运动对老年肥胖大鼠脂联素的影响

目的：探讨运动对老年肥胖大鼠内脏脂肪组织脂联素mRNA和蛋白质表达、血浆脂联素浓度及胰岛素抵抗的影响。方法：取雄性SD大鼠,鼠龄21 d,分青春期、壮年期和老年期三个阶段喂养高脂饲料（脂肪率为36.3%~40.0%）,建立老年肥胖模型。鼠龄达到60周后,取自然生长老年大鼠随机分为对照组（C）和老年运动组（AE）,n=6;取老年肥胖大鼠随机分为肥胖对照组（OC）和肥胖运动组（OE）,n=6。动物跑台坡度0°,运动速度及时间为（15 m/min×15 min）,4组/次,组间休息5 min,每次共运动60 min,5次/周,持续运动8周。8周后,检测内脏脂肪组织脂联素mRNA和蛋白质表达,测定血糖、血浆脂联素浓度和胰岛素浓度,计算胰岛素抵抗。结果：运动干预后,与对照组比较,肥胖对照组大鼠脂联素mRNA和蛋白质表达显著减低,血糖浓度和胰岛素抵抗明显增高;而老年运动组大鼠脂联素mRNA和蛋白质表达显著增高。与肥胖对照组大鼠比较,肥胖运动组大鼠脂联素mRNA和蛋白质表达显著增高、血浆脂联素水平增高,血糖浓度和胰岛素抵抗明显减低。结论：老年肥胖大鼠内脏脂肪组织脂联素mRNA和蛋白质表达均降低,伴随胰岛素抵抗、血糖升高。运动能显著增加其内脏脂肪组织脂联素mRNA和蛋白质表达,升高血浆脂联素水平,改善胰岛素抵抗,降低血糖。     

替米沙坦对非酒精性脂肪肝大鼠肝组织PPARs及脂联素受体2表达的影响

目的探讨替米沙坦对非酒精性脂肪肝大鼠肝组织PPARs及脂联素受体2表达的影响。方法 40只雄性SD大鼠随机分为正常对照组(NC,n=15)、高脂对照组(FC,n=15)、高脂+替米沙坦干预组(FT,n=10)。NC组给予普通饲料,FC和FT组予高脂饲料喂养。12周末时随机取NC组和FC组各5只做正葡萄糖高胰岛素嵌夹实验和肝组织HE染色,确定造模成功后,FT组给予替米沙坦5 mg/(kg·d)灌胃,NC和FC组以等容量生理盐水灌胃,共4周。16周时应用高胰岛素正葡萄糖嵌夹实验技术稳态葡萄糖输注速率测定胰岛素敏感性,检测血清转氨酶、血脂及空腹血糖水平;应用逆转录聚合酶链反应法测定肝组织中过氧化物本酶体增殖活化受体(PPARs)、脂联素受体2(AdipoR2)和血管紧张素II 1型受体(AT1R)的表达。结果与NC组相比,FC组肝组织PPARα、PPARγ、AdipoR2 mRNA表达显著下降(P0.01),AT1R mRNA表达较NC组升高(P0.01);FT组PPARα、PPARγ、AdipoR2 mRNA表达较FC组升高(P0.01);FT组血清转氨酶、血脂及空腹血糖水平较FC组改善。结论替米沙坦能降低NASH大鼠的体重和肝指数,调节糖脂代谢并改善胰岛素抵抗状态,对NASH大鼠肝脏具有保护作用。     

高脂饮食诱导的C57BL/6J肥胖小鼠脂肪组织RIP140基因表达水平的研究(英文)

目的:探讨高脂饮食致肥胖小鼠脂肪组织RIP140mRNA表达水平的变化及其与胰岛素抵抗的关系。方法:将C57BL/6J雄性小鼠随机分为正常饮食(NFD)组、高脂饮食(HFD)组分别喂养14周后,测量两组小鼠体重,以NFD组小鼠体重作为对照,选取HFD组中体重大于对照组小鼠平均体重20%的小鼠作为肥胖组小鼠。对照组和肥胖组小鼠取血测甘油三酯(TG)、总胆固醇(TC)、空腹血糖(FBG)、空腹胰岛素水平(FIns),计算稳态模型胰岛素抵抗指数(HOMA-IR);采用RT-PCR技术检测两组小鼠附睾脂肪组织RIP140 mRNA的表达水平,并进行统计学分析。结果:HDF组小鼠中有12只符合标准计入肥胖组。肥胖组小鼠TG、TC、FBG、FIns(P0.05),HOMA-IR(P0.01)均明显高于对照组;肥胖组小鼠脂肪组织RIP140 mRNA的表达高于对照组,差异具有统计学意义(P0.05);相关分析显示小鼠脂肪组织RIP140 mRNA表达水平与TG水平呈正相关(r=0.536,P0.05),与胰岛素抵抗指数呈正相关(r=0.465,P0.05),而与TC、FBG、FIns水平相关分析无统计学意义(P0.05)。结论:高脂饮食诱导的肥胖小鼠脂肪组织RIP140 mRNA表达增加,并与胰岛素抵抗程度呈正相关。     

