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Quercetin can reverse high glucose-induced inhibition of neural cell proliferation, and therefore may have a neuroprotective effect in diabetic peripheral neuropathy. It is dififcult to obtain pri-mary Schwann cells and RSC96 cells could replace primary Schwann cells in studies of the role of autophagy in the mechanism underlying diabetic peripheral neuropathy. Here, we show that under high glucose conditions, there are fewer autophagosomes in immortalized rat RSC96 cells and primary rat Schwann cells than under control conditions, the proliferative activity of both cell types is signiifcantly impaired, and the expression of Beclin-1 and LC3, the molecular mark-ers for autophagy, is signiifcantly lower. After intervention with quercetin, the autophagic and proliferative activity of both cell types is rescued. These results suggest that quercetin can allevi-ate high glucose-induced damage to Schwann cells by autophagy.
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Iron overload can lead to cytotoxicity, and it is a risk factor for diabetic peripheral neuropathy. However, the underlying mechanism remains unclear. We conjectured that iron overload-induced neurotoxicity might be associated with oxidative stress and the NF-E2-related factor 2 (Nrf2)/ARE signaling pathway. As an in vitro cellular model of diabetic peripheral neuropathy, PC12 cells ex-posed to high glucose concentration were used in this study. PC12 cells were cultured with ferric ammonium citrate at different concentrations to create iron overload. PC12 cells cultured in ferric ammonium citrate under high glucose concentration had significantly low cellviability, a high rate of apoptosis, and elevated reactive oxygen species and malondialdehyde levels. These changes were dependent on ferric ammonium citrate concentration. Nrf2 mRNA and protein expression in the fer-ric ammonium citrate groups were inhibited markedly in a dose-dependent manner. Al changes could be inhibited by addition of deferoxamine. These results indicate that iron overload aggravates oxidative stress injury in neural cells under high glucose concentration and that the Nrf2/ARE sig-naling pathway might play an important role in this process.
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氨基胍减轻高糖培养系膜细胞的肥大程度与降低周期素激酶抑制物p27有关
Wolf等发现无血清高糖培养导致系膜细胞(mesangial cell,MC)停顿于G1[1],MC肥大在糖尿病肾病(DN)肾小球系膜区扩大中起重要作用[2],氨基胍(aminoguanidine,AG)可改善DN早期的肾小球系膜区扩大[3].现已明确细胞是否肥大和周期停顿均由细胞周期调节蛋白(cell cycle regulatory protein,CCRP)控制[4].其中周期素激酶抑制物p27是一种十分重要的CCRP,在DN早期的MC肥大中起重要作用[4,5].本研究旨在观察AG对高糖培养MC肥大程度及MC中p27水平的影响,从而探讨AG的作用机制.一、材料和方法1.细胞培养:SD大鼠MC按谌贻璞等[6]方法培养和鉴定(抗desmin和抗vimetin染色阳性,抗Ⅷ因子染色阴性).MC培养于含10%小牛血清的正常糖(5.56 mmol/L)DMEM中,常规置于37℃、5%的CO2培养箱中孵育,每周传代2次.实验用MC为亚培养6~8代MC.进入实验前行无血清正常糖培养24h,然后分别无血清正常糖(G100组)、高糖(25 mmol/L)(G450组)及高糖+AG(Sigma公司,AG终浓度0.25 mmol/L,溶于无血清高糖DMEM中)(G450+AG组)培养72h;另外,对MC分别转染p27错义(missense)或反义(antisense)寡核苷酸(oligodeoxynucleotide,ODN)后无血清高糖(G450+错义ODN组及G450+反义ODN组)培养72h.
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高糖培养人肾小球系膜细胞对TGF-β1、FN、Smad7表达的影响
糖尿病肾病(Diabetic Nephropathy, DN)是糖尿病常见的微血管并发症,是导致终末期肾病和糖尿病患者死亡的主要原因[1],虽然糖尿病患者的高血糖、高血脂、高血压有很多好的治疗控制方法,但DN的发病率仍然居高不下.因此,研究DN的发生机制和治疗方案是临床亟待解决的问题.Smad蛋白是目前唯一所知的转化生长因子-β1(TGF-β1)的胞内信号转导因子[2],Smad7是TGF-β1/Smad信号转导途径的负反馈调节因子,在DN的发病过程中,Smad7的表达失衡可能是致病环节之一.本文通过体外实验,观察高糖状态下TGF-β1、纤维连接蛋白(FN)增多的同时,Smad7表达的变化,探讨Smad7在细胞外基质(Extracellular Matrix,ECM)沉积中的作用.
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AIM:To investigate the effects of human induced pluripotent stem cell-derived exosomes (hiPSC-exo) on cell viability, capillary-like structure formation , and senescence in endothelial cells exposed to high glucose .METHODS: Exosomes were isolated from the conditional medium of hiPSCs and confirmed by transmission electron microscopy , nanoparticle tracking analysis , and Western blot analysis using Alix and CD63 as markers.hiPSC-exo were labeled with PKH26 for tracking.Cultured HUVECs were treated with high glucose (33 mmol/L) with or without hiPSC-exo (20 mg/L) for 48 h, and cell viability, capillary tube formation, and senescence were assessed .RESULTS:hiPSC-exo showed a typical cup shape and could be taken up by human umbilical vascular endothelial cells (HUVECs) in a concentration-dependent manner.When exposed to high glucose, viability and tube formation in HUVECs was signifi-cantly reduced, whereas the proportion of senescent cells was higher compared to that in control HUVECs (P<0.01).Furthermore, hiPSC-exo restored cell viability and capillary-like structure formation , and reduced senescence in HUVECs exposed to high glucose (P<0.01).However, hiPSC-exo had minimal effects on normal HUVECs.Therefore, stem cell-derived exosomes can promote cell proliferation, enhance capillary-like structure formation , and reduce senescence in endothelial cells exposed to high glucose . CONCLUSION:Our study highlights the role of exosomes derived from hiPSC and may provide a new strategy for maintaining vascular health, preventing vascular aging , and avoiding pathological vascular remodeling that occurs in many diseases .
