肾素-血管紧张素系统在糖尿病肾病肾脏足细胞损伤中的作用

糖尿病肾病(diabetic kidney disease,DKD)作为诱发终末期肾脏病(end-stage renal disease,ESRD)的主要原因,至今其病理机制仍不十分清楚.DKD病程中蛋白尿持续增多并伴随肾素-血管紧张素系统(renin-angiotensin system,RAS)过度激活.阻断RAS能改善蛋白尿,有良好的临床肾脏保护作用.足细胞表达RAS的各成员,作为肾小球滤过的最后屏障,其损伤与蛋白尿的发生关系密切.本文就RAS与足细胞损伤在DKD病理中作用作一简单综述.     

肾素 - 血管紧张素 - 醛固酮系统阻滞的研究进展

肾素-血管紧张素-醛固酮系统起初被认为是较简单的神经体液调节机制之一。但是,这一想法随着RAAS阻滞剂:肾素阻滞剂、血管紧张素转换酶抑制剂(ACEI)、AT1受体拮抗剂及盐皮质激素受体拮抗剂的深入研究而受到挑战。因此,RAAS的组成、以上药物发挥作用的具体通路及副作用均得到重新定义。在RAAS阻滞剂的应用过程中,机体肾素水平升高,并刺激肾素原受体(即无活性的肾素前体,PRR),进而对机体造成不良影响。同理,在AT1受体拮抗剂的应用过程中,血浆血管紧张素II的水平升高,并与2型血管紧张素II(AT2)受体结合,进而对机体产生有利作用。此外,随着ACEI及ARB的应用,血管紧张素1-7水平升高,其与Mas受体结合,发挥心脏及肾脏保护的作用,还可通过刺激干细胞发挥组织修复作用。     

肾脏中肾素-血管紧张素系统的生理和病理生理作用

肾脏中肾素-血管紧张素系统(RAS)在肾脏生理功能的调节中有重要作用.近年来,肾脏RAS的新成分及新作用机制不断被发现.转基因动物研究使肾脏血管紧张素Ⅱ(AngⅡ)在血压及水钠平衡调节中的作用进一步阐明;AngⅡ的非血流动力学作用已经确立;血管紧张素转换酶2(ACE2)及Ang 1～7对肾功能的调节作用也已得到认可.肾素/前肾素特异性受体、ACE的信号转导功能,以及AT1受体的转激活功能等,已成为肾脏生理科学研究的热点.这些研究对于人们认识肾脏局部RAS功能,探讨延缓慢性肾脏病的进展的治疗策略具有重要意义.     

不同年龄白发性高血压大鼠肾脏AT1R和AT2R的表达

目的本研究观察不同月龄自发性高血压大鼠（SHR）肾脏ALR和ALR表达,初步探讨AT1R和AT2R在高血压发生、发展过程中的可能作用。方法1月龄组（S1）、2月龄组（S2）、3月龄组（S3）、6月龄组（S6）和9月龄组（墨）雄性SHR共5组,每组各6只,各组均有相应月龄匹配的Wistar-Kyoto大鼠（WKY）作对照。采用RBP-I型大鼠血压心率测定仪测量大鼠尾动脉收缩压（SBP）;放免法测定血浆血管紧张素Ⅱ（AngⅡ）;免疫组化染色结合计算机图像分析方法测定肾脏AT1R和ALR表达水平。结果（1）SHR SBP随着月龄的增加而上升,S6后趋于稳定。（2）1个月后SHR血浆AngⅡ浓度均高于S1（P〈0.05）,而S2、S3、S6和S9之间无明显差别（P〉0.05）;1个月后SHR血浆AngⅡ浓度均高于相应配对的WKY组（P〈0.05）;而WKY各月龄组均无明显差别（P〉0.05）。（3）SHR肾脏AT1R随着月份的增加而增加（P〈0.05）,且高于相应配对的WKY组（P〈0.05）。SHR肾脏ABR随着月份的增加而降低,S6明显降低（P〈0.05）,S6和S9比较无明显差别（P〉0.05）;且均低于相应配对的WKY组（P〈0.05）。WKY各月龄组AT1R和AT2R无明显差别（P〉0.05）。结论SHR肾脏AT1R表达水平比WKY高,并随着年龄的增加而递增;AT2R表达水平比WKY低,并随着年龄的增加而降低。     

