Pericyte adhesion is impaired on extracellular matrix produced by endothelial cells in high hexose concentrations

Aims/hypothesis: Thickening of the basement membrane and selective loss of pericytes are early events in diabetic retinopathy. We aimed at checking whether pericyte interaction with extracellular matrix produced by endothelial cells is influenced by the hexose concentrations in which endothelial cells are cultured. Methods: Conditioned extracellular matrixes were obtained by growing human umbilical vein endothelial cells in media containing 28 mmol/l hexoses (d-glucose, d-galactose, l-glucose), which undergo different intracellular processing, before and after adding the inhibitors of protein glycation thiamine or aminoguanidine. Having removed the endothelium, bovine retinal pericytes were grown on such matrixes and, in separate experiments, on laminin, fibronectin or type IV collagen. Pericyte adhesion was determined by cell counts 18 h after seeding. Results: Reduced adhesion was observed on matrixes produced in high d-glucose, high d-galactose and high l-glucose. Both thiamine and aminoguanidine restored impaired pericyte adhesion when added to high d-glucose and high d-galactose, but not l-glucose. Laminin, fibronectin and type IV collagen did not consistently modify pericyte adhesion. Conclusions/interpretations: Pericyte adhesion is impaired on extracellular matrix produced by endothelium in high hexose concentrations. This could result from excess protein glycation, corrected by aminoguanidine and thiamine, rather than altered glycoprotein composition. [Diabetologia (2002) 45: 416–419] Received: 28 June 2001 and in revised form: 16 November 2001     

Regulation of rat granulosa cell differentiation by extracellular matrix produced by bovine corneal endothelial cells

The effect of bovine corneal extracellular matrix (ECM) on gonadotropin-primed rat granulosa cells in vitro was studied by examining the following parameters: 1) rate of cell attachment to culture dishes; 2) modulation of cell morphology; 3) specific binding of [125I]human(h)CG to LH/hCG receptors; 4) cAMP response to hCG stimulation; and 5) basal and hCG stimulated progesterone production. Attachment of cells to culture dishes occurred significantly earlier on ECM, as compared with uncoated dishes (6 h vs. 24 h). Cells grown on ECM were epitheloid and organized in multilayer aggregates, closely resembling their organization in the intact wall of the ovarian follicle. In contrast, cultures on uncoated dishes grew as a monolayer of markedly flattened cells. A 2-fold increase in number of LH/hCG receptors occurred on ECM within 48 h, probably due to de novo synthesis. Scatchard analysis revealed no change in hormone affinity to the receptor during the culture period [association constant (Ka) = 2.5 X 10(10)M-1 for hCG]. Cells grown on ECM had a parallel increase in cAMP responsiveness to hCG stimulation. Cells grown in serum-free medium on ECM-coated dishes preserved only 50% of LH/hCG receptors and cAMP responsiveness after 48 h. Cells cultured on ECM showed a marked elevation in progesterone production even in the absence of gonadotropin stimulation, whereas cells grown on uncoated dishes almost completely lost their ability to produce progesterone both in the presence and absence of hCG. These results indicate that ECM plays a substantial role in the maintenance and further propagation of granulosa cell differentiation in vitro.     

高糖对人肾小球系膜细胞增殖及细胞外基质的影响

目的 观察不同浓度的葡萄糖对人肾小球系膜细胞增殖的影响及对细胞外基质纤维连接蛋白(Fn),Ⅳ型胶原(ColⅣ)的影响.方法 体外培养人肾小球系膜细胞株,分别加入葡萄糖终浓度为5.5、10、20、30、40 mmol/L进行处理,于不同时间段(12、24、48、72 h)用MTT法检测肾小球系膜细胞的增殖情况,ELISA法检测培养48 h后条件培养基中Fn及ColⅣ的含量.结果 高糖作用12、24、48、72 h均能促进细胞的增殖,且随着葡萄糖浓度升高作用时间的延长促进作用增强.检测细胞上清液的Fn和ColⅣ.与对照组相比,30 mmol/L D-葡萄糖作用48 h后,Fn和ColⅣ表达增高.结论 高浓度葡萄糖对系膜细胞增殖作用具有量效及时效关系,我们选择30 mmol/L浓度的葡萄糖作用48 h为最合适的细胞刺激条件.高浓度葡萄糖可促进系膜细胞细胞外基质的产生,而系膜细胞细胞外基质过度表达,可以直接导致细胞外基质的积聚,从而导致肾小球硬化的发生.     