高脂饮食诱导的C57BL／6J肥胖小鼠脂肪组织RIP140基因表达水平的研究

目的：探讨高脂饮食致肥胖小鼠脂肪组织RIP140mRNA表达水平的变化及其与胰岛素抵抗的关系。方法：将C57BL／6J雄性小鼠随机分为正常饮食（NFD）组、高脂饮食（HFD）纽分别喂养14周后,测量两组小鼠体重,以NFD组小鼠体重作为对照,选取HFD组中体重大于对照组小鼠平均体重20％的小鼠作为肥胖组小鼠。对照组和肥胖组小鼠取血测甘油三酯（TG）、总胆固醇（TC）、空腹血糖（FBG）、空腹胰岛素水平（FIns）,计算稳态模型胰岛素抵抗指数（HOMA-IR）;采用RT—PCR技术检测两组小鼠附睾脂肪组织RIP140 mRNA的表达水平,并进行统计学分析。结果：HDF组小鼠中有12只符合标准计入肥胖组。肥胖组小鼠TG、TC、FBG、Fins（P〈0．05）,HOMA-1R（P〈0．01）均明显高于对照组;肥胖组小鼠脂肪组织RIP140mRNA的表达高于对照组,差异具有统计学意义（P〈0．05）;相关分析显示小鼠脂肪组织R1P140 mRNA表达水平与TG水平呈正相关（r=0．536,P〈0．05）,与胰岛素抵抗指数呈正相关（r=0．465,P〈0．05）,而与TC、FBG、Fins水平相关分析无统计学意义（P〉0．05）。结论：高脂饮食诱导的肥胖小鼠脂肪组织RIP140 mRNA表达增加,并与胰岛素抵抗程度呈正相关。     

Visfatin mRNA在PCOS患者网膜脂肪组织中的表达

目的：探讨visfatin基因在多囊卵巢综合征（PCOS）网膜脂肪组织中的表达及相关影响因素。方法：采用半定量RT-PCR方法检测PCOS组（30例）和对照组（25例）网膜脂肪组织visfatin mRNA表达,并测量体重指数、腰臀比、空腹血糖、空腹胰岛素、胰岛素抵抗指数和血清性激素水平。结果：①PCOS组网膜脂肪组织visfatin mRNA表达量高于对照组（P=0.000）。②网膜脂肪组织visfatin mRNA的表达量与BMI、WHR、FINS、HOMA-IR呈正相关（P〈0.05）。③多元逐步回归分析显示,HOMA-IR（P=0.000）和WHR（P=0.005）是影响网膜脂肪组织visfatin mRNA表达的相关因素。结论：网膜脂肪组织visfatin mRNA表达可能与PCOS胰岛素抵抗的发生和肥胖相关。     

黄芪水提取物减轻高脂饮食引起的小鼠肥胖

目的:研究黄芪水提取物(Astragalus radix extract,ARE)对高脂饮食(High fat diet,HFD)引起的小鼠肥胖的作用及可能机制。方法:将30只C57 BL/6小鼠随机分为正常喂养组(ND组,n=10)、高脂喂养组(HFD组,n=10)和高脂喂养+黄芪水提取物处理组(ARE组,n=10)。记录三组小鼠体重及食物摄入。在喂养16周时,对小鼠附睾白色脂肪称重,并进行HE染色观察脂肪细胞大小;对小鼠肝脏进行进行HE染色观察肝脏脂肪变性情况。应用ELISA方法检测血清瘦素及脂联素水平。应用Western Blot检测脂肪组织过氧化物酶体增殖物激活受体γ(Peroxisome proliferator activated receptorγ,PPARγ)表达。结果:1与ND组相比,HFD组体重及热量摄入均显著增加,表明肥胖模型建立成功;ARE处理组的体重较HFD组显著下降,但其热量摄入与HFD组相当。2与ND组相比,HFD组白色脂肪组织重量增加、脂肪细胞增大、肝细胞出现显著脂肪变性;ARE处理组上述指标较HFD组明显改善。3与ND组相比,HFD组瘦素水平升高、脂联素水平下降;ARE处理组与HFD组相比,瘦素水平降低、脂联素水平升高。4与ND组相比,HFD组PPARγ表达显著增加,而ARE处理组较HFD组PPARγ表达下降。结论:黄芪水提取物可能通过抑制PPARγ减轻高质饮食引起的肥胖。     

