表没食子儿茶素没食子酸酯对高脂饮食大鼠脂肪组织TNF-α表达的影响及意义

目的 探讨表没食子儿茶素没食子酸酯（EGCG）对高脂饮食大鼠脂肪组织中肿瘤坏死因子-α（TNF-α）表达的影响及其与胰岛素敏感性的相关性.方法 将30只SPF级雄性SD大鼠随机分为正常饮食组（ND组,n=10）和高脂饮食组（HFD组,n=20）.喂养16w,当两组大鼠体质量出现显著差异后（P〈0.05）,将HFD组按随机区组原则分为单纯高脂组（HFD组,n=10）和EGCG干预组（HFD＋0.32%EGCG,EGCG组,n=10）.干预16w.留取血清及附睾周脂肪组织.检测每组大鼠空腹血糖（FBG）、胰岛素水平（FINS）及游离脂肪酸（FFAs）,并计算胰岛素抵抗指数（HOMA-IR）;应用Real-time PCR及Western blot方法检测附睾周脂肪组织中TNF-α表达水平.结果 （1）与HFD组相比,EGCG组FINS水平显著下降[分别为（13.83±0.79）mIU/l vs.（31.71±3.61）mIU/l,P〈0.05];HOMA-IR值下降[分别为（3.36±0.31） vs.（7.59±0.99）,P〈0.05];FFAs值亦明显下降[分别为（0.38±0.08）mmol/l vs.（0.81±0.11）mmol/l,P〈0.05];三组大鼠FBG水平无明显统计学差异（P〉0.05）.（2）与ND组相比,HFD组脂肪组织中TNF-αmRNA水平显著升高[分别为（0.0033±0.00070）vs.（0.0010±0.00008）,P〈0.01];而EGCG组较HFD组则明显下降[分别为（0.0018±0.00037）vs.（0.0033±0.00070）,P〈0.05];同时,EGCG组TNF-α蛋白表达量低于HFD组[分别为（0.42±0.09）vs.（0.67±0.09）,P〈0.05];（3）EGCG组与ND组无明显差异（P〉0.05）.结论 EGCG改善高脂饮食大鼠胰岛素敏感性可能与减轻脂肪组织TNF-α介导的炎症状态相关.     

表没食子儿茶素没食子酸酯抑制肥胖大鼠肝中TLR4炎症通路及胰岛素抵抗

目的探讨表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)对肥胖大鼠肝组织中Toll样受体4(Toll-like receptor 4,TLR4)炎症通路以及胰岛素抵抗的影响。方法将30只雄性SD大鼠随机分为普食组(NC)和高脂饮食组(HFD)。喂养16周后,将高脂饮食组随机分为HFD组与EGCG组继续喂养16周,检测相关代谢指标,测定肝组织甘油三酯含量,并进行油红染色评估肝脂质聚集情况;实时荧光定量PCR检测其肝脏中TLR4和TNF受体相关因子6(TNF receptor associated factor 6,TRAF6)mRNA水平;蛋白质印记检测其肝组织中TLR4信号通路及胰岛素信号通路相关蛋白水平。结果EGCG明显降低大鼠肝脏甘油三酯浓度及脂质聚集、TLR4和TRAF6 mRNA水平,TLR4信号通路相关蛋白水平及胰岛素信号通路相关蛋白水平。结论EGCG抑制肥胖大鼠肝组织中TLR4通路以及胰岛素抵抗。     

表没食子儿茶素没食子酸酯抗流感作用的研究进展

茶叶的饮用历史已有千年,其保健功效得到广泛关注。表没食子儿茶素没食子酸酯(EGCG)是茶叶提取物中含量最高、活性最强的单体,研究表明EGCG具有显著的抗流感病毒活性。因其来源丰富、价格低廉、且无耐药,是抗流感药物的有利候选。本文首次针对EGCG的抗流感机制进行综述,全面评价EGCG的抗流感价值,为后续进一步开发EGCG类抗流感药物提供参考。     