高糖对大鼠胰星状细胞增殖和细胞外基质合成的影响

目的探讨高糖刺激对大鼠胰星状细胞(pancreatic stellate cell, PSC)增殖和细胞外基质(extracellular matrix, ECM)合成的影响.方法分离培养大鼠PSC,取传第3～5代细胞,分别用正常葡萄糖(5.6 mmol/L葡萄糖)(正常对照)、高葡萄糖(25 mmol/L葡萄糖)(高糖组)和甘露醇(5.6 mmol/L葡萄糖+19.4 mmol/L甘露醇)(等渗对照组)处理5天后,用MTT法、3H-Thymidine掺入和3H-Proline掺入法分别检测细胞增殖、DNA合成和总胶原合成,同时用放免法检测细胞培养上清中Ⅲ型前胶原氨基末端多肽(amino-terminal propeptide of type Ⅲ procollagen, PⅢNP)和透明质酸(hyaluronic acid, HA)含量.结果与等渗对照组比较,高糖组PSC增殖、DNA合成、总胶原合成和细胞上清HA含量均显著增加(P<0.05),但细胞上清PⅢNP含量无显著性差异(P>0.05).结论高糖可刺激PSC增殖与胶原合成,参与PSC活化.体内高糖血症可能是PSC活化的机制之一.     

高糖对大鼠胰星状细胞增殖和细胞外基质合成的影响

目的 探讨高糖刺激对大鼠胰星状细胞(pancreatic stellate cell,PSC)增殖和细胞外基质(extracellular matrix,ECM)合成的影响。方法 分离培养大鼠PSC,取传第3～5代细胞,分别用正常葡萄糖(5.6mmol/L葡萄糖)(正常对照)、高葡萄糖(25mmol/L葡萄糖)(高糖组)和甘露醇(5.6mmol/L葡萄糖+19.4mmol/L甘露醇)(等渗对照组)处理5天后,用MTT法、~3H-Thymidine掺入和~3H-Proline掺入法分别检测细胞增殖、DNA合成和总胶原合成,同时用放免法检测细胞培养上清中Ⅲ型前胶原氨基末端多肽(amino-terminal propeptide of type Ⅲ procollagen,P Ⅲ NP)和透明质酸(hyaluronic acid,HA)含量。结果 与等渗对照组比较,高糖组PSC增殖、DNA合成、总胶原合成和细胞上清HA含量均显著增加(P<0.05),但细胞上清P Ⅲ NP含量无显著性差异(P>0.05)。结论 高糖可刺激PSC增殖与胶原合成,参与PSC活化。体内高糖血症可能是PSC活化的机制之一。     

Cultured retinal capillary pericytes die by apoptosis after an abrupt fluctuation from high to low glucose levels: a comparative study with retinal capillary endothelial cells

Summary A number of clinical observations concerning cases of glycemic fluctuation have prompted us to study whether or not a rapid change in blood glucose concentration can aggravate retinal microvascular pathology during the early stage of diabetic retinopathy. We conducted a comparative study of retinal capillary pericytes and endothelial cells in vitro. Both types of cells, either in single culture or in co-culture, were initially incubated in medium with high glucose (20–40 mmol/l), followed by a rapid reduction of glucose to 3.5, 1, or 0.5 mmol/l. This type of reduction of extracellular glucose resulted in depletion of intracellular glucose, occurring much faster in pericytes than in endothelial cells. The abrupt reduction in glucose caused pericyte cell shrinkage and nuclear condensation associated with DNA fragmentation, followed by loss of cell viability. All of these pericyte changes are apoptosis-like characteristics. This apoptotic process was prevented by the addition of cycloheximide, a protein synthesis inhibitor, or by platelet-derived growth factor BB, which is a known competent factor for pericyte growth. In analysis of signalling pathways during the abrupt fluctuation of glucose, the occurrence of pericyte apoptosis was an intracellular calcium-dependent, protein kinase C and protein kinase A mediated, and poly (ADP-ribose) synthetase-dependent process. Interestingly, a larger degree of DNA fragmentation was observed with a higher magnitude and a longer duration of pre-existing hyperglycaemia. These results suggest that the magnitude and duration of pre-existing hyperglycaemia prime the apoptotic responsiveness of pericytes. Retinal capillary endothelial cells, after an identical glucose fluctuation treatment did not undergo an apoptotic process.Abbreviations RCEC Retinal capillary endothelial cells - IDDM insulin-dependent diabetes mellitus - FCS fetal calf serum - DMEM Dulbecco's modified Eagle's medium - PDGF platelet-derived growth factor - PKC protein kinase C - PKA protein kinase A - PMA phorbol 12-myristate 13-acetate     

