗体(简称α1-受体抗体)介导的糖尿病大鼠对肾小管转化生长因子-β1(TGF-β1)表达的影响,探讨其在肾小管间质病变发生发展中的作用。方法:Wistar大鼠64只,分为对照组和糖尿病组。对照组和糖尿病组又分为无介导组与抗α1-受体抗体介导组。用链脲佐菌素复制糖尿病模型。葡萄糖氧化酶法测定血糖,放射免疫法测定尿白蛋白,免疫组化法检测肾小管基质TGF-β1的表达。结果:成功构建糖尿病大鼠模型,α1-受体抗体介导的对照组和糖尿病组肾皮质远端小管均可见TGF-β1表达,且糖尿病组明显高于对照组(P<0.01)。结论:TGF-β1在α1-受体抗体介导大鼠表达增加,即TGF-β1的表达与自身免疫有关。     

Role of neutrophil proteinase 3 and mast cell chymase in chemerin proteolytic regulation

Chemerin is a potent chemotactic factor that was identified recently as the ligand of ChemR23, a G protein-coupled receptor expressed by mononuclear phagocytes, dendritic cells (DCs), and NK cells. Chemerin is synthesized as a secreted precursor, prochemerin, which is poorly active on ChemR23. However, prochemerin can be converted rapidly into a full ChemR23 agonist by proteolytic removal of a carboxy-terminal peptide. This maturation step is mediated by the neutrophil-derived serine proteases elastase and cathepsin G. In the present work, we have investigated proteolytic events that negatively control chemerin activity. We demonstrate here that neutrophil-derived proteinase 3 (PR3) and mast cell (MC) chymase are involved in the generation of specific chemerin variants, which are inactive, as they do not induce calcium release or DC chemotaxis. Mass spectrometry analysis showed that PR3 specifically converts prochemerin into a chemerin form, lacking the last eight carboxy-terminal amino acids, and is inactive on ChemR23. Whereas PR3 had no effect on bioactive chemerin, MC chymase was shown to abolish chemerin activity by the removal of additional amino acids from its C-terminus. This effect was shown to be specific to bioactive chemerin (chemerin-157 and to a lesser extent, chemerin-156), as MC chymase does not use prochemerin as a substrate. These mechanisms, leading to the production of inactive variants of chemerin, starting from the precursor or the active variants, highlight the complex interplay of proteases regulating the bioactivity of this novel mediator during early innate immune responses.     

Prolonged Administration Enhances the Renoprotective Effect of Pentoxifylline via Anti-Inflammatory Activity in Streptozotocin-Induced Diabetic Nephropathy

The beneficial effects of pentoxifylline (PTX), which has an anti-inflammatory and renoprotective effect in diabetic nephropathy, are not completely understood. This study investigates whether prolonged administration of PTX (40 mg/kg, per oral) is effective in streptozotocin-induced diabetic nephropathy. The amount of urinary protein was higher in the diabetic rats than in the control rats. The amount remained unchanged after 4 weeks and decreased after 8 weeks of PTX treatment. Accumulation of monocyte chemoattractant peptide-1 (MCP-1) and mouse monoclonal anti-monocyte/macrophage antibody (ED-1) positive cells was higher in untreated diabetic rats than in the control rats. PTX administration ameliorated the urinary MCP-1 excretion and interstitial infiltration of ED-1 positive cells at 4 weeks. Further, in diabetic rats, administration of PTX for 4 weeks inhibited the renal inflammatory reaction, and when administration for 8 weeks, it prevented proteinuria. These findings support the hypothesis that prolonged administration enhances the protective effects of PTX.     

氯沙坦钾对2型糖尿病肾病大鼠肾脏TGF-β1、CD68和MCP-1 表达的影响

目的: 探讨氯沙坦钾对2型糖尿病肾病大鼠转化生长因子β₁ (transforming growth factor beta 1, TGF-β₁)、CD68(巨噬细胞标记物)和单核细胞趋化蛋白-1(monocyte chemoattractant protein-1,MCP-1)表达的影响,进一步说明氯沙坦钾对2型糖尿病大鼠肾脏的保护作用。方法: 雄性SD大鼠30只,按随机数字表法分为正常对照组、模型组和治疗组,每组10只。15周后, 观测肾组织形态学、肾功能和24 h尿蛋白定量等指标的变化, 用免疫组化法检测肾脏TGF-β₁、CD68和MCP-1表达水平的变化。结果: (1)与正常对照组相比,模型组及治疗组大鼠体重均降低,血糖、甘油三酯、胆固醇及MCP-1、CD68、TGF-β₁的阳性细胞数升高,模型组24 h尿蛋白和肌酐升高;(2)与模型组相比,治疗组血肌酐、24 h尿蛋白、甘油三酯及MCP-1、CD68、TGF-β₁的阳性细胞数明显降低。结论: 在2型糖尿病肾病大鼠中氯沙坦钾可以通过减少肾组织MCP-1表达,阻止巨噬细胞的浸润,下调TGF-β₁表达,对糖尿病肾病病变起到保护作用。     