缬沙坦对人肾小球系膜细胞糖基化终产物受体表达的影响

目的：本实验探讨缬沙坦对糖基化终产物诱导的人肾小球系膜细胞氧化应激水平及糖基化终产物受体（RAGE）表达的影响。方法：体外常规培养人肾小球系膜细胞,运用糖基化修饰的牛血清白蛋白（AGE-BSA）和缬沙坦进行干预,流式细胞术检测细胞内活性氧（ROS）,RT-PCR法检测NADPH氧化酶的亚基p47^phox的mRNA表达,RT-PCR和细胞免疫化学法检测RAGE的表达量。结果：缬沙坦干预组人肾小球系膜细胞的ROS产生量、NADPH氧化酶的亚基p47^phox mRNA表达量、RAGE表达量均低于AGE-BSA组（P〈0．05）,且缬沙坦的抑制作用呈浓度和时间依赖性。结论：缬沙坦可能通过降低氧化应激水平来抑制RAGE的表达。     

血管紧张素Ⅱ2型受体基因缺失不影响肾素-血管紧张素系统

基于目前对血管紧张素Ⅱ2型受体(AT2)功能的认识,认为血管紧张素Ⅱ1型受体(AT1)和AT2受体有相互拮抗作用.依据上述论点,本研究利用AT2受体基因敲出小鼠,观察了AT2受体缺失后是否造成肾素-血管紧张素系统其它成分代偿性紊乱.结果发现,AT2受体基因缺失小鼠血浆和肾组织中血管紧张素Ⅱ的浓度以及肾组织中肾素、AT1A受体的基因表达均未发生明显改变,表明AT2受体缺失未对肾素-血管紧张素系统产生显著影响,AT2受体的功能已被代偿,但代偿途径尚有待于进一步研究.     

作为肾素-血管紧张素系统调节器和SARS病毒受体的人血管紧张素转换酶2

人血管紧张素转换酶2(ACE2)是目前已知的惟一的人血管紧张素转换酶(ACE)的同源物,是一种新型的金属羧肽酶,很多特性与ACE截然不同.ACE2在肾素-血管紧张素系统(RAS)中具有独特的作用,调节心脏功能和机体血压.最近ACE2被鉴定为SARS病毒的功能受体.ACE2已经成为目前药物研发的新靶点.对ACE2的认识才刚刚开始,有待进-步深入研究.     

高糖刺激下大鼠肾小球系膜细胞CTGF和MT1-MMP的表达

目的观察高糖刺激的大鼠肾小球系膜细胞结缔组织生长因子(CTGF)和膜型基质金属蛋白酶-1(MT1-MMP)的动态变化,探讨糖尿病肾病(DN)的发病机制。方法体外培养的大鼠HBZY-1肾小球系膜细胞分为正常糖对照组,高糖组和甘露醇高渗对照组,采用RT-PCR及Western印迹法分别检测CTGF和MT1-MMP的mRNA及蛋白的表达,用酶联免疫吸附法(ELISA)检测培养上清中IV型胶原的含量。结果与对照组相比,高糖组各时间点系膜细胞CT-GF表达明显上调,IV型胶原的分泌增加,且二者随时间持续增高;而MT1-MMP的表达则随时间呈明显下降趋势。结论高糖可诱导肾小球系膜细胞CTGF表达增加,同时抑制MT1-MMP的表达,二者可能参与DN中细胞外基质(ECM)代谢失衡过程。     