表没食子儿茶素没食子酸酯对大鼠胰岛素抵抗的影响

目的研究表没食子儿茶素没食子酸酯（EGCG）对自发性2型糖尿病GK大鼠的胰岛素抵抗的影响及作用机制。方法 自发性2型糖尿病GK大鼠40只,同系健康对照Wistar大鼠10只,大鼠随机分为：正常对照组、2型糖尿病对照组、2型糖尿病低剂量EGCG（50 mg/kg）治疗组、中剂量（100 mg/kg）组、高剂量EGCG（300 mg/kg）组。干预6周后,分别检测葡萄糖耐量试验、胰岛素耐受试验、肝脏GcK、G6P以及PEPCKmRNA表达情况,以及骨骼肌细胞膜GLUT4含量的变化。结果各剂量治疗组的糖耐量均得到明显改善（P〈0.05）,胰岛素耐量在240 min时较模型对照组有明显差异（P〈0.05）。与模型组比较,低剂量和中剂量治疗组均能提高肝脏葡萄糖激酶（GcK）mRNA的表达（P〈0.05）,同时抑制葡萄糖-6-磷酸酶（G6P）和磷酸烯醇式丙酮酸激酶（PEPCK）mRNA的表达（P〈0.05）;高剂量治疗组肝脏三类酶mRNA的表达与模型对照组相比无明显差异。各剂量治疗组GK大鼠的骨骼肌细胞膜GLUT4的含量较模型对照组均具有明显上调（P〈0.05）。结论中低剂量EGCG可以改善GK大鼠胰岛素抵抗,其作用机制可能与抑制肝脏糖异生作用以及骨骼肌GLUT4的转位水平有关,并且EGCG具有代偿胰岛素的作用。     

表没食子儿茶素-3-没食子酸酯抑制TNF-α和IL-β在小鼠皮肤烫伤修复期间的表达

肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)和白细胞介素-1β(interleukin-1β,IL-1β)在创伤修复中起着至关重要的作用.本研究利用小鼠皮肤深II度烫伤模型,采用逆转录聚合酶链反应(RT-PCR)和酶联免疫吸附试验(ELISA)检测烫伤部位组织Tnf-αmRNA和Il-1βmRNA的表达水平以及TNF-α和IL-1β的含量,探讨表没食子儿茶素-3-没食子酸酯(EGCG)对小鼠皮肤烫伤修复期间TNF-α和IL-1β表达的影响.结果显示,用0.2 mg/g EGCG膏剂涂敷烫伤皮肤,处理12 h可致组织Tnf-αmRNA表达水平和TNF-α含量下降,处理24 h可致组织Il-1βmRNA表达水平和IL-1β含量下降.上述结果提示,0.2 mg/g EGCG处理能抑制烫伤组织TNF-α和IL-1β的表达,减弱创伤组织的炎症反应,有助于创伤组织的修复.     

表没食子儿茶素没食子酸酯对细胞信号转导通路的影响

表没食子儿茶素没食子酸酯（epigallocatechin-3-gallate,EGCG）是绿茶中含量最丰富的儿茶素,具有抗氧化、抗炎、抗动脉粥样硬化、抗癌等多种作用。研究发现EGCG通过多条细胞信号转导通路发挥作用。本文简要综述EGCG对MAPK、NF-κB、PI3K/Akt、JAK/STAT、TGF-β/Smad、Wnt/β-catenin等多条信号转导通路的影响。     

表没食子儿茶素-3-没食子酸酯抑制脂多糖诱导的巨噬细胞促炎因子TNF-α和IL-1β基因表达

表没食子儿茶素-3-没食子酸酯(epigallocatechin-3-gallate,EGCG)具有抗氧化、抗癌、抗炎等多种生物学特性,但对巨噬细胞中表达TNF-α及IL-1β的报告尚存在争议.本文旨在探索EGCG对脂多糖(LPS)诱导的小鼠腹腔巨噬细胞和RAW264.7细胞促炎细胞因子Tnf-α和Il-1β基因表达的影响.MTT结果显示,0~100μmol/L EGCG对RAW264.7细胞活力没有影响;实时荧光定量PCR(qRT-PCR)和ELISA分析显示,1 mg/L LPS可显著升高小鼠腹腔巨噬细胞和RAW264.7细胞Tnf-α和Il-1βmRNA和蛋白水平,EGCG单独处理对巨噬细胞Tnf-α和Il-1β的基因表达与蛋白生成没有影响,但可以抑制LPS诱导的巨噬细胞Tnf-α和Il-1β的基因表达与蛋白生成,并存在剂量依赖效应.上述结果提示,EGCG可以剂量依赖方式抑制LPS诱导的巨噬细胞促炎细胞因子Tnf-α和Il-1β的表达,这可能与EGCG的抗炎效应有关.     

