缬沙坦抑制高糖培养的大鼠肾小球系膜细胞细胞外基质及CTGF的表达

目的　探讨高糖状态下体外培养的肾小球系膜细胞中结缔组织生长因子（CTGF）的表达以及缬沙坦的影响。方法 体外培养大鼠系膜细胞,分别给予高糖和缬沙坦干预,采用Western blot检测CTGF、p38丝裂原活化蛋白激酶 （p38 MAPK）、cAMP反应元件结合蛋白1（CREB1）及各自磷酸化蛋白的表达,RT-PCR检测CTGF mRNA和纤维黏连蛋白（FN）mRNA的表达。放免法测定细胞上清液中层黏连蛋白(LN)和IV型胶原的含量。结果 与低糖组相比,高糖组系膜细胞CTGF、p-p38 MAPK、p-CREB1表达明显上调,CTGF mRNA和FN mRNA表达增加,细胞上清中LN和IV型胶原含量增加。缬沙坦组CTGF、p-p38 MAPK、p-CREB1的表达明显下调,CTGF mRNA和FN mRNA表达降低, LN和IV型胶原的含量减少。 结论　缬沙坦抑制高糖状态系膜细胞CTGF表达 和细胞外基质的分泌可能部分是通过影响p38 MAPK及其下游核因子CREB1的激活而实现。     

霉酚酸酯对高糖培养下人肾小球系膜细胞MCP-1和FN表达的影响

目的:探讨高糖以及霉酚酸酯(MMF)对人肾小球系膜细胞(HMCs)单核细胞趋化蛋白-1(MCP-1)和纤维连接蛋白(FN)表达的影响。方法:将培养的HMCs分为正常对照组(5 mmol/L葡萄糖);高糖组(30 mmol/L葡萄糖);甘露醇渗透压对照组(5 mmol/L葡萄糖+25 mmol/L甘露醇);高糖+MMF-10组(30 mmol/L葡萄糖+10μg/mL MMF);高糖+MMF-100组(30 mmol/L葡萄糖+100μg/mL MMF),采用RT-PCR检测每组不同时间点(24、48、72 h)MCP-1 mRNA的表达,ELISA法检测培养上清液MCP-1及FN蛋白的表达。结果:高糖组HMCs MCP-1 mRNA、蛋白的表达及FN的分泌较正常对照组显著增加(P<0.01),且48 h表达最高;不同浓度的MMF均能下调MCP-1 mRNA、蛋白及FN的表达(P<0.01);不同浓度的MMF对MCP-1 mRNA、蛋白的表达及FN分泌的抑制程度不同,呈时间剂量依赖性(P<0.05)。结论:MMF可以阻抑MCP-1的表达及FN的分泌,可能对延缓肾小球硬化及间质纤维化有一定作用。     

AMPK在高糖诱导大鼠肾小球系膜细胞Ⅳ型胶原过度表达中的作用

目的 观察高糖环境下大鼠肾小球系膜细胞Ⅳ型胶原蛋白表达水平的变化,以及这种变化与AMP活化蛋白激酶（AMPK）的关系。方法 实验分4组：对照组（糖浓度5.6 mmol/L）,高糖组（22.0mmol/L）,低浓度5-氨基-4-甲酰胺咪唑核糖核苷酸（AICAR）组（0.5mmol/L AICAR+高糖）,高浓度AICAR组（1.0mmol/L AICAR+高糖）。孵育24h后,用RT-PCR法测定AMPKα1 mRNA水平,用Western blot法分别测定总AMPKα蛋白（AMPK）、磷酸化AMPKα蛋白（p-AMPK）和Ⅳ型胶原蛋白α5（COL4α5）亚单位的表达水平。结果 高糖组AMPKα1 mRNA水平低于对照组（p＜0.01）;高糖组总AMPKα蛋白和磷酸化AMPKα蛋白表达水平均低于对照组（p＜0.01）,高糖组COL4α5亚单位表达水平高于对照组（p＜0.01）;AMPK激活剂AICAR可在不同程度上纠正上述变化。结论 高糖环境下大鼠肾小球系膜细胞Ⅳ型胶原蛋白表达水平上调,这可能与AMPK表达下调及其活性降低有关。     