Regulatory role of eicosanoids in extracellular matrix overproduction induced by long-term exposure to high glucose in cultured rat mesangial cells

Summary Accumulation of extracellular matrix in the mesangium and altered renal eicosanoid synthesis are two prominent features of diabetic glomerular disease. We investigated the relationship between eicosanoid and extracellular matrix production in rat mesangial cells cultured under high glucose vs normal glucose conditions. Long-term exposure of rat mesangial cells to high glucose, but not to iso-osmolar mannitol, significantly increased extracellular matrix accumulation and gene expression and transforming growth factor- (TGF-) mRNA levels, and decreased prostaglandin (PG) E₂ synthesis without affecting production of either thromboxane (TX) B₂ or PGF₂, with respect to cells incubated in normal glucose. Addition of exogenous PGE₂ resulted in a dose-dependent reduction of matrix protein and mRNA levels and TGF- gene expression in cells cultured in either normal or high glucose conditions, whereas exposure to exogenous PGF₂ produced a significant increment in matrix production and matrix and TGF- gene expression in cells grown in normal glucose, but only a slight increase in those cultured in high glucose. Stimulation of endogenous endoperoxide metabolism towards PGE₂ and PGF₂ synthesis with FCE-22,178, a drug originally developed as TXA₂ synthase inhibitor, resulted in a dose-dependent decrease in matrix accumulation and matrix and TGF- gene expression which was suppressed by co-incubation with the cyclo-oxygenase inhibitor feno-profen blocking the FCE-22,178-enhanced PG production. In both cell lines, the rate of synthesis of TXA₂ was very low and the selective blockade of its synthesis (by two other TXA₂ synthase inhibitors, OKY-046 and Ridogrel) or action (by the TXA₂ receptor antagonist BM-13,177) did not alter matrix production or TGF- mRNA levels. These results suggest that the cyclo-oxygenase pathway is involved in the regulation of matrix changes induced by high glucose in rat mesangial cells; the reduced production of PGE₂ may enhance the synthesis or potentiate the effect of stimulators of ECM formation such as TGF-, whereas TXA₂ does not appear to be involved. These data also indicate that glucose-enhanced mesangial matrix accumulation may be prevented by exogenous PGE₂ or by drugs capable of increasing endogenous PGE₂ synthesis.Abbreviations AGE Advanced glycosylation end-products - ECM extracellular matrix - PG prostaglandin - RMC rat mesangial cells - TGF- transforming growth factor- - TX thromboxane - Cox cyclo-oxygenase     

Modulation by high glucose of adhesion molecule expression in cultured endothelial cells

Summary We evaluated the influence of high ambient glucose on cellular expression of adhesion molecules, known to mediate endothelial interaction of leucocytes and monocytes. Paired cultures of individual isolates of human umbilical vein endothelial cells (HUVECs) were studied by fluorescence activated cell sorter analysis after exposure to 30 vs 5 mmol/l glucose. Incubation of HUVECs for 24 h in 30 mmol/l glucose increased ICAM-1 (intercellular adhesion molecule-1; 116.4±16.9% of control, p 0.05), but not PECAM (platelet endothelial cell adhesion molecule) expression, compared to cultures kept in 5 mmol/l glucose. Long-term exposure (13±1 days) of HUVECs to 30 mmol/l glucose increased expression of ICAM-1 to 122.5±32.2% (p<0.002) and reduced that of PECAM to 86.9±21.3% vs the respective control culture in 5 mmol/l glucose (p<0.02). Stimulation of confluent HUVECs, kept in 30 vs 5 mmol/l glucose for 13±1 days, with 20 U/ ml interleukin-1 for 24 h (ICAM-1) and 4 h (endothelial leukocyte adhesion molecule 1) resulted in reduced ICAM-1 (84.8±27.0%, p<0.05) and endothelial leukocyte adhesion molecule-1 (87.6±22.4%, p<0.05) expression vs control cells, while that of PECAM (t: 24 h) and vascular cell adhesion molecule-1 (t: 16 h) remained unchanged. In conclusion, it appears that differences in expression of adhesion molecules on HUVECs in response to high glucose reflects endothelial glucose toxicity, which may also induce endothelial dysfunction in diabetes.Abbreviations HUVECs Human umbilical vein endothelial cells - ICAM-1 intercellular adhesion molecule-1 - PECAM platelet endothelial cell adhesion molecule - ELAM-1 endothelial leukocyte adhesion molecule-1 - VCAM-1 vascular cell adhesion molecule-1 - IL-1 interleukin-1 - FACS fluorescence activated cell sorter - FCS fetal calf serum - PBS phosphate buffered saline     