表没食子儿茶素没食子酸酯抑制乳腺癌细胞增殖和迁移

表没食子儿茶素没食子酸酯（epigallocatechin-3-gallate, EGCG）是茶叶活性物质主要成分.EGCG可预防或治疗多种肿瘤.本文旨在探讨EGCG对人乳腺癌MDA-MB-231细胞增殖、凋亡及迁移力的作用及其机制. 经EGCG处理后,通过流式细胞术及噻唑蓝（MTT）法发现,EGCG使MDA-MB-231细胞周期阻滞,细胞凋亡数量上升,明显抑制乳腺癌细胞的存活率. EGCG处理后,MDA-MB-231细胞的形态由正常的纤维状变为鹅卵石状. 免疫荧光染色及免疫印迹结果表明,其上皮细胞标志物表达量增加,而间质标志物表达量下降. 通过划痕实验发现,EGCG明显抑制了细胞迁移能力. 本文揭示了EGCG通过抑制乳腺癌MDA-MB-231细胞周期进程,促进间质-上皮转化,抑制乳腺癌细胞增殖和迁移.     

茶树表没食子儿茶素-3-O-(3-O-甲基)没食子酸酯研究进展

表没食子儿茶素-3-O-(3-O-甲基)没食子酸酯(EGCG3"Me)是茶叶中最常检测到的甲基化表没食子儿茶素没食子酸酯(EGCG"Me),具有较表没食子儿茶素没食子酸酯(EGCG)更好的保健功效。本文对EGCG3"Me的理化性质、制备方法、保健功效、茶树EGCG3"Me含量影响因素、EGCG3"Me体内合成路径等国内外研究现状进行了综述,展望EGCG3"Me的体内代谢途径及其深加工产品研发将成为研究热点。     

表没食子儿茶素没食子酸酯对活性氧的抑制作用

生物体内的活性氧(Reactive oxygen species,ROS)过量引起氧化应激将导致脂质、DNA和蛋白质氧化损伤,从而引发一系列生理和病理反应。绿茶中茶多酚的主要成分表没食子儿茶素没食子酸酯((-)-Epigallocatechin-3-gallate,EGCG)具有强抗氧化性,能有效抑制ROS。本文简要介绍了生物体内ROS的来源和EGCG的特性及其对ROS的抑制作用。通过检测玫瑰红水溶液在光敏化时所产生~1O_2的1 270 nm近红外发光,分析比较了EGCG和迭代钠(NaN_3)对~1O_2发光的淬灭过程,发现EGCG对~1O_2的淬灭效果比NaN_3更好,为EGCG淬灭~1O_2的定量研究提供理论依据。     

Expression of TNF-α Gene in Anabaena sp. PCC 7120 and Purification of Its Product by Affinity Chromatography

The effects of N (NaNO3) and C (NaAc) source in medium on the expression of tumor necrosis factor-α (TNF-α) gene in transgenic Anabaena sp. PCC 7120 were compared. The data showed that N source stabilized the expression of foreign protein and C source altered the synthesis of cell walls. Comparing several methods for breaking the cells, supersonic was able to extract TNF-α better than others. For purification of TNF-α, transgenic Anabaena cells were broken, the extracts were precipitated with ammonia sulfate, and the impure TNF-α was eluted from DEAE ion exchange chromatography. Electrophoresis (PAGE-SDS) showed a single band at 17 kD position.     

