共轭亚油酸诱导人乳腺癌细胞(MCF-7)凋亡的作用

目的　为了研究共轭亚油酸单体 (c9,t11 CLA)对人乳腺癌细胞 (MCF 7)凋亡的影响。方法　采用细胞生长曲线 ,凋亡细胞的荧光显微镜和电镜观察、流式细胞光度术的检测以及p5 3蛋白表达的方法 ,观察了用不同浓度c9,t11 CLA(2 5、5 0、10 0和 2 0 0 μmol L)诱导MCF 7细胞凋亡作用。结果　c9,t11 CLA可明显抑制MCF 7细胞生长 ,8天的抑制率分别为 -6 0 %、4 5 2 %、99 0 %和 99 4 %。通过荧光显微镜和电镜技术观察到了发生凋亡的MCF 7细胞 ;用流式细胞光度术也检测到c9,t11 CLA可诱导MCF 7细胞产生凋亡 ,并随着c9,t11 CLA浓度的增加 ,细胞凋亡率逐渐增加 ;而p5 3蛋白表达则随着c9,t11 CLA浓度的增加呈现逐渐降低的趋势。结论　c9,t11 CLA可诱导MCF 7细胞产生凋亡 ,这可能是c9,t11 CLA抑制肿瘤细胞生长的机制之一。     

c9,t11-共轭亚油酸氧化稳定性的研究

目的：研究75％c9，t11-共轭亚油酸（c9，t11-CLA）在不同条件下的氧化稳定性，并在同等条件下与亚油酸（LA）进行比较，探讨影响75％c9，t11-CLA氧化稳定性的因素。方法：测定75％c9，t11-CLA和LA在暴露于空气、充氮保护、加入0．02％没食子酸丙酯、色拉油中及0．02％Ca^2＋存在条件下的过氧化值，同时进行气相色谱分析，观察5个不同时间75％c9，t11-CLA和IA含量的变化。结果：当75％c9，t11-CLA和LA在暴露于空气、充氮保护、加入0．02％没食子酸丙酯、色拉油中及0．02％Ca^2＋存在的条件下，75％c9，t11-CLA在不同处理条件下的氧化稳定性顺序为：0．02％没食子酸丙酯组〉充氮保护组〉色拉油组〉暴露于空气组〉0．02％Ca^2＋组（P〈0．05）。75％c9，t11-CLA的氧化速度快于亚油酸（IJA）的氧化速度（P〈0．05）。结论：0．02％没食子酸丙酯可明显提高c9，t11-CLA的氧化稳定性。增强c9，t11-CLA的稳定性已成为保护c9，t11-CLA有效生物活性的至关重要的因素。     

共轭亚油酸对正常动物细胞和人体肿瘤细胞间通讯功能的影响

为探讨c9,t11-共轭亚油酸 (CLA)的抑癌作用可能机制 ,在促癌物 (TPA)存在下 ,对正常细胞(CHL)以及人体肿瘤细胞 (SGC 790 1细胞和MCF 7细胞 )的细胞间隙连接通讯功能 (GJIC)的影响 ,采用划痕标记染料示踪技术 (SLDT) ;c9,t11 CLA剂量为 2 5 (mol L ,5 0 (mol L ,10 0 (mol L和 2 0 0 (mol L ,阴性对照为乙醇。结果显示 ,c9,t11 CLA可明显地提高TPA对CHL细胞的GJIC的抑制效应 ,当c9,t11 CLA浓度为 2 0 0 (mol L作用 48h时 ,细胞间隙通讯功能基本上与阴性对照组相近 ;当用c9,t11 CLA作用SGC 790 1细胞和MCF 7细胞2 4h和 48h时 ,可见 (2 4h 10 0 μmol L的MCF 7细胞 ) 2 4h 2 0 0 μmol L和 48h 10 0、2 0 0 μmol L剂量组的肿瘤细胞有一定的细胞间隙通讯功能。提示c9,t11 CLA可提高SGC 790 1细胞和MCF 7细胞的GJIC的功能 ,并且不同程度的拮抗TPA对CHL细胞GJIC的抑制效应     

Diet supplementation with the cis-9,trans-11 conjugated linoleic acid isomer affects the size of adipocytes in Wistar rats