高糖及糖尿病患者白细胞对内皮细胞明胶酶的影响

目的观察高糖环境及糖尿病患者白细胞与内皮细胞共同孵育后白细胞与内皮细胞的黏附率及92000明胶酶（MMP-9）的变化规律。方法培养人脐静脉内皮细胞，用不同浓度的葡萄糖培养液共同孵育，计算细胞黏附率和应用ELISA方法测定MMP-9水平。结果高糖环境可使白细胞与内皮细胞黏附率增加，随共育时间的延长此作用加强。在高糖环境中培养的内皮细胞MMP-9水平显著升高，加入糖尿病患者白细胞后此种趋势更加明显。结论高糖环境促使内皮细胞分泌MMP-9增加，糖尿病患者白细胞对内皮细胞具有细胞毒作用。     

β-连环蛋白在高糖诱导的内皮细胞损伤中的作用

内皮细胞功能紊乱被认为是高糖诱导血管并发症的始动因素和加重的基础。Wnt／β-连环蛋白信号途径在内皮细胞增生和凋亡的调控上起着重要作用,这条信号通路关键调节靶点是胞浆中β-连环蛋白的水平,它决定了Wnt靶基因的活化水平。当内皮细胞处于高糖环境中,β-连环蛋白减少,Wnt信号减弱,内皮细胞抗凋亡能力下降,增殖受到抑制,从而导致血管并发症。除此以外,在高糖作用下,β-连环蛋白介导的内皮细胞间黏附连接的破坏将导致内皮通透性增高,使蛋白质等大分子物质漏出血管外,同样造成血管功能紊乱。     

The effects of high glucose and atorvastatin on endothelial cell matrix production.

BACKGROUND: Statins are known to enhance atherosclerotic plaque stability through influences on extracellular matrix homeostasis. Net matrix production reflects the relative balance of matrix production and degradation through enzymes such as matrix metalloproteinases (MMPs) and their inhibitors, tissue inhibitor of MMP (TIMPs). The effects of statins on endothelial cell production of these parameters following co-exposure with a proatherogenic stimulus such as high glucose are not known. METHODS: Human endothelial cells were exposed for 72 h to 5 mm (control) or 25 mm (high) glucose +/- atorvastatin (1 micromol/l). Extracellular matrix homeostasis was assessed by measuring matrix metalloproteinase (MMP)-2 secretion, tissue inhibitor of MMP (TIMP)-1 and -2 secretion and net collagen IV production. Results were expressed as percentage +/- SEM of control values. RESULTS: Exposure to high glucose increased cellular collagen IV expression to 190.1 +/- 11.7% (P < 0.0001) of control levels. No change in MMP-2 secretion (111.6 +/- 5.2%; P > 0.05) was observed but both TIMP-1 and TIMP-2 expression were increased to 136.3 +/- 6.4% and 144.0 +/- 27.5%, respectively (both P < 0.05). The presence of atorvastatin in high glucose conditions reduced collagen IV expression to 136.1 +/- 20.6%. This was paralleled by increased secretion of MMP-2 to 145.8 +/- 7.8% (P < 0.01), increased TIMP-2 expression to 208.0 +/- 21.3% (P < 0.005 compared with high glucose) but no change in TIMP-1 expression (155.1 +/- 14.6%) compared with high glucose alone. The presence of atorvastatin in control conditions did not affect levels of collagen IV expression (114.5 +/- 13.2%). CONCLUSIONS: Endothelial cell exposure to high glucose was associated with a MMP/TIMP profile that increased extracellular matrix production which was attenuated by concurrent exposure to atorvastatin. Consequently, a mechanism by which the atherosclerotic plaque regression that is observed in patients taking these drugs has been demonstrated.     

