Anti-obesity effect of sulfated glucosamine by AMPK signal pathway in 3T3-L1 adipocytes

In this study, we investigated the effect of sulfated glucosamine (SGlc) on adipogenesis of 3T3-L1 adipocytes during differentiation of preadipocytes into adipocytes by measuring lipid accumulation and adipogenesis related factors. Treatment with SGlc reduced the triglyceride content in Oil-Red O staining and enhanced glycerol secretion in adipocytes in a dose-dependent manner. In addition, SGlc induced the down-regulation of adipogenesis related factors and adipocyte specific gene promoters. Moreover, treatment of 3T3-L1 adipocytes with SGlc activated the phosphorylated adenosine monophosphate-activated protein kinase (AMPK) α and β along with their substrate, acetyl-CoA carboxylase (ACC). These results suggest that inhibitory effect of SGlc on adipocyte differentiation might be mediated through the up-regulation of AMPK pathway.     

吡格列酮对高胆固醇模型大鼠脂肪组织细胞中肿瘤坏死因子-α分泌及其mRNA表达的影响

目的:研究吡格列酮对高胆固醇模型大鼠脂肪组织细胞中肿瘤坏死因子-α(TNF-α)分泌及其mRNA表达的影响。方法:将30只高胆固醇饮食8周的大鼠随机分为高胆固醇组(n=15)和吡格列酮组(n=15),前者继续给予高胆固醇饮食,后者在此基础上加吡格列酮3mg.kg-1.d-1,连续4周;另设喂普通饲料12周的对照组(n=15)。处死大鼠并检测血脂、血清TNF-α水平及其mRNA表达等指标。另取正常脂肪细胞加入脂多糖和不同浓度的吡格列酮(0.1、1.0、10.0μmol.L-1)中,测定脂肪组织细胞中的TNF-α水平及其mRNA表达。结果:与高胆固醇组比较,吡格列酮组可明显降低血清TNF-α水平及减弱其mRNA表达,但对血糖和血脂水平几乎无影响。上述吡格列酮各浓度组可呈浓度依赖性抑制脂多糖诱导TNF-α分泌及其mRNA表达。结论:吡格列酮可降低高胆固醇模型大鼠血清和脂肪组织中TNF-α水平。     

改良人骨髓间充质干细胞分离方法提高细胞定向分化能力

目的 改良人骨髓间充质干细胞(hBM-MSCs)分离方法,提高细胞定向分化能力.方法 用密度梯度离心法从少量人骨髓中分离得到单个核细胞,贴壁培养3天后换液,实验组换液后72h内每隔12h更换新鲜培养液,传代时胰蛋白酶37℃作用2min后终止消化;对照组未经频繁换液,胰蛋白酶消化3min.镜下观察分离细胞的形态变化.用成骨、脂肪和软骨细胞诱导液诱导两组第3代(P3)细胞分化,碱性磷酸酶钙钴染色法、茜素红染色法和Von Kossa银染色法检测成骨细胞分化;油红O染色法检测脂肪细胞分化;阿尔新蓝染色法检测软骨细胞分化.结果 首次换液72h后,实验组与对照组相比,贴壁细胞数量较少但形态均一性高.不同染色结果显示:诱导分化成骨细胞14天时,实验组95%以上细胞分化,对照组为60%～70%;诱导分化脂肪细胞21天时,实验组50%～60%细胞分化,对照组为40%;诱导分化软骨细胞21天时,实验组90%以上细胞分化,对照组为60%～70%.结论 首次换液72h内频繁更换新鲜培养液和传代时缩短胰蛋白酶消化时间的方法能够提高hBM-MSCs的定向分化能力.     