Previous reports have demonstrated that conjugated linoleic acid (CLA) acts on body fat accumulation in a variety of animal models. The aim of the present study was to investigate the effect of cis (c)-9,trans (t)-11 and t10,c12 CLA isomers on the number and size of adipocytes from the inguinal and retroperitoneal fats in Wistar male rats. A 5.1% palm oil–based diet was supplemented with CLA isomers as follows: 0.6% of c9,t11, 0.6% of t10,c12, 1.3% of c9,t11 and t10,c12 isomers in mixture, and a control nonsupplemented group for comparative purposes. Fat tissues were prepared on microscope slides for histologic examination using an image-analysis software to count the number of adipocytes and measure cell sizes. The results showed that CLA isomers did not affect (P > .05) either final body and fat depot weights or serum lipids (with the exception of triacylglycerols) and adipocytokines (leptin and adiponectin). Animals fed the c9,t11 CLA isomer diet showed larger adipocytes when compared to other groups. Independently of the CLA dietary treatment, retroperitoneal fat showed larger adipocytes (3319 μm²) and therefore a smaller number of adipocytes per unit of area, compared to inguinal fat (3055 μm²). Taken together, the data suggest that a palm oil–based diet supplemented with the c9,t11 CLA isomer in Wistar rats, in contrast to the t10,c12 isomer and the mixture of both isomers, increases adipocyte dimensions in inguinal and retroperitoneal fat depots, while having a minor effect in serum lipids and adipocytokines.     

共轭亚油酸诱导人胃腺癌细胞(SGC-7901)凋亡的作用

目的 研究共轭亚油酸单体（c9,t11-CLA)诱导人体胃腺癌细胞（SGC－7901）凋亡作用。方法 采用细胞生长曲线,凋亡细胞的荧光显微镜、电镜观察,流式细胞光度术的检测以及P53蛋白表达方法。结果 显示出c9,t11-CLA对SGC－7901细胞有明显的抑制作用,并可诱导SGC－7901细胞产生凋亡,并随着c9,t11-CLA浓度的增加,细胞凋亡率逐渐增加;而P53蛋白表达则随着c9,t11-CLA浓度的增加呈逐渐降低的趋势。结论 这可能是c9,t11-CLA抑制肿瘤细胞机制之一。     

Isomer specificity of conjugated linoleic acid (CLA): 9E,11E-CLA

Conjugated linoleic acids (CLA) were identified in 1980''s, since then it has been intensively studied due to its various beneficial health effects such as anti-inflammatory, anti-atherogenic, anti-carcinogenic and anti-diabetic/obesity effects. Isomer specificity of a number of CLA isomers, especially predominant isomer 9Z,11E- and 10E,12Z-CLA, is now recognized. However, the less prevalent CLA isomers have not been well characterized. Recently, studies have reported the distinctively different effects of 9E,11E-CLA in colon cancer cells, endothelial cells, and macrophage cells compared to the rest of CLA isomers. In this review, various effects of CLAs, especially anti-inflammatory and anti-atherogenic effects, will be discussed with focusing on the isomer-specific effects and potential mechanism of action of CLA. At last, recent studies about 9E,11E-CLA in in vitro and animal models will be discussed.     

共轭亚油酸对人胃腺癌细胞侵袭能力的影响及其作用机制

研究c9,t11-共轭亚油酸 (CLA)对人胃腺癌细胞 (SGC 790 1)侵袭能力的影响 ,探讨其抑制肿瘤转移的可能机理。用 0、2 5、5 0、10 0和 2 0 0 μmol LCLA处理细胞 2 4h后 ,分别用重组基底膜侵袭实验评价癌细胞侵袭能力 ;PAGE底物酶谱方法检测Ⅳ型胶原酶活性 ;RT PCR方法检测SGC 790 1细胞TIMP 1和TIMP 2mR NA表达。研究结果表明 :c9,t11 CLA处理后 ,SGC 790 1细胞侵袭重组基底膜的能力下降、SGC 790 1细胞培养上清中的Ⅳ型胶原酶活性降低、SGC 790 1细胞中TIMP 1和TIMP 2mRNA的表达增加。因此 ,c9,t11 CLA抑制SGC 790 1细胞侵袭重组基底膜 ,并且c9,t11 CLA的抗侵袭活性与降低肿瘤细胞培养上清中Ⅳ型胶原酶活性和诱导肿瘤细胞TIMP 1和TIMP 2mRNA的表达等有关     

c9,t11-共轭亚油酸对巨噬细胞因子表达的影响

目的 研究c9，t11-共轭亚油酸(Conjugated linoleic acid，CLA)对C57小鼠巨噬细胞杀伤黑色索瘤细胞(B16-MB)能力的影响。方法用0，25，50，75，100μmol／L CLA处理巨噬细胞24h后，分别用MTT法检测CLA处理的巨噬细胞对B16-MB细胞的杀伤能力；RT-PCR方法检测C57小鼠巨噬细胞细胞因子IL-6、TNF-α和iNOS mRNA表达。结果 在100，75μmol／L CLA处理后，巨噬细胞对肿瘤的杀伤率分别为18％和14．5％：同时，IL-6、TNF-α和iNOS mRNA表达增加。结论 c9，tll-CLA增强C57小鼠巨噬细胞对B16-MB细胞的杀伤能力，并与其诱导IL-6、TNF-α和iNOS mRNA的表达有关。推测CLA发挥抗肿瘤作用可能与其参与机体免疫调节作用有关．     