艾塞那肽抑制高糖诱导内皮细胞凋亡的作用机制

在正常糖浓度(5.5 mmol/L)和高糖(33 mmol/L)培养的人脐静脉内皮细胞(HUVECs)分别加入不同浓度的艾塞那肽并干预不同时间后,噻唑蓝(MTF)法检测细胞活力,应用流式细胞仪检测细胞早期凋亡率,Western印迹法检测蛋白激酶B(Akt)磷酸化、Bcl-2和Bax蛋白表达水平.结果显示,HUVECs经高糖培养48和72 h后,细胞活力明显下降(P＜0.01).经1、10和100 nmol/L艾塞那肽干预48 h后,细胞活力明显增加,并呈浓度依赖性(P＜0.01).与正常糖浓度组比较,高糖组细胞凋亡率升高,Akt磷酸化和Bcl-2蛋白表达水平下降,Bax蛋白表达增加,Bcl-2/Bax比值降低(P＜0.01).艾塞那肽干预后,细胞凋亡率下降,Akt磷酸化和Bcl-2蛋白表达增加,Bax蛋白表达下降,Bcl-2/Bax比值升高(P＜0.01),而艾塞那肽的作用可被磷酸肌醇3激酶(PI3K)抑制剂LY294002所对抗(P＜0.01).提示艾塞那肽可通过PI3 k/Akt信号通路调节Bcl-2/Bax蛋白表达来抑制高糖诱导的内皮细胞凋亡,起到保护内皮细胞的作用.     

表没食子儿茶素没食子酸酯对高糖环境下内皮细胞氧化应激的影响

目的研究不同剂型表没食子儿茶素没食子酸酯（EGCG）对高糖诱导人脐静脉内皮细胞（HUVEC）氧化应激损伤所引起凋亡的抑制作用及人核因子-κB P65（NF-κB P65）表达的影响。方法从新鲜脐带中分离培养HUVEC。用高糖诱导HUVEC表达NF-κB P65,实验组加入不同浓度的EGCG（12．5、25、50、100、200μmol／L）进行干预,PCR检测NF-κB P65mRNA的表达,AV-PI法检测凋亡细胞。结果高糖可诱导HUVEC凋亡,NF-κB P65表达增高;EGCG可抑制NF-κB P65的表达,降低凋亡指数,具有一定的时效关系、剂量关系。结论EGCG可在一定程度上抑制高糖诱导的氧化应激损伤所致的细胞凋亡。EGCG可能是通过抑制高糖所致的NF-κB增高,从而调控HUVEC细胞凋亡过程,发挥对HUVEC的保护作用。     