细胞外基质在人系膜增生性肾小球肾炎病变中的变化

肾小球细胞外基质（尤其系膜基质）的过量聚积是肾小球硬化的主要变化之一。我们应用免疫酶标技术及计算机图像分析系统，检测了系膜增生性肾小球肾炎病变过程中细胞外基质的变化。结果表明：增生扩张的系膜基质中含有Ⅳ型胶原，层粘连蛋白等多种正常肾小球细胞外基质成分，并随病变进展明显增加。Ⅲ型胶原在中，重度系膜增生性肾小球肾炎时也出现于增多的系膜基质中，说明正常时不存在于肾小球的间质胶原在肾小球过程中也起重要作用     

高水平胰岛素对大鼠系膜细胞NF-κB活化及细胞外基质合成的影响

探讨高水平胰岛素对系膜细胞NF-κB p65活化及细胞外基质合成的影响。用高水平的胰岛素刺激系膜细胞后,用免疫组化染色观察系膜细胞NF-κB p65活化,放免法测定系膜细胞培养上清液中Ⅳ型胶原及层粘蛋白(LN)水平。并以无胰岛素刺激为正常对照组。结果显示胰岛素刺激后,系膜细胞内NF-κB p65核移位阳性率(PR)、平均光密度(ALD)以及上清液中Ⅳ型胶原、LN在一定浓度范围内呈剂量和时间依赖性增加,表明胰岛素可促进系膜细胞的NF-κB p65活化和细胞外基质的合成。     

醛固酮对肾小球系膜细胞合成分泌纤维连接蛋白和TGF-β1表达的影响

目的：研究醛固酮（ALD）及其受体拮抗剂螺内酯（SPI）对大鼠肾小球系膜细胞合成分泌纤维连接蛋白（FN），以及对转化生长因子B1（TGF-β1）基因表达的影响。方法：（1）以不同浓度的ALD（10^-11、10^-9、10^-7mol／L）及／或10^-7mol／L SPI刺激肾小球系膜细胞48h后，用ELISA法测定培养上清中FN的浓度。用半定量RT-PCR法检测该细胞中FNmRNA和TGF-β1mRNA的表达。（2）以10^-9mol／L的ALD刺激系膜细胞不同时间（24、48、72h）后，分别用上述方法测定培养上清中FN的浓度和细胞中FNmRNA和TGF-β1mRNA的表达。结果：（1）ELISA的结果显示，ALD可促进系膜细胞合成分泌FN，且呈剂量和时间依赖性，SPI能拮抗ALD的作用。（2）半定量RT-PCR的结果显示，ALD可促进系膜细胞FNmRNA和TGF-β1mRNA的表达，也呈剂量和时间依赖性，SPI也能拮抗ALD的作用。结论：ALD在蛋白和基因水平上均可促进大鼠肾小球系膜细胞合成分泌FN，及TGF-β1mRNA的表达，SPI能拮抗ALD的作用，具有一定的肾脏保护作用，从而有益于延缓肾小球硬化的进展。     

大黄酸及大黄素诱导高糖大鼠肾小球系膜细胞的凋亡

背景：课题组前期实验证实中药复方消可宁能有效防治早期糖尿病肾病。 目的：比较大黄酸与大黄素对高糖培养的大鼠肾小球系膜细胞凋亡的影响程度。 方法：分别用不同浓度20,40,80 µmol/L的大黄酸和大黄素刺激高糖培养的肾小球系膜细胞,苏木精-伊红染色观察凋亡细胞形态,DAPI荧光染色观察细胞核凋亡情况,流式细胞仪观察细胞凋亡率。 结果与结论：苏木精-伊红染色及DAPI染色结果显示大黄酸对髙糖培养的肾小球系膜细胞凋亡的影响程度强于大黄素的影响程度。细胞凋亡率的对比显示大黄酸对髙糖培养的肾小球系膜细胞的早期凋亡率与晚期凋亡率均强于大黄素。说明低中高浓度的大黄酸、大黄素均可诱导肾小球系膜细胞凋亡,但大黄酸的药效强于大黄素。     

rhIL-1受体拮抗剂对大鼠肾小球系膜细胞增殖和合成细胞外基质-胶原的影响

采用肾小球系膜细胞(GMC)培养、~3H-TdR掺入及羟脯氨酸测定的方法,首次观察了重组人白细胞介素-1受体拮抗剂(rhIL-1Ra)对白细胞介素1β(IL-1β)诱导的大鼠GMC增殖和合成细胞外基质-胶原的影响。结果表明:rhIL-1Ra能拮抗hIL-1β诱导的GMC的增殖和胶原的合成;其拮抗增殖的剂量是rhIL-1β的2～50倍,拮抗胶原合成者为rhIL-1β的25～50倍。提示:rhIL-1Ra有望用于治疗由IL-1参与、介导的以系膜细胞增殖和系膜基质扩大为主要病理改变的肾小球肾炎。     