Conjugated linoleic acid alters caveolae phospholipid fatty acid composition and decreases caveolin-1 expression in MCF-7 breast cancer cells

Conjugated linoleic acid (CLA) refers to a group of biologically active fatty acids that exhibit anticarcinogenic properties; however, the mechanism of action remains poorly understood. Caveolae are specialized plasma membrane structures that affect many facets of cancer cell function, including growth, cell signaling, and apoptosis. Therefore, one potential mechanism could be alteration of caveolae lipid composition and function. We hypothesized that CLA can alter the lipid microenvironment of caveolae and alter expression of the major caveolae-resident protein, caveolin-1. MCF-7 human breast cancer cells were treated with a vehicle control, linoleic acid (LA), or CLA for 3 days after which total cell lysate, plasma membrane, and caveolae membrane fractions were isolated. Our findings indicate that CLA readily incorporates into caveolae (Δ9cis,11trans-18:2 being the major isomer) and maybe preferentially enriched in specific phospholipid species. Furthermore, caveolin-1 localization to caveolae after treatment with CLA was decreased relative to either control- or LA-treated cells, without changes in total cellular levels of protein relative to vehicle-control treated cells. Taken together, our results suggest that further investigation of a potential therapeutic role for CLA in modulating caveolae function in breast cancer is merited.     

气相色谱分析法测定酸奶和奶油中c9,t11-共轭亚油酸的含量

目的：建立用程序升温气相色谱法测定奶制品中c9,t11-共轭亚油酸含量的方法。方法：首先建立本实验方法的气相色谱分析条件；采用内标法，将样品提取、甲酯化后，进行气相色谱分析；同时对实验方法的回收率、精密度也进行了分析。结果：能够将甲酯化亚油酸和c9,t11-共轭亚油酸很好地分离；内标物十七烷酸甲酯与其它脂肪酸甲酯能够完全分离，并不受样品中其它组分的影响；c9,t11-共轭亚油酸的含量分别为：帕玛拉特天然酸奶饮品10．78mg/g，万家宝原味酸奶（搅拌型）5．03mg/g，奶油22．54mg/g脂肪。实验方法的回收率为84．74％，RSD＝3．73％；精密度RSD＝2．58％。结论：所建立的实验条件准确可靠，这对于分析奶及奶制品来源的c9,t11-共轭亚油酸含量具有指导意义。     

Quantitative determination of conjugated linoleic acid isomers by silver ion HPLC in ewe milk fat

The aim of this research was to validate a method for the quantification of conjugated linoleic acid (CLA) isomers in the fat of ewe's milk. The isomers in the form of methyl ester (FAME) are separated by silver ion high performance liquid chromatography (Ag⁺HPLC) and the quantification was based on the measurement of the integrated area under the 231 nm peaks, using external CLA reference standards. The response linearity is maintained in a wide range of concentrations and the quantification limit estimated was of 0.005 μg/injection for the cis-9,trans-11 and trans-10,cis-12 isomers. Referred to the samples this limit would be 0.008 mg/g of fat in the usual working conditions. In the precision assay an RSDr of 2.14% for the isomer cis-9,trans-11 was calculated and for the rest of the CLA isomers varied between 2.08 and 7.5%. The recovery assays were performed adding CLA cis-9,trans-11 triglyceride and the mean recovery was 96%. The method proposed allows the determination of the individual content of different CLA isomers using one single technique, HPLC and supposes saving time and resources.     

trans-11 18:1 Vaccenic Acid (TVA) Has a Direct Anti-Carcinogenic Effect on MCF-7 Human Mammary Adenocarcinoma Cells

Trans vaccenic acid (TVA; trans-11 18:1) is a positional and geometric isomer of oleic acid and it is the predominant trans isomer found in ruminant fats. TVA can be converted into cis-9, trans-11 conjugated linoleic acid (c9, t11-CLA), a CLA isomer that has many beneficial effects, by stearoyl CoA desaturase 1 (SCD1) in the mammary gland. The health benefits associated with CLA are well documented, but it is unclear whether trans fatty acids (TFAs) from ruminant products have healthy effects. Therefore, the effects of TVA on the proliferation of MCF-7 human breast adenocarcinoma cells and MCF-10A human breast epithelial cells were investigated in the present study. Results showed that TVA inhibited the proliferation of MCF-7 cells but not MCF-10A cells by down-regulating the expression of Bcl-2 as well as procaspase-9. In addition, the suppressive effect of TVA was confirmed in SCD1-depleted MCF-7 cells. Our results suggested that TVA exerts a direct anti-carcinogenic effect on MCF-7 cells. These findings provided a better understanding of the research on the anti-carcinogenic effects of TVA and this may facilitate the manufacture of TVA/c9, t11-CLA fortified ruminant products.     