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SIRT1对高糖刺激肾小球系膜细胞叉头转录因子1和p27~(kip)表达的影响
SIRT1是酵母染色沉默信息调节因子2的哺乳动物同源体,是一种依赖烟酰胺腺嘌呤二核苷酸的组蛋白去乙酰化酶活性的多功能转录调节因子,在体内参与调控哺乳动物细胞寿命的不同信号通路及糖代谢、胰岛素分泌等多条代谢途径.
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脂联素对高糖诱导系膜细胞活性氧和内皮一氧化氮合成酶产生的影响
氧化应激在糖尿病肾病(DN)发病中起重要作用[1].脂联素是脂肪细胞分泌的一种特异性蛋白质,具有抗炎、改善胰岛素抵抗、抗动脉粥样硬化、降血糖、降血脂及抗氧化作用.研究发现脂联素与DN关系密切,其血浆浓度随.肾功能不全进展而增加,原因可能是为减轻内皮和血管损伤的正反馈调节[2,3].因此,我们推测脂联素可能通过抑制氧化应激而对DN发挥保护作用,并通过本研究进一步明确脂联素抗糖尿病微血管病变的机制.
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醛固酮对高糖状态下肾小球系膜细胞血管紧张素Ⅱ受体基因表达的影响
血管紧张素Ⅱ能通过其1型受体(AT1R)和2型受体(AT2R)途径活化NF-κB[1].诱导单核细胞趋化蛋白1(MCP-1)表达[2],导致炎性反应.而醛固酮(ALD)是否也有类似的作用,尚未阐明.由于ALD能通过作用于肾脏固有细胞参与肾脏的损伤.因此,本实验通过研究ALD对高糖状态下大鼠肾小球系膜细胞(RMC)上AT1aR和AT2R基因表达的影响,探讨ALD在糖尿病肾病(DN)中的作用机制.
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小分子干扰RNA对长期高糖培养的人肾小管上皮细胞结缔组织生长因子表达的抑制作用
大量证据表明,糖尿病肾病(DN)时肾小管间质病变的严重程度与蛋白尿排泄量和肾功能的进行性下降密切相关,提示肾小管上皮细胞(TEC)损伤在DN进程中占有重要地位.
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辛伐他汀对高糖致人腹膜间皮细胞转化生长因子β1和碱性成纤维细胞生长因子分泌与表达的影响
腹膜纤维化是腹膜透析治疗的主要并发症,终导致透析效率降低甚至超滤失败.研究表明,高糖透析液能上调腹膜间皮细胞(HPMC)转化细胞生长因子β1(TGF-β1)和碱性成纤维细胞生长因子(bFGF)的表达[1],而后两者是参与腹膜纤维化的重要细胞因子[2].本研究采用RT-PCR和ELISA的方法观察辛伐他汀对高糖刺激下HPMC TGF-β1和bFGF mRNA表达和蛋白分泌的影响,探讨辛伐他汀在腹膜纤维化防治中的作用及其机制.
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褪黑素对高糖条件下培养的大鼠系膜细胞增殖、凋亡和细胞周期的影响
糖尿病肾病(DN)晚期肾脏细胞凋亡与肾功能恶化程度成正比,抑制凋亡则可延缓肾小球硬化.褪黑素(MT)是松果体分泌的神经内分泌激素,肾脏是其靶器官之一.研究显示MT对DN肾脏有明显的保护作用[1],但MT对DN晚期肾小球系膜细胞(MC)凋亡的影响尚未检索到有关报道.本试验选用大鼠MC为研究对象,来观察MT对高糖诱导的MC凋亡的影响.
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罗格列酮对高糖环境中大鼠肾小管上皮细胞的影响
罗格列酮(RGZ)是一种噻唑烷二酮类(TZDs)胰岛素增敏剂,是核转录因子过氧化物酶体增殖物激活受体γ(PPARγ)的配体.除了具有改善机体胰岛素抵抗等代谢调节作用外,TZDs还具有抗炎、影响细胞增殖和转型、抗脏器纤维化等作用,与肾脏疾病有着密切的联系.但TZDs对肾小管细胞直接作用的报道国内外较少,我们利用体外实验观察RGZ对高糖条件下肾小管细胞的影响.
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霉酚酸酯对高糖所致大鼠肾小球系膜细胞增殖的影响
霉酚酸酯(MMF)是一种新型的免疫抑制剂.本研究旨在探讨MMF对不同浓度葡萄糖所致的系膜细胞增殖及细胞外基质增多是否有抑制作用.
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ERK1/2对高糖刺激肾小球系膜细胞葡萄糖转运蛋白1和p27Kip1表达的作用
高糖是引起糖尿病肾病(DN)时肾脏肥大的始动因素.葡萄糖通过葡萄糖转运蛋白(GLUT)进入细胞.肾小球系膜细胞(GMC)主要表达GLUT1,细胞外高糖可以刺激GMC的GLUT1表达以及对糖的摄入[1].然而,高糖诱导GMC的GLUT1表达机制不甚明确.本研究利用大鼠GMC观察细胞外调节蛋白激酶(ERK1/2)对高糖诱导的GLUT1表达及细胞周期抑制蛋白(CKI)p27Kip1的影响,旨在给DN时抑制ERK1/2的活性可以阻止GLUT1的表达增高而延缓GMC肥大的假设提供理论依据.