依维莫司对高糖诱导肾小球系膜细胞凋亡的保护作用

目的:观察依维莫司对高糖诱导肾小球系膜细胞(HBZY-1)凋亡的保护作用,并探讨其意义。方法:将培养HBZY-1细胞按不同葡萄糖和依维莫司浓度分组处理72h后,用磺酰罗丹明B法测量细胞OD值,计算各组细胞存活率,用Annexin V和PI双标法检测各组细胞凋亡率。结果:30mM葡萄糖处理的细胞存活率明显降低,凋亡率明显增加(均P<0.05)。不同浓度依维莫司均能提高细胞存活率(均P<0.05),其中以200ng/ml依维莫司效果最好(P<0.05);200ng/ml依维莫司具有明显抗HBZY-1细胞凋亡作用。结论:依维莫司对高糖诱导HBZY-1细胞凋亡具有保护作用,从而为其治疗糖尿病肾病提供新的研究方向。     

高糖培养人肾小球系膜细胞对TGF-β1、FN、Smad7表达的影响

目的:通过观察高糖对人肾小球系膜细胞(HMCs)转化生长因子-β1(TGF-β1)、纤维连接蛋白(FN)、Smad7表达的影响,探讨糖尿病肾病(DN)的发病机制。方法:将HMCs于高糖(30mmol/L)环境培养不同时间后,采用RT-PCR方法检测TGF-β1、FN、Smad7 mRNA表达,Western blotting检测Smad7蛋白的表达,采用ELISA检测TGF-β1、FN蛋白水平,同时以低糖培养作为对照组。结果:高糖培养24h、48h、72h后,TGF-β1 mRNA及蛋白的表达均较低糖培养对照组增加,在48h时达到高峰;FN mRNA及蛋白的表达亦较对照组增加,且呈时间依赖性;而Smad7 mRNA及蛋白表达下降。结论:TGF-β1/Smad信号转导途径负反馈调节Smad7蛋白的表达减少,可能是DN发病过程中的重要环节之一。     

L-精氨酸对人肾系膜细胞胞外基质产生的影响

目的:探讨L-精氨酸(L-arg)对人肾系膜细胞胞外基质产生的影响及其作用机制。方法:运用放射免疫分析技术及羟-脯氨酸比色法分别检测L-arg作用后系膜细胞上清液中Ⅲ型前胶原与总胶原含量;运用RT-PCR技术检测L-arg对人肾系膜细胞Ⅳ型胶原基因表达的影响。结果:L-arg抑制Ⅲ型前胶原产生,抑制总胶原分泌,并抑制Ⅳ型胶原基因表达。结论:L-arg抑制人肾系膜细胞胞外基质产生,并可能与抑制胶原成分的基因转录有关。     

The inhibitory effect of siRNAs on the high glucose-induced overexpression of TGF-beta1 in mesangial cells

Diabetic nephropathy is characterized by an expansion of the glomerular mesangium, caused by mesangial cell proliferation and an excessive accumulation of extracellar matrix (ECM) proteins, which eventually leading to glomerulosclerosis. TGF-beta1 was found to play an important role in the accumulation of ECM in the kidney. In this study, TGF-beta1 RNA interference was used as an effective therapeutic strategy. The inhibitory effect of TGF-beta1 small interfering RNAs (siRNAs) on the high glucose-induced overexpression of TGF-beta1 in rat mesangial ceys (RMCs). A high levels of glucose induces TGF-beta1 mRNA and protein, and TGF-beta1 siRNAs reduce the ability of high glucose to stimulate their expression. We also examined the inhibitory effect of TGF-beta1 siRNAs on the expression of plasminogen activator inhibitor (PAI)-1 and Collagen Type I which are down-regulators of TGF-beta1. The expression of TGF-beta1, PAI-1 and Collagen Type I was increased in RMCs that were stimulated by 30 mM glucose. TGF-beta1 siRNAs reduces high glucose-induced TGF-beta1, PAI-1, and Collagen Type I mRNA and protein expression in a dose-dependent manner. In conclusion, the present study demonstrates that TGF-beta1 siRNAs effectively inhibits TGF-beta1 mRNA and protein expression in RMCs. These suggest that TGF-beta1 siRNAs through RNAi may be a useful tool for developing new therapeutic applications for the treatment of diabetic nephropathy.     