共轭亚油酸对人胃腺癌细胞中环氧合酶的影响

目的采用体外细胞培养方法,研究不同浓度c9,t11-共轭亚油酸(CLA)对人胃腺癌细胞(SGC-7901)的亚油酸代谢途径中限速酶-环氧合酶(COX)表达的影响.方法采用逆转录聚合酶链反应(RT-PCR)和蛋白免疫印迹(Western blot)方法检测不同浓度c9,t11-CLA处理后的SGC-7901细胞中环氧合酶(COX)-1、(COX)-2mRNA和蛋白的表达.结果在200,100,50和25μmol/L浓度时,c9,t11-CLA均可下调COX-2 mRNA和蛋白的表达,与共轭亚油酸(CLA)浓度呈负相关;上调COX-1 mRNA的表达,并与CLA浓度呈正相关.结论 c9,t11-CLA的抗癌活性与其影响COX的表达有关.     

环氧合酶-2在c9,t11-共轭亚油酸抑制肿瘤细胞转移中的作用

目的 研究c9,t11-共轭亚油酸（c9,t11-CLA）抑制人胃腺癌细胞（SGC-7901）转移作用与亚油酸代谢途径中限速酶环氧合酶-2（COX-2）的关系。方法采用体外细胞培养方法,用COX-2的选择性抑制剂NS．398抑制SGC-7901细胞中COX-2的活性,再加入200、100、50和25μmol／L浓度的c9,t11-CLA,利用重组基底膜侵袭实验、黏附实验、趋向运动实验检测c9,t11-CLA抑制肿瘤细胞转移的作用与COX-2的关系。结果与NS-398组比较,NS-398＋100Ixmol／Lc9,t11-CLA和NS-398＋200μmol／L c9,t11-CLA对SGC-7901细胞的侵袭有明显的抑制作用,穿过膜的细胞数分别为48．7±1．5（F=14．309,P=0．000）和43．7±4．0（F=19．005,P=0．000）;NS-398＋200μmol／L c9,t11-CLA组能显著降低SGC-7901细胞对基质成分层粘连蛋白、纤维粘连蛋白和基质胶的黏附作用,所测吸光度值（A值）分别为0．052±0．011,0．058±0．008（F=3．063,P=0．021）和0．042±0．004（F=6．692,P=0．001;F=11．999,P=0．000）;NS-398＋200ixmol／L c9,t11-CLA对SGC-7901细胞的趋向运动能力无明显的抑制作用（F=1．380,P=0．276）,其中NS-398＋2001xmol／L c9,t11-CLA组细胞数为26．6±3．4。结论 c9,t11-CLA具有抑制SGC-7901细胞体外侵袭能力、黏附能力和趋向运动能力,这种抑制作用可能与COX-2途径有关。     

Conjugated linoleic acid is related to bone mineral density but does not affect parathyroid hormone in men

The relationships between conjugated linoleic acid (CLA) status, bone, body composition, and the effect of CLA on calciotropic hormones are unclear. A cross-sectional study was designed to examine the association between c9, t11 CLA status in erythrocyte membranes (RBC) and body composition. This preceded a dose-response trial investigating if c9, t11 CLA affected parathyroid hormone (PTH). It was hypothesized that (1) higher c9, t11 CLA status in RBC will be associated with a lower fat and higher bone mass and that (2) PTH will be reduced by 30% after supplementation of c9, t11 CLA. Fifty-four men (age, 19-53 years) were included in the cross-sectional analysis, of which 31 were studied in the dose-response trial and randomized to 1 of 3 groups: placebo (n = 10), 1.5 g/d (n = 11), or 3.0 g/d (n = 10) of c9, t11 CLA for 16 weeks. Men with RBC c9, t11 CLA status above the median had higher whole body bone mineral density (BMD) (1.359 ± 0.024 vs 1.287 ± 0.023 g/cm²; P = .04) and whole body lean mass (WBL) percentage (78.8% ± 0.9% vs 75.3% ± 1.0%; P = .01), whereas body mass index (24.8 ± 0.5 kg/m² vs 27.3 ± 0.9 kg/m²; P = .01) and whole body fat mass percentage (17.3% ± 0.9% vs 21.3% ± 1.1%; P = .007) were lower. In regression analysis, RBC c9, t11 CLA status accounted for a significant proportion (r² = 0.10) of the variation in whole body BMD (P = .03). There were no time or treatment differences among any bone or biomarkers of bone metabolism including PTH. These findings indicate that RBC c9, t11 CLA status, a reflection of long-term (~4 months) dietary CLA intake, positively relates to BMD. However, c9, t11 CLA supplementation does not appear to affect PTH in healthy men.