GTF对胰岛素抵抗型3T3-L1脂肪细胞活力和葡萄糖消耗的影响

铬对于维持机体的糖、脂和蛋白质的正常代谢起着重要作用。以高铬酵母中纯化获得的葡萄糖耐量因子(GTF)为研究对象,以3T3-L1胰岛素抵抗型脂肪细胞为模式细胞,通过MTT法分析其对细胞活性的影响。通过葡萄糖氧化酶法测定胰岛素刺激和非胰岛素刺激下GTF对模式细胞葡萄糖消耗量的影响,分析其量效和时效变化规律。比较不同来源的铬对胰岛素抵抗型3T3-L1脂肪细胞的葡萄糖代谢的影响,结果表明GTF的有效剂量在0.5~1.5μg/mL范围,当GTF超过3 g/mL时,细胞活力显著受损(P0.01)。GTF作用细胞12 h后,细胞的葡萄糖消耗量显著升高(P0.05)。胰岛素刺激下,1μg/mL的GTF作用24 h,可使细胞葡萄糖消耗量提高2.5倍。相比于同等剂量的三氯化铬、吡啶酸铬,GTF促进细胞葡萄糖消耗的作用效果最显著。     

人参皂苷F2通过PI3K/Akt途径改善3T3-L1脂肪细胞胰岛素抵抗

该研究探讨了人参皂苷F2对3T3-L1脂肪细胞胰岛素抵抗的影响及其机制。将3T3-L1前脂肪细胞诱导分化成熟后,用1 μmol/L地塞米松处理48 h,建立胰岛素抵抗模型。用10 μmol/L的罗格列酮（阳性对照）和25、50、100 μmol/L人参皂苷F2处理胰岛素抵抗细胞12 h,检测细胞对2-NBDG的摄取。实验结束后用RT-qPCR检测各组细胞中葡萄糖转运蛋白4（GLUT-4）和胰岛素底物受体1（IRS-1）mRNA相对表达量,并利用Western blot检测PI3K/Akt信号通路中蛋白表达及其磷酸化水平。结果表明：与模型组相比,25、50、100 μmol/L人参皂苷F2均能促进胰岛素抵抗3T3-L1脂肪细胞对2-NBDG的摄取,分别增加了12.58%、29.07%和34.62%（p<0.05）;人参皂苷F2作用12 h后,GLUT-4和IRS-1 mRNA相对表达量以及PI3K、Akt的磷酸化水平显著提高（p<0.01）。该研究表明人参皂苷F2可通过促进胰岛素抵抗3T3-L1脂肪细胞中GLUT-4和IRS-1mRNA相对表达,增加PI3K和Akt蛋白磷酸化,从而激活PI3K/Akt信号通路,改善其糖代谢和胰岛素抵抗。     

灵芝醇提物对改善3T3-L1脂肪细胞胰岛素抵抗的作用

研究讨论灵芝醇提物对地塞米松诱导的3T3-L1脂肪细胞胰岛素抵抗的影响。采用地塞米松诱导脂肪细胞胰岛素抵抗模型,将细胞分成正常组、模型组、灵芝醇提物组、二甲双胍（阳性对照）组,检测各组的葡萄糖消耗量和甘油三酯含量,分析灵芝醇提物对胰岛素抵抗的影响。建立模型的地塞米松处理组与正常组相比,1 μmoL/L地塞米松处理72 h显著降低了3T3-L1脂肪细胞的葡萄糖消耗量（P＜0.05）,且胰岛素抵抗状态在24 h内维持稳定,脂肪细胞胰岛素抵抗模型构建成功。10、50、100 mg/L灵芝醇提物对细胞活力均无显著影响,灵芝醇提物处理细胞24 h能显著提高脂肪细胞的葡萄糖消耗量和细胞内甘油三酯的含量且呈剂量依赖性。同时灵芝醇提物处理后显著增加了胰岛素受体底物1、葡萄糖转运体-4、磷脂酰肌醇-3-激酶p110亚基、磷脂酰肌醇-3-激酶p85亚基、磷酸化蛋白激酶、磷酸化糖原合酶激酶3β蛋白的表达。结果表明灵芝醇提物通过IRS1/PI3K/AKT信号途径改善地塞米松诱导的脂肪细胞胰岛素抵抗。     