慢性阻断血管紧张素Ⅱ1型受体不能完全防止模拟失重大鼠血管的适应性结构变化

我们以前的工作提示,在模拟失重所引起的血管区域特异性适应变化中,局部肾素．血管紧张素系统（local reninangiotensin system,L-RAS）可能发挥关键调控作用。本文以losartan慢性阻断血管紧张素Ⅱ1型受体（angiotensin Ⅱtypelreceptor,AT1R）,观察模拟失重是否仍能引起血管的这种适应性改变,并检测大血管管壁L-RAS主要成分的表达是否也发生相应变化。以尾部悬吊大鼠模型模拟失重的生理影响。制作基底动脉、胫前动脉、颈总动脉和腹主动脉的HE染色切片,在光学显微镜下进行形态观测：用免疫组织化学技米测量颈总动脉和腹主动脉壁的血管紧张素原（angiotensinogen,AGT）及AT-R的表达变化。结果表明：4周模拟失重引起大鼠基底动脉中膜和颈总动脉管壁各平滑肌肌层肥厚,而胫前动脉和腹主动脉则发生萎缩性改变;给予losartan4周引起上述4种血管皆发生萎缩性变化;阻断AT1R,模拟失重仍然能引起基底动脉、颈总动脉发生相对肥厚性改变和腹主动脉萎缩加重。4周模拟失重还引起颈总动脉壁中AGT和AT1R表达上调,而腹主动脉壁及血管周围组织中AGT和AT1R表达下调;给予losartan4周仅引起腹主动脉壁中AGT和AT1R表达减少;阻断AT1R,模拟失重使腹主动脉壁AT1R表达进一步减少。结果提示,4周模拟失重引起大鼠脑、颈部与后身大、中动脉血管的形态结构改变和L-RAS主要成分表达发生上调或下调,血管L-RAS在其中可能发挥关键性调控作用;但在慢性阻断AT1R的条件下,其它调控机制仍可能在脑血管适应性调节中发挥一定作用。     

利钠肽系统与肾素-血管紧张素-醛固酮系统在心力衰竭中交互作用

慢性心力衰竭是以高发病率、高入院率及高死亡率为特征的临床综合征,也是各种心血管疾病发展的终末阶段。神经激素系统的激活在心力衰竭病理生理中起着关键作用,其以肾素-血管紧张素-醛固酮系统(RAAS)、交感神经系统(SNS)及利钠肽系统(NPs)为主要组成部分。在心衰的病理生理中,NPs与RAAS存在交互作用,其对于与心功能不全相关的血液动力学改变与组织重塑起重要的作用,并且最终可导致心衰的恶化。因此,能够同时作用于RAAS与NPs,并且能够纠正两者间调节紊乱的干预措施,对于慢性心衰的治疗将具有良好的疗效。本文将主要对RAAS、NPs及NPs与RAAS的交互作用在心衰中的病理生理作用进行综述,并展望针对NPs与RAAS的交互作用的临床应用前景。     

Expression and purification of human (pro)renin receptor in insect cells using baculovirus expression system

The renin-angiotensin (RA) system is important for the regulation of blood pressure and electrolyte balance, and renin is the rate-limiting enzyme in this system. The recent discovery of (pro)renin receptor (PRR) has reinforced the functional role of the RA system. PRR non-proteolytically activates prorenin and its role has attracted the attention of researchers towards the RA system. However, there is insufficient information on the biochemical structure and biological functioning of PRR due to the difficulty of measuring PRR expression. In this work, human PRR (hPRR) with intact transmembrane and C-terminal domain (hPRR-wTM) and PRR without this domain (hPRR-w/oTM) were expressed in insect cells using baculovirus expression system (BES). Both hPRR-wTM and hPRR-w/oTM were fused with FLAG peptide by its N-terminus. Most of the hPRR-wTM was expressed in cell fraction and hPRR-w/oTM was secreted into the culture medium. hPRR-wTM was solubilized from the membrane fraction of recombinant baculovirus-infected cells by various detergents, suggesting that hPRR-wTM might be a transmembrane protein. hPRR-wTM was purified from the solubilized fraction using anti-FLAG M2 antibody agarose. Binding of purified hPRR-wTM to renin immobilized onto sensor chips was directly proportional to the hPRR-wTM concentration. Approximately 225 μg of functional hPRR-wTM was purified from 80 ml of baculovirus-infected cell culture. Scale-up of this system will lead to mass production and crystallization of hPRR-wTM and determination of its biochemical structure and biological function.     

Expression of Fc alpha/mu receptor by human mesangial cells: a candidate receptor for immune complex deposition in IgA nephropathy.

IgA nephropathy is characterized by the deposition of IgA immune complexes in the glomerular mesangium, but the mechanisms responsible for this are not well understood. Human mesangial cells (HMCs) can bind IgA but do not express known IgA receptors. We show here that primary HMCs express mRNA for a novel receptor, the Fc alpha/mu receptor (Fcalpha/muR), and that receptor expression is upregulated by IL-1. We also detected mRNA for a novel receptor variant in HMCs that may encode a soluble form of the receptor. Fcalpha/muR was expressed in a heterologous system which showed that the receptor was approximately 58 kDa in weight and was only minimally N-glycosylated. As predicted from the characteristics of the murine homologue, the expressed human Fcalpha/muR was able to bind IgA and IgM, but not IgG. These results suggest that Fcalpha/muR may be the receptor responsible for mesangial IgA deposition in IgA nephropathy.     