高糖诱导人脐静脉内皮细胞凋亡的机制

目的 探讨高糖诱导人脐静脉内皮细胞凋亡的机制.方法 (1)将人脐静脉内皮细胞分为3组:正常对照组(5.5 mmol/L葡萄糖)、高渗对照组(5.5 mmol/L葡萄糖+27.5 mmol/L甘露醇)、高糖组(11 mmol/L、22 mmol/L、33 mmol/L、44 mmol/L葡萄糖),以上各组细胞培养48小时,采用流式细胞术及Hoechst 33258核染色观察各组细胞凋亡情况.(2)人脐静脉内皮细胞分为3组:正常对照组(5.5 mmol/L葡萄糖)、高糖组(33 mmol/L葡萄糖)、高糖+雷帕霉素组(雷帕霉素预处理24小时后加入33 mmol/L葡萄糖),以上分组细胞均培养48小时,Western blot分析各组马铃薯球蛋白(Tuberin)、P-Tuberin、核糖体蛋白S6激酶(P70S6K)、P-P70S6K、bcl-2、Bax蛋白表达水平.结果 (1)与正常对照组早期凋亡率(2.9200 +0.0159)％相比,高糖组明显增加,且呈剂量依赖性[(4.8400 ±0.0092)％、(6.7200±0.0041)％、(8.4900 ±0.0047)％、(9.9500±0.0124)％,P均＜0.05)];高渗对照组早期凋亡率(2.9200±0.0023)％与正常对照组比较差异无统计学意义(P＞0.05);与正常对照组晚期凋亡率(2.3700±0.0059)％比较,高糖组晚期凋亡率显著增加,且呈剂量依赖性[(3.2500±0.0280)％、(4.3600±0.0191)％、(5.9800±0.0083)％、(7.0100±0.0099)％,P均＜0.05];高渗对照组细胞凋亡率为(2.3600±0.0205)％,与正糖对照组比较差异无统计学意义(P＞0.05).(2)与正常对照组比较,高糖组P-Tuberin/Tuberin(1.2774±0.0026比1.0052±0.0012)、P-P70S6K/P70S6K(1.2129 ±0.0065比0.8157 ±0.0030)、Bax/β-actin (0.7484±0.0004比0.3966 ±0.0029)表达水平均显著升高,差异有统计学意义(P均＜0.05),bcl-2/β-actin表达明显降低(0.2949±0.0010比0.6398±0.0011,P＜0.05);高糖+雷帕霉素组P-P70S6K/P70S6K(0.9287±0.0019)、Bax/β-actin(0.5558±0.0052)表达水平低于高糖组(P＜0.05),bcl-2/β-actin (0.4546±0.0023)表达高于高糖组(P＜0.05).结论 高糖可能通过激活Tuberin/mTOR活性,从而降低bcl-2、增加Bax表达而导致血管内皮细胞凋亡.     

大鼠肺细胞外基质老化的实验研究

目的观察细胞外基质（ＥＣＭ）在肺老化中的作用。方法利用免疫组化技术和生化测定方法，观察肺老化时ＥＣＭ成分相对含量，在不同年龄组间进行对比分析。结果纤维粘连蛋白（Ｆｎ），老年大鼠（０．１４±０．０４）较中年大鼠（０．０８±０．０２）、幼年大鼠（０．０８±０．０１）增多；层粘连蛋白（Ｌｎ），老年大鼠（０．０５±０．０１）较中年大鼠（０．１０±０．０２）、幼年大鼠（０．１６±０．０３）减少；Ⅳ型胶原，老年大鼠（０．０８±０．０２）较中年大鼠（０．１１±０．０２）、幼年大鼠（０．１８±０．０５）减少。各年龄组间氨基多糖（ＧＡＧ）总量未见明显改变，但其成分构成比发生了一些改变，和中、幼年鼠相比，老年鼠肺透明质酸减少，硫酸肝素相应增高。结论推测这些变化与肺老化存在着一定的联系     

游离脂肪酸及高糖对内皮细胞功能的影响研究

目的 探讨游离脂肪酸及高糖对人脐静脉内皮细胞(HUVECs)的功能的影响及可能机制.方法 研究游离脂肪酸及高糖对血管内皮细胞功能指标一氧化氮(NO)和可溶性细胞间黏附分子-1(sICAM-1)的影响;用激光共聚焦显微镜观察游离脂肪酸及高糖对PKCα、PKCδ的影响.结果 不同浓度游离脂肪酸及高糖均可诱导内皮细胞功能紊乱及PKCα及PKCδ表达位置转移及表达增强,高糖中加入游离脂肪酸可使变化更显著.结论 游离脂肪酸及高糖均可导致内皮细胞功能紊乱,可能部分是通过PKCα及PKCδ途径来实现的.     

A pathway of coagulation on bovine capillary endothelial cells

In this report cultured bovine capillary endothelial cells are demonstrated to specifically bind factors IX and X and also their activated forms. Bound factor IXa and cell-associated factor VIII can activate factor X. The product of this reaction, factor Xa, can then interact with a factor V-like molecule expressed by capillary endothelial cells promoting thrombin formation. The thrombin formed can cleave fibrinogen leading to release of fibrinopeptide A and clot formation. Endotoxin-treatment of capillary endothelial cells leads to induction of tissue factor activity which, in the presence of factor VIIa, promotes activation of factors IX and X. The amount of factor Xa formed endotoxin-treated endothelial cells incubated with factors VIIa, IX, VIII and X, is 8 times greater than cells incubated with factors VIIa and X alone. This indicates that on the perturbed endothelial cell surface factors VIII and IX do play an important role in factor X activation by the tissue factor pathway. The perturbed capillary endothelial cell can thus provide a model of the thrombotic state promoting initiation and propagation of a procoagulant pathway leading to thrombin formation. This pathway of coagulation is endothelial cell-dependent, since it requires expression of tissue factor and factor V by capillary endothelial cells, as well as interaction of coagulation factors with the surface of capillary endothelial cells.     