猫豆乙醇提取物对3T3-L1脂肪细胞糖脂代谢的影响

探讨猫豆乙醇提取物(MPEE)对胰岛素抵抗3T3-L1脂肪细胞糖脂代谢的影响。用含高浓度葡萄糖和高浓度胰岛素的DMEM培养基制备胰岛素抵抗3T3-L1脂肪细胞模型。模型细胞经不同浓度MPEE处理24 h后检测培养液中的葡萄糖消耗量、游离脂肪酸(FFA)、甘油、三酯甘油(TG)及肿瘤坏死因子(TNF-α)和白介素6(IL-6)水平。实时定量PCR(q RT-PCR)检测细胞中葡萄糖转运蛋白(GLUT-4)、激素敏感脂肪酶(HSL)和炎性介质[TNF-α、IL-6、单核细胞趋化蛋白-1(MCP-1)、C反应蛋白(CRP)]的m RNA表达。MPEE可促胰岛素抵抗模型细胞对葡萄糖的消耗,降低细胞中TG含量,减少FFA和甘油溢出。同时,MPEE还能抑制模型细胞TNF-α和IL-6分泌,及炎性介质(TNF-α、IL-6、MCP-1、CRP)的m RNA表达。此外,MPEE能上调细胞中GLUT-4的表达,并降低HSL的m RNA表达。结果显示,MPEE可有效刺激3T3-L1脂肪细胞消耗葡萄糖,促TG分解,减少FFA和甘油的溢出。调控细胞糖、脂代谢来改善胰岛素抵抗,并降低胰岛素抵抗发生时的炎症水平。     

白藜芦醇对大鼠脂肪细胞抗氧化及胰岛素敏感性的影响

观察白藜芦醇(resveratrol,Res)对胰岛素抵抗大鼠原代脂肪细胞的抗氧化及胰岛素敏感性的影响。培养大鼠原代脂肪细胞,用地塞米松建立胰岛素抵抗模型;添加不同剂量的白藜芦醇,检测葡萄糖的消耗量及培养基和细胞内的超氧化物歧化酶(superoxide dismutase,SOD)、丙二醛(malondialdehyde,MDA)的浓度,Western blot检测沉默信息调节因子1(silent information regulator 1,Sirt1)及胰岛素信号通路相关位点的蛋白表达及相关磷酸化水平。结果显示：Res 能增加胰岛素抵抗状态下的脂肪细胞的葡萄糖摄入量,增加SOD,降低脂质过氧化产物MDA;Res 增加Sirt1 的蛋白表达,经由胰岛素信号转导通路增加葡萄糖转运子4(glucose transporter 4,GLUT4)蛋白的转位。结果说明Res 能增加大鼠原代脂肪细胞的抗氧化能力,改善胰岛素抵抗,这可能是通过增加Sirt1 表达而实现的。     