Effects of arecoline on adipogenesis, lipolysis, and glucose uptake of adipocytes—A possible role of betel-quid chewing in metabolic syndrome

To investigate the possible involvement of betel-quid chewing in adipocyte dysfunction, we determined the effects of arecoline, a major alkaloid in areca nuts, on adipogenic differentiation (adipogenesis), lipolysis, and glucose uptake by fat cells. Using mouse 3T3-L1 preadipocytes, we showed that arecoline inhibited adipogenesis as determined by oil droplet formation and adipogenic marker gene expression. The effects of arecoline on lipolysis of differentiated 3T3-L1 adipocytes were determined by the glycerol release assay, indicating that arecoline induced lipolysis in an adenylyl cyclase-dependent manner. The diabetogenic effects of arecoline on differentiated 3T3-L1 adipocytes were evaluated by the glucose uptake assay, revealing that ≥ 300 µM arecoline significantly attenuated insulin-induced glucose uptake; however, no marked effect on basal glucose uptake was detected. Moreover, using 94 subjects that were randomly selected from a health check-up, we determined the association of betel-quid chewing with hyperlipidemia and its related risk factors. Hyperlipidemia frequency and serum triglyceride levels of betel-quid chewers were significantly higher than those of non-betel-quid chewers. In this study, we demonstrated that arecoline inhibits adipogenic differentiation, induces adenylyl cyclase-dependent lipolysis, and interferes with insulin-induced glucose uptake. Arecoline-induced fat cell dysfunction may lead to hyperlipidemia and hyperglycemia/insulin-resistance. These findings provide the first in vitro evidence of betel-quid chewing modulation of adipose cell metabolism that could contribute to the explanation of the association of this habit with metabolic syndrome disorders.     

成纤维细胞生长因子21的研究进展

随着2型糖尿病发病率的增加,寻找一种更加安全有效的治疗药物已成为全球关注的问题,成纤维细胞生长因子21(FGF21)的代谢调节功能与胰岛素类似,并在很多方面优于胰岛素,因此FGF21有望成为代替胰岛素治疗糖尿病的新药。FGF21在2型糖尿病的动物模型中有较强的作用,主要作用于脂肪组织和胰腺,可以改善与肥胖有关的高血糖和高血脂,并在饥饿和酮症时发挥关键的调控作用。     

烟酸对高脂血症兔脂肪细胞胆固醇流出和肝X受体表达的影响

目的探讨烟酸对高脂血症兔脂肪细胞胆固醇流出和肝X受体（LXR）α、过氧化物酶体增殖物激活受体（PPAR）γmRNA表达的影响。方法选取12只健康雄性新西兰兔给予高胆固醇饲料培养8周,建立高胆固醇兔模型后,随机分为高胆固醇组（继续饲以高胆固醇饲料6周,n=6）,烟酸治疗组（在饲以高胆固醇饲料的基础上给予烟酸缓释剂0．2g·kg^-1·d^-1,共6周,n=6）,另选普通饮食14周雄性新西兰兔（n=6）作为对照组。实验结束后,取皮下脂肪行脂肪细胞培养,用液体闪烁计数器检测细胞内胆固醇流出,运用逆转录聚合酶链反应检测LXRα mRNA的表达。此外,在体外观察不同浓度的烟酸缓释剂（0．25、0．5、1、2mmol／L）对健康雄性新西兰兔脂肪细胞LXRα、PPARγ mRNA的影响。结果高胆固醇组脂肪细胞胆固醇流出率（5．94±1．26）％明显低于正常对照组（12．68±1．31）％,烟酸治疗组脂肪细胞胆固醇流出升高明显（16．39±3．32）％,3组间比较差异有统计学意义。逆转录聚合酶链反应显示烟酸治疗组较高胆固醇组LXRα mRNA表达高,与胆固醇流出率呈正相关。体外实验亦显示,烟酸缓释剂呈浓度依赖性升高脂肪细胞LXRα、PPARγ mRNA的表达。结论烟酸增加高脂血症兔脂肪细胞LXRα mRNA的表达及细胞内胆固醇流出。     