去甲斑蝥素不依赖钙调蛋白磷酸酶信号通路抑制高糖刺激肾小管上皮细胞细胞外基质的表达

目的:在证实去甲斑蝥素(norcantharidin,NCTD)能减轻糖尿病肾病(DN)大鼠肾间质纤维化和抑制高糖刺激的肾小管上皮细胞细胞外基质表达的基础上,观察NCTD对高糖刺激的肾小管上皮细胞钙调蛋白磷酸酶(calcineurin,CaN)通路的影响,探讨NCTD抗DN肾小管间质纤维化与其抑制CaN的关系。方法:常规培养人肾小管上皮细胞(HK-2),转染CaN siRNA,细胞分五组:(1)正常糖组(D-glucose5.5mmol/L);(2)高糖组(HG,D-glucose30mmol/L);(3)高糖+CaN siRNA组;(4)高糖+CaN siRNA+NCTD(5mg/L)组;(5)高糖+NCTD(5mg/L)组。采用Western-blot、免疫荧光和实时定量PCR,观察NCDT对HK-2细胞CaN/NFAT通路的影响,明确CaN siRNA的干扰效果。采用Western blot,检测NCTD对转染CaN siRNA后的HK-2细胞纤维连接蛋白(FN),胶原蛋白IV(Collagen IV,Col IV)及转化生长因子β1(TGF-β1)蛋白表达的影响。结果:高糖可促进HK-2细胞CaNmRNA及蛋白的表达,NCTD可在基因及蛋白水平抑制CaN的表达(P0.05)。免疫荧光发现CaN下游活化T细胞核因子(NFATc)在正常对照组中存在于胞质,高糖刺激后细胞核内开始表达,高糖刺激30min后发生明显的核转位,NCTD能在一定程度上抑制核转位的发生,并能减少高糖刺激后核内NFATc蛋白的表达。转染CaN siRNA后,高糖刺激后HK-2细胞中CaN mRNA以及蛋白表达均降低,而FN,Col IV以及TGF-β1蛋白水平表达都明显增强(P0.05)。NCTD可抑制转染CaN siRNA后高糖刺激的HK-2细胞FN,Col IV和TGF-β1的表达。结论:NCTD能下调肾小管上皮细胞CaN表达,阻断CaN/NFATc信号通路;但NCTD抑制高糖刺激后肾小管上皮细胞细胞外基质的表达,与其阻断CaN/NFATc信号通路无关。     

罗格列酮对高胰岛素培养的内皮细胞一氧化氮的影响及其机制研究

目的观察罗格列酮（RGZ）对高胰岛素培养的人脐静脉内皮细胞（HUVEC）NO浓度和内皮型一氧化氮合酶（eNOS）、磷酯酰肌醇3激酶（P13K）和蛋白激酶B（PKB）表达的影响,探讨RGZ改善高胰岛素状态下内皮功能障碍的信号转导机制。方法高浓度胰岛素培养HUVEC72h,并用不同浓度的RGZ进行干预。检测NO浓度,PI3K mRNA的表达,PKB、eNOS总蛋白和PKB丝氨酸473（PKB-Ser473）、eNOS丝氨酸1177（eNOS-Ser1177）的磷酸化表达。结果高浓度胰岛素培养HUVEC能呈剂帚和时间依赖性地降低N0的浓度,抑制内皮细胞P13KmRNA表达和PKB-Ser473、eNOS-Ser1177的磷酸化。用RGZ干预能硅著升高高胰岛素培养的内皮细胞NO的浓度和PKB、eNOS的磷酸化,增强PI3KmRNA表达;eNOS和P13K阻断剂均能阻断RGZ对高胰岛素培养的内皮细胞中NO浓度的升高,PI3K阻断剂还能阻断RGZ对高胰岛素培养内皮细胞PKB、eNOS的磷酸化。结论高胰岛素能下调P13K／PKB／eNOs信号通路而抑制内皮细胞NO的产生,RGZ能通过上调PI3K／PKB通路而增强高胰岛素培养的内皮细胞eNOS的活性和NO的产生。