发酵糙米乙醇提取物改善3T3-L1脂肪细胞糖脂代谢

探讨发酵糙米乙醇提取物(FBREE)对胰岛素抵抗3T3-L1脂肪细胞糖脂代谢的影响。高浓度葡萄糖加胰岛素刺激诱导3T3-L1脂肪细胞胰岛素抵抗模型。不同浓度FBREE处理细胞24 h后检测培养液中葡萄糖,游离脂肪酸(FFA),甘油,甘油三酯(TG),肿瘤坏死因子(TNF-α)和白介素6(IL-6)水平。实时定量PCR检测细胞氧化物酶体增殖激活受体γ(PPARγ),CAATT增强子结合蛋白(C/EBPα),固醇调节元件结合蛋白(SREBP1c),葡萄糖转运蛋白4(GLUT4),脂肪酸结合蛋白(a P2),蛋白酪氨酸磷酸酶1B(PTP1B),葡萄糖转运蛋白(GLUT-4),激素敏感脂肪酶(HSL)和TNF-α,IL-6,单核细胞趋化蛋白-1(MCP-1)和C反应蛋白(CRP)的m RNA表达。FBREE具有促进细胞葡萄糖利用,降低细胞内TG含量,减少FFA及甘油溢出的能力。与模型组细胞相比,高浓度FBREE(100μg/m L)处理的细胞中TG和FFA水平分别下降52.44%和37.83%。FBREE同时能减少模型细胞TNF-α和IL-6的分泌,高浓度FBREE(100μg/m L)分别抑制TNF-α(21.18%),IL-6(31.39%),MCP-1(40.09%)和CRP(41.73%) mRNA表达。此外,FBREE有效降低细胞中PPARγ,C/EBPα,SREBP1c,PTP1B,a P2和HSL的m RNA表达,上调GLUT-4m RNA表达。结果提示,FBREE能有效促3T3-L1脂肪细胞消耗葡萄糖,分解TG,减少FFA和甘油溢出;调控细胞糖、脂代谢来改善胰岛素抵抗,并降低胰岛素抵抗所致炎症水平的升高。     

白藜芦醇通过降低LYRM1 mRNA表达抑制3T3-L1前脂肪细胞增殖

目的：观察白藜芦醇（resveratrol,Res）对3T3-L1前脂肪细胞增殖活性的影响,并探讨其机制。方法：对3T3-L1前脂肪细胞进行培养,分别设置对照组以及25、50、75、100 μmol/L的Res干预组,噻唑蓝比色法观察不同剂量干预对细胞增殖活性的影响;实时荧光定量聚合酶链反应检测细胞中LYR Motif containing 1（LYRM1）基因mRNA的表达情况;Western blotting实验检测细胞中促凋亡蛋白Bak和抑凋亡蛋白Bcl-2的表达水平。结果：Res干预可使3T3-L1前脂肪细胞增殖活性降低;细胞中LYRM1 mRNA水平降低,Bak蛋白表达含量升高,Bcl-2蛋白表达含量降低,均具有剂量依赖效应。结论：Res可以抑制3T3-L1前脂肪细胞增殖,这可能与Res降低细胞内LYRM1 mRNA表达,影响线粒体功能并启动凋亡程序有关。     

异甘草素对3T3-L1前脂肪细胞分化的抑制作用

目的：考察异甘草素对3T3-L1前脂肪细胞分化的影响,探究其作用机制。方法：采用3T3-L1前脂肪细胞,利用磺酰罗丹明B（sulforhodamine B,SRB）法检测异甘草素对3T3-L1前脂肪细胞增殖的影响,采用传统的鸡尾酒法诱导3T3-L1细胞分化为脂肪细胞,利用油红O染色法检测分化细胞脂滴形成;采用实时荧光定量逆转录聚合酶链式反应方法,检测细胞CCAAT增强子结合蛋白（CCAAT-enhancer-binding proteins,C/EBP）亚型C/EBPα、C/EBPβ、脂肪酸合成酶（fatty acid synthetase,FAS）、脂肪分化相关蛋白adipophilin、过氧化物酶体增殖物激活受体γ（peroxisome proliferators activated receptor γ,PPARγ）、腺苷酸活化蛋白激酶（adenosine monophosphateactivated protein kinase,AMPK）的mRNA表达水平,Western blotting法检测AMPK蛋白磷酸化水平。结果：异甘草素可浓度依赖性地抑制3T3-L1细胞增殖,并明显抑制分化细胞内脂滴形成,同时抑制了细胞分化相关基因C/EBPα、C/EBPβ、FAS、adipophilin、PPARγ mRNA的表达,AMPK mRNA的表达未受影响,但异甘草素处理明显上调了AMPK蛋白的磷酸化水平。结论：异甘草素可抑制3T3-L1前脂肪细胞向脂肪细胞分化,其机制可能与活化AMPK信号通路相关。     