抑制miR-200c表达对糖尿病肾病大鼠肾组织的保护作用及机制研究

目的　探讨抑制miR-200c表达对糖尿病肾病（diabetic nephropathy,DN）SD大鼠肾的保护作用及机制。 方法　采用高糖高脂饮食联合链脲佐菌素（streptozotocin,STZ）腹腔注射诱导建立SD大鼠DN模型,将造模成功的30只DN大鼠随机分为模型组和观察组,每组15只,同时取15只正常健康的SD大鼠作为对照组,造模成功后每7 d给予观察组大鼠尾静脉注射antagomir-200c（30 mg/kg）,模型组和对照组给予尾静脉注射等量的生理盐水。8周后,检测大鼠血清肌酐（Cr）、尿素氮（BUN）和24 h尿蛋白定量水平,实时荧光定量PCR（qRT-PCR）检测肾组织中miR-200c的表达,HE染色观察肾组织病理学变化,活性氧簇（ROS）和丙二醛（MDA）试剂盒检测肾组织中ROS和MDA水平,Western blot检测肾组织中转化生长因子-β1（TGF-β1）、纤连蛋白（fibronectin）的水平。 结果　与对照组比较,模型组大鼠肾组织miR-200c表达、血清中BUN、Cr水平、24 h尿蛋白定量、肾间质损伤评分、ROS、MDA水平及TGF-β1、fibronectin蛋白表达均升高（P<0.05）。与模型组比较,观察组大鼠以上指标均降低（P<0.05）。 结论　miR-200c在STZ诱导的DN大鼠肾组织中表达升高,抑制miR-200c能够对DN大鼠的肾起到一定保护作用,可能与降低肾组织的氧化应激水平和对TGF-β1信号通路的抑制有关。     

色素上皮衍生因子和血管内皮生长因子在糖尿病大鼠肾脏的不平衡表达

目的检测色素上皮衍生因子（PEDF）和血管内皮生长因子（VEGF）在糖尿病大鼠肾脏的表达，探讨其在糖尿病肾病（DN）发生发展中的作用。方法40只雄性Wistar大鼠随机分为：正常对照组（NC）、糖尿病模型组（DM）。4、8周末，检测血糖、糖化血红蛋白、肾重指数、尿白蛋白排泄率，免疫组织化学法检测肾脏PEDF、VEGF的表达。结果4、8周末，DM组大鼠肾脏PEDF的表达较NC组明显减少（P〈0．01）；VEGF的表达较NC组明显增多（P〈0．01）；肾脏PEDF的表达与VEGF明显负相关（r=-0．823，P〈0．01）。结论PEDF和VEGF在肾脏的不平衡表达可能参与了DN的发病。     

神经型一氧化氮合酶在1型糖尿病大鼠肾皮质中的表达

目的观察1型糖尿病大鼠肾皮质内神经型一氧化氮合酶(nNOS)的表达变化。方法采用一次性腹腔注射大量链脲佐菌素(STZ)的方法建立1型糖尿病大鼠模型。分别在成模后的第1,2,4周3个时间点处死动物,采用亚硝酸还原酶法检测一氧化氮(NO)的含量;采用免组织化学染色法观察nNOS在肾皮质的表达;采用Western blot方法测定nNOS在肾皮质含量的变化。结果1周病程时糖尿病模型组大鼠肾皮质NO表达水平低于对照组(P<0.05),2周病程时高于对照组(P<0.05),4周病程时显著高于对照组(P<0.01)。nNOS在肾皮质中的表达部位主要在致密斑,在肾小管中也有少量的表达。糖尿病模型组大鼠肾皮质nNOS含量在1周病程时低于正常对照组,2周病程时与正常对照组无显著性差异,4周病程时高于正常对照组。结论在1型糖尿病大鼠肾脏病变的早期,肾皮质内NO的减少主要是由于nNOS合成减少造成的。     

Urinary cystatin C as a biomarker for diabetic nephropathy and its immunohistochemical localization in kidney in Zucker diabetic fatty (ZDF) rats

Cystatin C, a cysteine protease inhibitor, is a novel biomarker of renal damage. In the present study, we examined the usefulness of urinary cystatin C for the detection of diabetic nephropathy in Zucker diabetic fatty (ZDF) rats compared to other biomarkers (β2-microglobulin, calbindin, clusterin, epidermal growth factor (EGF), alpha-glutathione S-transferase (GST-α), mu-glutathione S-transferase (GST-μ), kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), osteopontin, tissue inhibitor of metalloprotease-1 (TIMP-1), and vascular endothelial growth factor (VEGF). Urinary levels of cystatin C were increased in ZDF rats where renal damage was not histopathologically observed, and then further increased with the progression of renal damage, demonstrating the usefulness of early detection and accurate assessment of diabetic nephropathy. Urinary β2-microglobulin, clusterin, GST-μ, KIM-1, and osteopontin had the potency to detect renal damage in ZDF rats as well as cystatin C.We also investigated immunohistochemical localization of cystatin C in the kidney according to progressive renal damage. Cystatin C expression was mainly observed in the proximal renal tubule in ZDF rats, and hardly changed with progression of nephropathy. When renal damage was remarkable, cystatin C expression was also observed in the tubular lumen of the cortex and medulla, which was considered to be characteristic of renal damage in diabetic nephropathy.In conclusion, urinary cystatin C, β2-microglobulin, clusterin, GST-μ, KIM-1, and osteopontin could be useful biomarkers of diabetic nephropathy in ZDF rats. Immunohistochemical cystatin C expression in the proximal renal tubule was hardly changed by the progression of diabetic nephropathy, but it was newly observed in the tubular lumen when renal damage was remarkable in ZDF rats.