大肠埃希菌脂多糖对高脂饮食动物血脂及炎性反应的影响

目的研究大肠埃希菌脂多糖对高脂饮食兔血脂和炎性反应的影响。方法给含0．5％胆固醇的饲料,3周后,分别在第4、8、12周采用耳动脉内、颈部、腹股沟处肌肉注射大肠埃希菌脂多糖（LPS）,并设立正常组和单纯高脂组。16周后观察兔的一般状态,取血清检查血脂六项、C-反应蛋白和TNF—α,取耳动脉、颈动脉、主动脉弓、胸主动脉、腹主动脉、髂动脉、肝脏,放置4％多聚甲醛中过夜,常规行HE染色,检查血管病变和相关脏器病变情况。结果单纯高脂组血清中胆固醇和LDL-C较正常组增加,复合模型组动物血清中胆固醇和LDL-C均明显高于单纯高脂组,单纯高脂组TNF-α较正常组高,复合模型组TNF-α比单纯高脂组高。病理显示主动脉弓变化明显,复合模型组内膜斑块弥漫,而单纯高脂组内膜只出现单个小斑块,单纯高脂组和复合模型组心脏病变区别不大,均见轻度水肿和小脂肪滴;单纯模型组肝脏细胞轻度水肿,而复合模型组肝脏脂肪滴明显。结论大肠埃希菌脂多糖加重了内膜斑块的形成,加剧了血脂代谢的紊乱和炎性反应。     

Tomato extract suppresses the production of proinflammatory mediators induced by interaction between adipocytes and macrophages

Obese adipose tissue is characterized by enhanced macrophage infiltration. A loop involving monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-α (TNFα) between adipocytes and macrophages establishes a vicious cycle that augments inflammatory changes and insulin resistance in obese adipose tissue. Tomatoes, one of the most popular crops worldwide, contain many beneficial phytochemicals that improve obesity-related diseases such as diabetes. Some of them have also been reported to have anti-inflammatory properties. In this study, we focused on the potential protective effects of phytochemicals in tomatoes on inflammation. We screened fractions of tomato extract using nitric oxide (NO) assay in lipopolysaccharide (LPS)-stimulated RAW264 macrophages. One fraction, RF52, significantly inhibited NO production in LPS-stimulated RAW264 macrophages. Furthermore, RF52 significantly decreased MCP-1 and TNFα productions. The coculture of 3T3-L1 adipocytes and RAW264 macrophages markedly enhanced MCP-1, TNFα, and NO productions compared with the control cultures; however, the treatment with RF52 inhibited the production of these proinflammatory mediators. These results suggest that RF52 from tomatoes may have the potential to suppress inflammation by inhibiting the production of NO or proinflammatory cytokines during the interaction between adipocytes and macrophages.     

The role of TNF-alpha in chronic inflammatory conditions, intermediary metabolism, and cardiovascular risk

The recent insight that inflammation contributes to the development of atherosclerosis and type 2 diabetes mellitus constitutes a major breakthrough in understanding the mechanisms underlying these conditions. In addition, it opens the way for new therapeutic approaches that might eventually decrease the prevalence of these public health problems. Tumor necrosis factor-alpha (TNF-alpha) has been shown to play a key role in these processes and thus might be a potential therapeutic target. Increased concentrations of TNF-alpha are found in acute and chronic inflammatory conditions (e.g., trauma, sepsis, infection, rheumatoid arthritis), in which a shift toward a proatherogenic lipid profile and impaired glucose tolerance occurs. Although therapeutic blockade of TNF-alpha worsens the prognosis in patients with abscesses and granulomatous infections, this strategy is highly beneficial in the case of chronic inflammatory conditions, including rheumatoid arthritis. Current investigations assessing the impact of anti-TNF agents on intermediary metabolism suggest that TNF-alpha blockade may improve insulin resistance and lipid profiles in patients with chronic inflammatory diseases.     

Impact of physical exercise on visceral adipose tissue fatty acid profile and inflammation in response to a high-fat diet regimen