胰岛素诱导3T3-L1脂肪细胞胰岛素抵抗模型的建立

为建立胰岛素抵抗脂肪细胞模型,以3T3-L1前脂肪细胞为研究材料,通过3-异丁基-1-甲基黄嘌呤、地塞米松和胰岛素联合诱导其分化为3T3-L1脂肪细胞,通过葡萄糖消耗实验研究胰岛素诱导3T3-L1脂肪细胞产生胰岛素抵抗的作用浓度和时间关系,发现10-7mmol/L胰岛素诱导处理48h是3T3-L1脂肪细胞产生胰岛素抵抗的最适条件,该细胞模型的胰岛素抵抗状态可维持48h。通过高浓度胰岛素成功诱导3T3-L1脂肪细胞产生胰岛素抵抗,具有建模周期短、重复性好、操作简便的优点,该细胞模型可以用于抗胰岛素抵抗天然产物的筛选研究。     

小麦烷基间苯二酚对3T3-L1脂肪细胞胰岛素抵抗改善作用及机制

低度慢性炎症状态是肥胖导致机体胰岛素抵抗的重要原因之一.小麦烷基间苯二酚(alkylresorcinols,ARs)是全麦食品膳食的生物标记物和重要的活性功能成分.利用体外炎症因子诱导,建立3 T3-L1成熟脂肪细胞胰岛素抵抗模型,通过检测脂肪细胞脂质分解和葡萄糖吸收与利用情况,探讨小麦ARs在炎症状态下对脂肪细胞胰岛素抵抗的保护机制.研究结果表明:不同浓度小麦ARs(5～20μmol/L)干预能够剂量依赖性地改善炎症因子诱导的3T3-L1脂肪细胞胰岛素抵抗,脂肪细胞对葡萄糖利用率分别提升了4.3％、10.2％ 和24.0％;小麦ARs可以显著缓解炎症因子导致的脂肪细胞脂质分解.进一步机制解析发现:炎症因子显著降低了脂肪细胞糖代谢两个关键蛋白Akt的磷酸化(p-Akt)及其下游GLUT4蛋白表达,导致其葡萄糖利用障碍,而ARs干预显著提升了这两个蛋白的表达;采用PI3K抑制剂(LY294002)预处理脂肪细胞后,ARs对于脂肪细胞p-Akt及GLUT4表达的增加被抑制,相应的对于葡萄糖吸收的改善作用也被显著降低,脂肪细胞脂质分解增加,表明ARs通过特异性激活p-Akt/GLUT4信号通路改善了3 T3-L1脂肪细胞胰岛素抵抗.最后,研究了小麦ARs的5种主要单体成分分别对于脂肪细胞胰岛素抵抗的改善作用,结果表明,十七烷基间苯二酚是小麦ARs发挥生理功能的主要活性物质.     

Inhibitory effects of garcinol and pterostilbene on cell proliferation and adipogenesis in 3T3-L1 cells

The aim of this work was to study the effects of garcinol and pterostilbene on cell proliferation and adipogenesis in 3T3-L1 cells. The results showed that garcinol and pterostilbene decreased the cell population growth and caused cell cycle arrest at the G2/M phase in 3T3-L1 preadipocytes. During adipocyte differentiation, both garcinol and pterostilbene had inhibitory effects on fat droplet formation and triacylglycerol accumulation. The data indicated that garcinol and pterostilbene could inhibit the glycerol-3-phosphate dehydrogenase (GPDH) activity by 97.8 and 61.5%, respectively, as compared to the control. Both garcinol and pterostilbene significantly attenuated the protein expressions of PPARγ and C/EBPα during 3T3-L1 adipocyte differentiation. Moreover, garcinol and pterostilbene caused an inhibition of lipid accumulation in the 3T3-L1 adipocyte differentiation phase. Garcinol and pterostilbene also significantly up-regulated the gene expression of adiponectin as well as down-regulated the gene expressions of leptin, resistin, and fatty acid synthase (FAS) in 3T3-L1 adipocyte differentiation. In 3T3-L1 adipocytes, garcinol significantly down-regulated the protein expressions of PPARγ and FAS as well as up-regulated the protein expressions of adipose triglyceride lipase (ATGL) and adiponectin. Garcinol also significantly up-regulated the gene expression of adiponectin as well as down-regulated the gene expressions of leptin and FAS. These results suggest that garcinol and pterostilbene have anti-adipogenic effects on preadipocytes and adipocytes.     