Okadaic acid stimulates caspase-like activities and induces apoptosis of cultured rat mesangial cells

Glomerular mesangial cells play an important role in the development of glomerulosclerosis. Mesangial cell apoptosis has been shown to be involved in different stages of development of glomerulonephritis. The aim of the present study was to evaluate the effect of inhibition of serine/threonine phosphatases by okadaic acid, a shell fish toxin, on rat mesangial cell apoptosis and to examine the molecular mechanisms particularly the role of caspases. Okadaic acid significantly induced mesangial cell apoptosis, as measured by an increase in cytoplasmic nucleosome-associated DNA fragmentation. The induction of apoptosis was dependent on protein synthesis, because cyclohexamide, a protein synthesis inhibitor, blocked okadaic acid-induced apoptosis. In addition, okadaic acid stimulated caspase activities (as measured by caspase substrate peptide hydrolysis) in cultured rat mesangial cells at different time points. After 12 h treatment, okadaic acid caused a modest increase in caspase-8 (IETD-pNAse)(159.3 ± 6.7%) activity, while after 18 h treatment, okadaic acid caused a significant increase in caspase-3 (DEVD-pNAse)(906 ± 245%) activity. Okadaic acid-stimulated caspase-3 activity was inhibited by Z-IETD-FMK (caspase-8 inhibitor) suggesting that the caspase-3 activity is downstream of caspase-8 activity. Both caspase-3 and caspase-8 inhibitors blocked okadaic acid-stimulated apoptosis. These data suggest that inhibition of protein phosphatases by okadaic acid induces apoptosis in rat mesangial cells by activating caspase-3- and -8-like activities and that caspase-3-like activity is downstream of caspase-8-like activity.     

Activated mesangial cells induce glomerular endothelial cells proliferation in rat anti‐Thy‐1 nephritis through VEGFA/VEGFR2 and Angpt2/Tie2 pathway

ObjectivesWe aimed to investigate the underlying mechanism of endothelial cells (ECs) proliferation in anti‐Thy‐1 nephritis.Materials and methodsWe established anti‐Thy‐1 nephritis and co‐culture system to explore the underlying mechanism of ECs proliferation in vivo and in vitro. EdU assay kit was used for measuring cell proliferation. Immunohistochemical staining and immunofluorescence staining were used to detect protein expression. ELISA was used to measure the concentration of protein in serum and medium. RT‐qPCR and Western blot were used to qualify the mRNA and protein expression. siRNA was used to knock down specific protein expression.ResultsIn anti‐Thy‐1 nephritis, ECs proliferation was associated with mesangial cells (MCs)‐derived vascular endothelial growth factor A (VEGFA) and ECs‐derived angiopoietin2 (Angpt2). In vitro co‐culture system activated MCs‐expressed VEGFA to promote vascular endothelial growth factor receptor2 (VEGFR2) activation, Angpt2 expression and ECs proliferation, but inhibit TEK tyrosine kinase (Tie2) phosphorylation. MCs‐derived VEGFA stimulated Angpt2 expression in ECs, which inhibited Tie2 phosphorylation and promoted ECs proliferation. And decline of Tie2 phosphorylation induced ECs proliferation. In anti‐Thy‐1 nephritis, promoting Tie2 phosphorylation could alleviate ECs proliferation.ConclusionsOur study showed that activated MCs promoted ECs proliferation through VEGFA/VEGFR2 and Angpt2/Tie2 pathway in experimental mesangial proliferative glomerulonephritis (MPGN) and in vitro co‐culture system. And enhancing Tie2 phosphorylation could alleviate ECs proliferation, which will provide a new idea for MPGN treatment.     