PurposeStudies associate specific fatty-acids (FA) with the pathophysiology of inflammation. We aimed to analyze the impact of exercise on adipose tissue FA profile in response to a high-fat diet (HFD) and to ascertain whether these exercise-induced changes in specific FA have repercussions on obesity-related inflammation.MethodsSprague-Dawley rats were assigned into sedentary, voluntary physical-activity (VPA) and endurance training (ET) groups fed a standard (S, 35kcal% fat) or high-fat (71kcal% fat) diets. VPA-animals had unrestricted access to wheel-running. After 9-wks, ET-animals engaged a running protocol for 8-wks, while maintained dietary treatments. The FA content in epididymal white-adipose tissue (eWAT) triglycerides was analyzed by gas-chromatography and the expression of inflammatory markers was determined using RT-qPCR, Western and slot blotting.ResultsEight-wks of ET reversed obesity-related anatomical features. HFD increased plasma tumor necrosis factor (TNF)-α content and eWAT monocyte chemoattractant protein (MCP)-1 protein expression. HFD decreased eWAT content of saturated FA and monounsaturated FA, while increased linoleic acid and prostaglandin E2 (PGE2) levels in eWAT. VPA decreased visceral adiposity, adipocyte size and MCP-1 in HFD-fed animals. The VPA and ET interventions diminished palmitoleic acid and increased linoleic acid in HFD-fed groups. Moreover, both interventions increased PGE2 levels in standard diet-fed groups and decreased in HFD. ET increased eWAT fatty acid desaturase 1 (FADS1) and elongase 5 (ELOVL5) protein content in both diet types. ET reduced eWAT inflammatory markers (TNF-α, IL-6), macrophage recruitment (MCP-1 and F4/80) and increased IL-10/TNF-α ratio in plasma and in eWAT in both diet types.ConclusionsExercise induced FA-specific changes independently of dietary FA composition, but only ET attenuated the inflammatory response in VAT of HFD-fed rats. Moreover, the exercise-induced FA changes did not correlate with the inflammatory response in VAT of rats submitted to HFD.     

Dietary Supplementation with Epigallocatechin Gallate Elevates Levels of Circulating Adiponectin in Non-Obese Type-2 Diabetic Goto-Kakizaki Rats

Epigallocatechin gallate (EGCG) reportedly enhances plasma adiponectin levels in models of insulin resistance and obesity. In this study, we found that EGCG increases plasma adiponectin levels and decreases plasma triacylglycerol levels in non-obese diabetic Goto-Kakizaki rats with insulin secretory dysfunction. These results suggest that EGCG ameliorates lipid metabolic abnormality even in non-obese rats, probably by increasing adiponectin production.     

Induction of Multiple Cytokine Secretion from RAW264.7 Cells by Alginate Oligosaccharides

We investigated the cytokine-inducing activities of guluronate (G3–G6) and mannuronate (M3–M6) oligomers on RAW264.7 cells with the Bio-Plex assay system. Relatively high levels of tumor necrosis factor-α (TNF-α), granulocyte colony-stimulating factor (G-CSF), monocyte chemoattractant protein-1 (MCP-1), regulated upon activation normal T cell expressed and secreted (RANTES), granulocyte macrophage (GM)-CSF, and eotaxin were induced by alginate oligomers to different extents depending on the oligomer structures, and low but significant levels of interleukin (IL)-1α, IL-1β, IL-6, IL-9, and IL-13 were also induced. Throughout all cytokines tested, M-oligomers tended to be more potent than G-oligomers in terms of cytokine induction, and this tendency was evident in differences between G3 and M3.     

Protein malnutrition mitigates the effects of a high-fat diet on glucose homeostasis in mice

Nutrient malnutrition, during the early stages of development, may facilitate the onset of metabolic diseases later in life. However, the consequences of nutritional insults, such as a high-fat diet (HFD) after protein restriction, are still controversial. We assessed overall glucose homeostasis and molecular markers of mitochondrial function in the gastrocnemius muscle of protein-restricted mice fed an HFD until early adulthood. Male C57BL/6 mice were fed a control (14% protein-control diet) or a protein-restricted (6% protein-restricted diet) diet for 6 weeks. Afterward, mice received an HFD or not for 8 weeks (mice fed a control diet and HFD [CH] and mice fed a protein-restricted diet and HFD [RH]). RH mice showed lower weight gain and fat accumulation and did not show an increase in fasting plasma glucose and insulin levels compared with CH mice. RH mice showed higher energy expenditure, increased citrate synthase, peroxisome-proliferator-activated receptor gamma coactivator 1-alpha protein content, and higher levels of malate and α-ketoglutarate compared with CH mice. Moreover, RH mice showed increased AMPc-dependent kinase and acetyl coenzyme-A (CoA) carboxylase phosphorylation, lower intramuscular triacylglycerol content, and similar malonyl-CoA levels. In conclusion, protein undernourishment after weaning does not potentiate fat accumulation and insulin resistance in adult young mice fed an HFD. This outcome seems to be associated with increased skeletal muscle mitochondrial oxidative capacity and reduced lipids accumulation.