Ex vivo transfer of the decorin gene into rat glomerulus via a mesangial cell vector suppressed extracellular matrix accumulation in experimental glomerulonephritis

The activation of transforming growth factor-beta (TGF-beta) is known to be one of the major causes of glomerulosclerosis. Decorin (DCN) is a natural inhibitor of TGF. The purpose of this study was to assess the feasibility of transferring the DCN gene to antithymocyte serum (ATS) glomerulonephritis glomeruli via a mesangial cell vector to treat glomerulonephritis fibrosis. For this process, the recombinant eukaryotic expression plasmid pcDNA3.1A-DCN was constructed and transfected into mesangial cell. The DCN-positive cloned cells were transferred to rat antithymocyte serum glomeruli by a left renal artery injection. Using immunohistochemical staining, approximately 37-60% (48.6% +/- 11.34%; mean +/- SE, n = 8) of the glomeruli were BrdU-positive in the injected-side kidney. DCN proteins were observed in the cytoplast beginning 12 h after injection. TGF-beta1 expression in the injected side glomeruli decreased significantly at day 4 (P < 0.05), compared with that in the uninjected-side kidney. The expression leaves of fibronectin and collagen IV decreased significantly at days 1-2 (P < 0.01) and day 4 (fibronectin, P < 0.01; collagen IV, P < 0.05). These results suggest that the use of DCN can decrease antithymocyte serum glomerulonephritis extracellular matrix (ECM) ingredients and that such use offers a favorable experimental basis for gene therapy for kidney disease.     

Behavior of rat mesangial cells cultured within extracellular matrix

Rat mesangial cells were cultured within hydrated laminin-rich gels prepared from the Engelbreth-Holm-Swarm mouse tumor (E gel) or within type I collagen gels (C gel) to examine the effects of extracellular matrix on cell morphology, growth and proteoglycan (PG) synthesis. Rat dermal fibroblasts were also cultured under the same conditions for comparison with mesangial cells. Mesangial cells extended an array of cell processes, developing an arborized shape within E gel, whereas they were elongate and bipolar within C gel. Conversely, fibroblasts adopted a bipolar elongate morphology in both E gel and C gel. The growth rate of cultured cells was determined by autoradiography using [3H]thymidine. The growth rate of 3H-labeled mesangial cells was higher than or about the same as that of labeled fibroblasts both on glass and within C gel, whereas within E gel the growth rate of mesangial cells was significantly lower than that of fibroblasts. In both mesangial cells and fibroblasts, there was no significant difference in the amounts of [35S]sulfate incorporated into macromolecules between cultures within E gel and C gel. However, gel chromatography on Sepharose CL-6B showed changes in the hydrodynamic size of newly synthesized PGs and glycosaminoglycan chains. The 35S-labeled PGs and glycosaminoglycan chains synthesized by mesangial cells cultured within E gel were smaller than those of cells cultured within C gel. In contrast, the PGs and glycosaminoglycan chains synthesized by fibroblasts within E gel were larger than those synthesized within C gel. These findings indicate that the extracellular matrix is important in regulating the morphology, growth, and PG synthesis of mesangial cells.     