Potential use of isolated glomeruli and cultured mesangial cells as in vitro models to assess nephrotoxicity

The purpose of this short review is to present the potential of using isolated glomeruli and cultured mesangial cells as two differentin vitro models to assess the glomerular effect of molecules with nephrotoxic properties. The advantage of using isolated renal glomeruli is that they conserve the architecture of this anatomical region of the kidney; moreover, they are free of any vascular, nervous or humoral influences derived from other regions of the kidney. Mesangial cells are perivascular pericytes located within the central portion of the glomerular tuft between capillary loops. Mesangial cells have a variety of functions including synthesis and assembly of the mesangial matrix, endocytosis and processing of plasma macromolecules, and control of glomerular hemodynamics, mainly the ultrafiltration coefficient K _f, via mesangial cell contraction or release of vasoactive hormones. Most authors agree that mesangial cells play a major role in glomerular contraction, filtration surface area, and K _f regulation. One of the major effects of toxicants on glomerular structures is contraction. We can assess quantitatively the degree of toxicant-induced mesangial cell contraction or glomerular contraction by measuring the changes in planar cell surface area or apparent glomerular cross-sectional area after exposition to the toxicant. Thesein vitro models can also reveal glomerular effects of xenobiotics that are difficult or impossible to observe in vivo. In addition, these studies permit a fundamental examination of the mechanism of action of xenobiotics on glomerular cells, including the possibility that at least a part of their effects are mediated by local mediators released by glomerular cells. We review the effects and the mechanisms of action of several toxicants such as gentamicin, cyclosporin, cisplatin, and cadmium on isolated glomeruli or cultured mesangial cells. As suchin vitro results confirmin vivo renal hemodynamic changes caused by toxicants, we conclude that these models are fruitful tools for the study of renal toxicity. Thesein vitro systems might also serve as a predictive tool in the evaluation of drugs inducing changes in glomerular filtration rate and as a way to propose protective agents against these dramatic hemodynamic effects. This revised version was published online in July 2006 with corrections to the Cover Date.     

Isolated glomeruli and cultured mesangial cells as in vitro models to study immunosuppressive agents

Immunosuppressive agents, such as cyclosporin A (CsA), by their vasoconstrictive properties, induce in vivo in patients and rodents a dramatic fall in renal hemodynamics. The aim of this study is to review the ability of some physiological and/or pharmacological agents which are supposed to be involved in the renal physiopathology of CsA to prevent the contraction induced by CsA in two in vitro glomerular models. Isolated glomeruli are obtained by a sieving method from male Sprague-Dawley rat superficial cortex. Mesangial cells from these isolated glomeruli are cultured in RPM1 1640 medium with 20% FCS in5% CO ₂ atmosphere. The area of isolated glomeruli and cultured mesangial cells is assessed by an image analyzer with a video camera. Each glomeruli and cell is its own control and is photographed before incubation with any drug (T0) and then during incubation at 5, 10, 20, and 30 min. Incubations are performed during 30 min with 10^–6 mol/L CsA either with a 10 min pretreatment with the vasoactive agent or without pretreatment. CsA alone induces a time- and dose-dependent decrease in glomerular structure area (-4.7% at 10 min,-10.3% at 20 min, and-12.0% at 30 min for isolated glomeruli); Cremophore excipient or control solute does not induce any significant decrease in surface area. CsA with 10^–6 mol/L verapamil pretreatment induces only a slight decrease:-1.5% at 10 min,-3.0% at 20 min, and-4.8% at 30 min. Calcium blockers nifedipine and felodipine produce similar results. Likewise with 10^–8 mol/L prostacyllin analog (iloprost), only a slight area decrease in mesangial cells is noted:-1.3% at 5 min,-1.8% at 10 min, and-3.3% at 20 min; with 10^–6 mol/LTXA₂ synthesis imhibitor (CGS 12970) the results are-2.0% at 10 min,-3.6% at 20 min, and-4.3% at 30 min. Finally, a similar protective effect can be noted with 10^–5 mol/L theophylline:-0.4;-1.5 and-1.9% at 10, 20, and 30 min.In conclusion, CsA-induced contraction in two in vitro glomerular models can be partially or even totally prevented by pretreatment with various pharmacological agents.Abbreviations CsA cyclosporin A - TX thromboxane - PSA planar surface area     

High-Level Expression of Recombinant Active Human Renin in Sf-9 Cells: Rapid Purification and Characterization

Recombinant human (rh) renin was expressed in Sf-9 insect cells. Baculovirus-infected Sf-9 cells produced active rh-renin in the late stage of cultivation. The rh-renin was purified after 5 d of culture by two steps of column chromatography. Approximately 0.61 mg of pure rh-renin was obtained from 200 ml of culture medium with a yield of 35.3%.     