酵母菌葡萄糖耐量因子的纯化

以高铬酵母菌粉为研究对象,采用温和的纯化方法,通过氨水提取高铬酵母菌粉中的酵母菌葡萄糖耐量因子（glucose tolerance factor,GTF）,联用SuperdexTM75和Sephadex G25凝胶过滤层析对提取物进行粗分离,然后用反相高效液相色谱对提取物进行再分离,从而对GTF进行高效纯化研究。将GTF纯化品作用于胰岛素抵抗型3T3-L1脂肪细胞,通过检测细胞葡萄糖消耗量,分析GTF纯化品对细胞葡萄糖代谢调节活性。研究表明,GTF纯化品可以有效提高胰岛素抵抗型3T3-L1脂肪细胞葡萄糖的消耗。可见,经过多步柱层析纯化后,可以得到具有葡萄糖代谢调节活性的GTF纯化品 。     

Ankaflavin regulates adipocyte function and attenuates hyperglycemia caused by high-fat diet via PPAR-γ activation

The effects of ankaflavin (AK) on adipokines level and insulin sensitivity were investigated. Mice were fed with high-fat diet (HFD) and AK to evaluate hyperglycemia and hyperlipidemia. Additionally, mature differentiated 3T3-L1 adipocytes were treated with AK or monascin (MS) to determine insulin signaling. Results showed that AK down-regulated serum and hepatic triacylglyceride (TG) and total cholesterol (TC) levels in mice, ameliorating hyperglycemia and hyperinsulinemia symptoms elicited by the HFD. AK elevated serum adiponectin levels in HFD-induced mice and mature 3T3-L1 adipocytes. The effect of AK on insulin sensitivity and adipokines secretion were abolished by peroxisome proliferator activated receptor-γ PPAR-γ antagonist GW9662. Moreover, we made the novel discovery that AK markedly promoted insulin receptor and Akt phosphorylation, and increased glucose uptake in mature 3T3-L1 adipocytes to a greater extent than did MS. Taken together, AK attenuated insulin resistance in HFD-induced mice and promoted insulin sensitivity in 3T3-L1 adipocytes through PPAR-γ activation.     

Cinnamon water extracts increase glucose uptake but inhibit adiponectin secretion in 3T3-L1 adipose cells

The effects of three concentrations (0.2, 0.3, and 0.4 mg/mL) of a cinnamon extract (CE) (Cinnamomum zeylanicum) on glucose uptake and adiponectin secretion in 3T3-L1 adipocytes were examined in the presence and absence of 0.5 nM and 50 nM insulin. In the absence of insulin, adipocytes exposed to 0.2 mg/mL CE showed an approximate two-fold increase in glucose uptake relative to controls although glucose uptake was unaffected by the two higher concentrations of CE. No effect of CE on glucose uptake was noted in the presence of 0.5 nM insulin whereas the two highest concentrations (0.3 and 0.4 mg/mL) of CE showed a significant dose-dependent decrease in glucose uptake in the presence of 50 nM insulin. Treatment of the adipocytes with 50 nM wortmannin, an irreversible inhibitor of the p110 isoform of phosphoinositide 3'-kinase, was associated with complete inhibition of the stimulated glucose uptake induced by 0.2 mg/mL CE. Treatment of the adipocytes with 0.2 mg/mL CE was associated with an inhibition of adiponectin secretion to levels that were nondetectable. The present study indicates that although 0.2 mg/mL CE has insulin-mimetic action in 3T3-adipocytes in terms of glucose uptake, secretion of the antidiabetic hormone adiponectin is adversely affected.