丹酚酸B对高糖诱导的肾小球系膜细胞表型转化及细胞外基质分泌的影响

目的:研究丹酚酸对高糖诱导的肾小球系膜细胞表型转化及细胞外基质分泌的影响及其机制。方法:培养人肾小球系膜细胞(HGMCs),随机分为正常对照组、高糖组及高糖+丹酚酸B高、中、低剂量组,高糖组和丹酚酸B各组用含高浓度(33.3 mmol/L)葡萄糖的培养基培养72 h,丹酚酸B各组同时加人相应浓度丹酚酸B共同孵育。Western blot法检测α-平滑肌肌动蛋白(α-SMA)的表达水平,ELISA法检测细胞Ⅰ型胶原(ColⅠ)、Ⅲ型胶原(ColⅢ)、纤维连接蛋白(FN)和层粘连蛋白(LN)的分泌水平,Western blot法检测转化生长因子β1(TGF-β1)的表达及Smad2和p38丝裂原活化蛋白激酶(MAPK)的磷酸化水平。结果:高糖孵育72 h后,肾小球系膜细胞α-SMA的蛋白表达水平明显升高,ColⅠ、ColⅢ、FN及LN蛋白的分泌水平显著增加(P 0.01),TGF-β1的表达及Smad2、p38 MAPK的磷酸化水平也明显升高(P 0.01);与丹酚酸B共同孵育可明显降低α-SMA蛋白的表达水平,ColⅠ、ColⅢ、FN和LN的分泌明显减少,TGF-β1的表达及Smad2、p38 MAPK的磷酸化水平显著下降(P 0.01或P 0.05)。结论:丹酚酸B可明显抑制高糖诱导的肾小球系膜细胞表型转化,减少ColⅠ和ColⅢ等细胞外基质分泌,其机制与抑制TGF-β1/Smad信号通路及p38 MAPK活化有关。     

转染结缔组织生长因子基因的大鼠肾系膜细胞纤连蛋白和Ⅳ型胶原表达的改变

目的观察大鼠肾系膜细胞（MsC）转染结缔组织生长因子（CTGF）基因转染阳性细胞克隆中纤连蛋白（FN）和Ⅳ型胶原（ColⅣ）表达的改变,探讨CTGF在肾小球硬化发生中的作用。方法经脂质体介导将含有CTGF的重组表达质粒转染至大鼠MsC,用G418筛选及Western blot和半定量逆转录聚合酶链反应作鉴定;检测阳性克隆FN、ColⅣ蛋白及其mRNA表达的改变。结果成功建立高表达CTGF的阳性MsC克隆（MCT-1,2）,并证实其与对照组相比,阳性MsC克隆FN、ColⅣ的表达均有上调,其FN蛋白及其mRNA表达分别增高2．9倍和3．2倍,ColⅣ蛋白和mRNA表达分别增高为2．4倍和3．8倍。结论CTGF可促进MsC的FN、ColⅣ的表达。表明其在肾小球硬化发生中起促进作用。     

Formation of extracellular matrix by cultured rat mesangial cells.

Formation of extracellular matrix (ECM) by mesangial cells (MCs) contributes to progressive glomerulosclerosis. The authors investigated the production and distribution of ECM constituents by cultured rat MCs, using immunocytochemistry and immunoelectron microscopy. Staining for all ECM constituents increased after serum feeding. Localization was strictly intracellular until confluency, when extracellular deposition of collagen IV and laminin appeared, followed by fibronectin and collagen III. In parallel, the intracellular staining for these proteins diminished markedly. Neither extracellular deposition nor intracellular loss was observed for collagen I and thrombospondin. On surfaces coated with collagen IV or laminin, extracellular deposition of ECM constituents clearly preceded confluency. These results indicate that synthesis of ECM constituents parallels MC growth, and that extracellular deposition of ECM occurs at cell-cell contact. Collagen IV or laminin secreted by MCs in the substratum accelerates production and facilitates secretion of other ECM constituents in an autocrine fashion.     

Evolution of Xenopus endodermal cells cultured on different extracellular matrix components. Identification of primordial germ cells

Summary Plated on untreated glass substrate, Xenopus endodermal cells are unable to undergo any morphological or cytological differentiation.Cultured on artificial substrates prepared with components of the extracellular matrix, the endodermal cell behavior is entirely different.To identify the primordial germ cells (PGC), we use three coated substrate types: fibronectin, collagen and collagen plus fibronectin. These substrates allow us to distinguish three cell types shortly after explantation.Using fibronectin-coated substrate, most of the cells, after attachment and spreading, form cellular islets which tend to fuse, leading to the formation of a polyhedric cell monolayer. Such fusing is notably reduced on composite substrate (Coll+FN) or on collagen substrate only. Thus it is possible to distinguish the special morphological features exhibited by the rest of the cells. Some of them retain the aspect of endodermal gastrula cells in vitro. Others, elongated or spindle-shaped, possess the characteristics of PGC. Nevertheless, the identification and sampling of the presumed germ cells is easier on COLL+FN-coated substrate. The morphological and cytological characteristics of the elongated cells are similar to those obseryed during PGC migration through the endodermal mass.According to these results, there is little doubt that these elongated cells are primordial germ cells.Abbreviations PGC primordial germ cells - cAMP cyclic adenosine monophosphate - FN fibronectin - COLL collagen - EDTA disodium ethylene diamine tetra acetic acid - CIG cold insoluble globulin - SEM scanning electron microscopy - ECM extracellular material     