睾酮对3T3-L1脂肪细胞促酰化蛋白受体及下游信号蛋白的影响

目的:观察睾酮对3T3-L1(前)脂肪细胞促酰化蛋白(ASP)受体C5L2-mRNA和细胞表面C5L2蛋白表达的影响,以及睾酮对3T3-L1(前)脂肪细胞Gαq/11,Gβ,p-PKCα和p-PKCζ蛋白以及ASP刺激的Gαq/11,Gβ,p-PKCα和p-PKCζ蛋白表达的影响。方法:体外培养3T3-L1细胞,诱导细胞分化,用不同浓度睾酮作用于3T3-L1(前)脂肪细胞,孵育过夜后收获细胞,采用RT-PCR和流式细胞仪检测ASP受体mRNA和蛋白表达情况;采用Western Blot法检测基础状态和ASP刺激的Gαq/11,Gβ,p-PKCα和p-PKCζ蛋白表达。结果:睾酮呈浓度依赖性均抑制3T3-L1成熟脂肪细胞C5L2-mRNA和蛋白的表达,10-6mol/L时mRNA和蛋白分别减少了60%(P<0.01)和27%(P<0.01)。但前脂肪细胞C5L2-mRNA和蛋白表达水平均无显著性差异。高浓度(10-6mol/L)睾酮在一定程度上抑制ASP刺激的成熟脂肪细胞Gαq/11,Gβ,p-PKCα和p-PKCζ的表达,分别减少了52%(P<0.05),27%(P>0.05),50%(P<0.01)和57%(P<0.05);在前脂肪细胞,ASP-C5L2下游信号分子Gαq/11,Gβ,p-PKCα和p-PKCζ表达无明显抑制作用。结论:睾酮抑制成熟脂肪细胞ASP信号分子表达,睾酮诱导ASP抵抗的发生机制与下调脂肪细胞表面ASP受体功能有关,与干扰ASP-C5L2信号转导途径有关。ASP抵抗参与了高睾酮引起的胰岛素抵抗状态的病理生理过程,ASP抵抗可能参与多囊卵巢综合征(PCOS)、肥胖症等多种疾病的病理生理过程。     

α-硫辛酸抑制IκB激酶β对胰岛细胞的影响

目的 探讨脂肪细胞对共培养体系中胰岛细胞炎症状态的影响,以及α-硫辛酸对抗胰岛细胞炎症反应的作用.方法 以单纯胰岛细胞培养为对照组、胰岛细胞-脂肪细胞共培养为实验组、胰岛细胞-脂肪细胞共培养加α-硫辛酸为干预组.以胰岛素释放试验比较胰岛细胞的功能,采用实时荧光PCR和Western印迹法检测细胞内IκB激酶(IKK)B的mRNA和蛋白水平.结果 实验组胰岛索释放试验的分泌指数明显低于对照组和干预组(1.0±0.1vs2.6±0.2和2.5±0.5,P<0.01).实时荧光PCR显示,实验组的IKKβ mRNA水平明显高于对照组和干预组(4.62±0.60 vs 1.00±0.46和2.25±O.75,P相似文献   

Age-related bone loss in the LOU/c rat model of healthy ageing

Inbred albino Louvain (LOU) rats are considered a model of healthy aging due to their increased longevity in the absence of obesity and with a low incidence of common age-related diseases. In this study, we characterized the bone phenotype of male and female LOU rats at 4, 20 and 27 months of age using quantitative micro computed tomographic (mCT) imaging, histology and biochemical analysis of circulating bone biomarkers. Bone quality and morphometry of the distal femora, assessed by mCT, was similar in male and female rats at 4 months of age and deteriorated over time. Histochemical staining of undecalcified bone showed a significant reduction in cortical and trabecular bone by 20 months of age. The reduction in mineralized tissue was accompanied by reduced numbers of osteoblasts and osteoclasts and a significant increase in marrow adiposity. Biochemical markers of bone turnover, C-telopeptide and osteocalcin, correlated with the age-related bone loss whereas the calciotropic hormones PTH and vitamin D remained unchanged over time. In summary, aged LOU rats exhibit low-turnover bone loss and marrow fat infiltration, which are the hallmarks of senile osteoporosis, and thus represent a novel model in which to study the molecular mechanisms leading to this disorder.     

腺苷酸激活蛋白激酶在脂肪组织中的作用

腺苷酸激活蛋白激酶（AMPK）是细胞和机体能量代谢的主要调节器。组织缺氧、低血糖、禁食和运动可以激活脂肪细胞中的AMPK。AMPK活化后能通过磷酸化下游信号分子,刺激能量生成途径（葡萄糖转运,脂肪酸氧化）关闭能量消耗的途径（脂肪、蛋白质、糖类的生成）。现在已经明确脂肪组织不仅是能量储存的场所,也在能量平衡以及其它很多过程中发挥作用。研究AMPK与脂肪组织的关系,将为AMPK作为防治肥胖的新靶点提供可靠的理论基础和应用依据。