Uptake and metabolism of lipoprotein-X in mesangial cells

Progressive glomerulosclerosis is a major complication in patients with familial lecithin:cholesterol acyltransferase (LCAT) deficiency. The lack of LCAT activity results in the accumulation of an abnormal lipoprotein, lipoprotein-X (Lp-X), in the plasma of these patients. Lipoprotein-X contains high levels of unesterified cholesterol and phosphatidylcholine. Lp-X may play a role in the accumulation of lipids in the kidney, which in turn may lead to glomerulosclerosis. The objective of this study is to examine the uptake and metabolism of Lp-X by rat mesangial cells. Our results suggest that Lp-X is taken up by mesangial cells and that the lipids in Lp-X are metabolized. Lysosomes containing unesterified cholesterol and phosphatidylcholine, in a molar ratio similar to Lp-X, were synthesized to investigate the roles individual apolipoproteins (apo CI, II, III and E) play in the uptake of Lp-X. Both apo CI and CIII inhibited its uptake while apo CII (1.5 fold) and E (4 fold) stimulated t he uptake of Lp-X. Very low density lipoprotein (VLDL) and low density lipoprotein (LDL) inhibited Lp-X uptake by mesangial cells. However, at higher concentrations of high density lipoprotein (HDL), the uptake of Lp-X was stimulated. Proteoglycans have an important role in regulating the uptake of Lp-X, while cytoskeleton-dependent phagocytosis and the scavenger receptor do not appear to be involved. (Mol Cell Biochem 175: 187–194, 1997)     

Synergistic induction of osteopontin by aldosterone and inflammatory cytokines in mesangial cells

Hypertensive nephrosclerosis is characterized by activation of the renin-angiotensin-aldosterone system in combination with an inflammatory response characterized by an infiltration of T-cells and mononuclear cells, which release proinflammatory cytokines like IL-1beta/TNFalpha. In various models of experimental hypertensive disease the chemokine osteopontin (OPN) enhances further leukocyte infiltration. Therefore, we investigated the induction of OPN expression in renal mesangial cells (MCs) by aldosterone and the inflammatory cytokines IL-1beta/TNFalpha. Incubation with aldosterone resulted in a time- and concentration-dependent increase in OPN mRNA and protein. OPN mRNA expression followed a biphasic time course with an early increase between 4 and 8 h and the second phase starting at 14 h. The early phase was independent of protein synthesis, indicating a direct effect of aldosterone. Aldosterone-mediated induction of OPN was prevented by spironolactone, indicative of a receptor-mediated aldosterone effect. The mineralocorticoid receptor (MR) was identified in MCs by RT-PCR and immunoprecipitation, and shown to interact with a putative aldosterone-response element of the OPN promoter. The proinflammatory cytokines IL-1beta and TNFalpha only marginally affected OPN expression in MCs. However, coincubation of aldosterone and the cytokines synergistically increased OPN mRNA and protein levels. Since the synergistic effect on OPN mRNA was inhibited by diphenyleneiodonium, we assume an involvement of reactive oxygen species (ROS). We conclude that the chemokine OPN is a target gene of aldosterone in renal MCs, which is activated via the MR, and that proinflammatory cytokines enhance aldosterone-dependent OPN expression. In vivo, this may result in further leukocyte infiltration aggravating hypertensive nephrosclerosis.     

高糖对原代培养人肾小球系膜细胞表达MMP-9、TIMP-1的影响

目的了解高糖对原代培养的人肾小球系膜细胞表达MMP-9、TIMP-1和MMP-9/TIMP-1的影响,进一步探讨糖尿病肾病的发病机制。方法取自愿水囊引产的胎儿肾,解剖取肾皮质剪碎,应用肾皮质组织块法合优生选择法对人肾小球系膜细胞进行原代培养。ELISA方法检测MMP-9、TIMP-1的表达变化。结果与正常组相比较,高糖组MMP-9在24h、48h、72h均显著降低（P〈0.01）,TIMP-1在24h、72h可显著升高（P〈0.05）,48h表达降低;MMP-9/TIMP-1的比值在24h、48h、72h均显著降低（P〈0.01）。结论高糖能够降低MMP-9/TIMP-1,与肾小球系膜细胞细胞外基质降解能力降低密切相关。