Chondrocyte phenotypes on different extracellular matrix monolayers

Chondrocytes undergo a process of dedifferentiation in monolayer culture that is characterized by a transition to a fibroblast-like phenotype. This behavioral change poses a challenge for tissue-engineered cartilage constructs, as approaches using autologous cells require expansion in vitro. Because chondrocytes express a variety of integrin receptors specific to different adhesive proteins, we hypothesized that chondrocytes expanded on various underlying protein monolayers would have different phenotypic responses. Bovine articular chondrocytes were cultured for up to 2 weeks on tissue culture plastic, fibronectin, collagen type I or collagen type II substrate in the presence or absence of ascorbate. Contrary to our hypothesis, the extracellular matrix protein substrates used in this study did not significantly alter the changes in chondrocyte morphology, gene expression, matrix formation, or cytoskeletal organization. Cells on all substrates assembled equivalent matrices, which may have subsequently regulated cell behavior. In cultures with ascorbate, populations of round and spread cells emerged after 1 week, with round cells expressing collagen type II and the differentiated phenotype and spread cells dedifferentiating. In cultures without ascorbate, chondrocytes rapidly adhered and spread onto organized fibronectin matrices via the ₅β₁ integrin, which has been associated with survival and proliferation of chondrocytes in vitro. These findings indicate that expanding chondrocytes on protein monolayers may not be an effective solution to preventing dedifferentiation and improving autologous chondrocyte transplantation.     

Expression of extracellular matrix proteins in the fetal rat gastric mucosa

At gestational day 16 the epithelium of the rat stomach consists of a stratified layer of undifferentiated cells, and two days later glandular structures appear. The present study was carried out to identify extracellular matrix proteins that could be involved in the epithelial cell proliferation and differentiation processes that occur in the fetal rat stomach during this period. For comparative purposes the expression of the same components in the adult gastric mucosa was examined. Pregnant Sprague-Dawley rats received an intraperitoneal injection of 5-bromo-2’-deoxyuridine to label proliferating cells. One, 3.5, or 6 h post-injection the stomachs were excised and immediately frozen. The specimens were sectioned and stained with hematoxylin and eosin or for 5-bromo-2’-deoxyuridine, cytokeratin no. 8, H,K-ATPase, and the extracellular matrix proteins fibronectin, laminin, and collagens type I and IV. A stratified layer of proliferating cells was observed in the epithelium of the fetal stomachs, while in adult stomachs proliferating cells were detected in the isthmus/neck region of the glands. Cytokeratin, an epithelial cell marker, was sparse at gestational day 16 but abundant both at gestational day 18 and in the isthmus/neck region of gastric glands of the adult stomach. The parietal cell marker H,K-ATPase could not be detected in the fetal stomachs during this period. Fibronectin was observed in the stroma of both fetal and adult stomachs. Collagen type I could only be detected in the stroma close to the oesophagus at gestational day 16. Two days later, collagen type I was abundant in the lamina propria, the submucosa and in the serosa of the fetal stomachs. In adult tissue collagen type I was detected in the surface epithelium, the submucosa and in the serosa of the stomach. Collagen type IV and laminin were expressed in the lamina propria, the basement membranes around blood vessels, muscle cells, and nerve bundles, as well as in the serosa of both 16- and 18-day-old fetal and adult rat stomachs. In conclusion, a high cell proliferation rate was observed in the epithelium at both gestational days 16 and 18. The increased expression of cytokeratin observed during this period indicates that the epithelial character of the embryonic cells becomes more distinct, while the remarkable change in the expression of collagen type I might reflect an important role of collagen type I in the development of the gastric epithelium. Accepted: 2 September 1999