普洱茶提取物对单纯性肥胖大鼠MC4R基因表达的影响

为观察普洱茶提取物对高脂饮食诱导肥胖大鼠脂肪组织中黑皮素受体-4(MC4R)基因表达的影响,进一步探讨普洱茶抗肥胖的相关机制,本试验将大鼠随机分为正常对照组、高脂饲料组、高脂饲料+普洱茶提取物干预组,构建单纯性肥胖模型。每周测量大鼠体重,3个月试验结束后测量大鼠终末体重、脂肪组织重量,检测甘油三酯(TG)、总胆固醇(TC)、低密度脂蛋白(LDL-C)等血脂水平。提取大鼠附睾脂肪组织,采用实时荧光定量逆转录聚合酶链反应(RT-PCR)和免疫印迹试验(Western blot)检测肥胖相关基因MC4R mRNA和蛋白的表达水平。结果显示:普洱茶能显著减轻高脂饮食大鼠体重和脂肪组织重量,降低体脂比,并降低各项血脂水平;普洱茶提取物能显著上调MC4R基因和蛋白的表达。这表明普洱茶提取物具有减肥降脂作用,其分子机制可能与上调肥胖重要调节因子MC4R有关。     

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.     

Dll4蛋白在高脂饮食喂养大鼠脂肪组织炎症中的作用

目的 探讨Delta-like ligand 4（Dll4）蛋白在高脂饮食喂养大鼠脂肪组织中的表达及其与脂肪组织炎症的关系.方法 将20只SPF级雄性Sprague-Dawley大鼠随机分为正常饮食组（SD,n=10）和高脂饮食组（HFD,n=10）喂养16w后,应用免疫组化及Western blot方法检测脂肪组织中Dll4及炎症通路NF-κB磷酸化、IL-6的表达.结果 免疫组化结果显示,HFD组Dll4表达量显著升高（P〈0.001）;Western blot结果与免疫组化结果相一致,Dll4蛋白表达量是SD组的1.34倍（P〈0.01）;磷酸化核转录因子NF-κB表达水平升高,HFD组为SD组的2.03倍（P〈0.01）;HFD组炎症细胞因子IL-6水平明显升高,为SD组的3.02倍（P〈0.01）.结论 高脂饮食可增加脂肪组织中Dll4蛋白表达,促进了脂肪组织中炎症的发生.     

肥胖大鼠瘦素信号传导通路的变化

目的筛选与人类代谢障碍性肥胖症发病病因学相似的肥胖大鼠模型,并对肥胖个体Leptin信号传导通路的改变情况进行初步研究。方法离乳雄性Wistar大鼠以高脂饲料喂养6周后,取体重增加值大的前1/4部分作为肥胖倾向组大鼠。对肥胖倾向组大鼠,继续进行高脂饲料喂养,并观察其体重、血清Leptin的变化趋势;试验49周后,大鼠处死,对内脏脂肪含量、附睾脂肪细胞大小以及下丘脑LRb（Leptin受体b亚型）表达水平及Stat3磷酸化水平（Tyr705磷酸化）进行测定。结果正常对照组大鼠和肥胖倾向组大鼠在不同饲料喂养的第17周开始体重相对增加值出现组间显著性差异;除第16周肥胖倾向组大鼠的血清Leptin浓度高于正常对照组,但不存在显著性差异之外,其它采血时间点,肥胖倾向组的血清Leptin浓度均显著高于正常对照组;动物处死后,肥胖倾向组大鼠的内脏脂肪含量和附睾脂肪细胞大小均显著大于正常对照组;两组大鼠在下丘脑LRb表达水平和细胞浆内Stat3磷酸化水平方面不存在显著性差异。结论本研究得到了与营养性肥胖人群临床表现相似的肥胖大鼠;同时发现,肥胖大鼠在长期高浓度Leptin刺激后,可能引起了中枢性Leptin抵抗,致使Leptin对体重调节的正常生理作用受到抑制,脂代谢异常的程度进一步加深,最终表现为脂肪细胞体积增大、内脏脂肪含量升高和体重增加。     

Hypolipidemic effects of crude extract of adlay seed (Coix lachrymajobi var. mayuen) in obesity rat fed high fat diet: relations of TNF-alpha and leptin mRNA expressions and serum lipid levels

To find out whether the expressions of these adipocyte markers are influenced by oriental medicine, obesity rats induced by high fat diet (HFD) for 8 weeks were injected with 50 mg/100 g body weight adlay seed crude extract (ACE), daily for 4 weeks. The results are summarized as follows: HFD + ACE group significantly reduced food intakes and body weights. Weights of epididymal and peritoneal fat were dramatically increased in HFD groups compared with those of normal diet (ND) group but significantly decreased more in HFD + ACE group than those of HFD + saline group (sham). Those of brown adipocytes were increased in HFD + ACE group compared to ND and sham groups but there was no significant difference. The sizes in white adipose tissue (WAT) by microscope were markedly larger in HFD groups than ND group but considerably reduced in HFD + ACE group compared with sham group. The levels of triglyceride, total-cholesterol and leptin in blood serum were significantly decreased in HFD + ACE group compared to those of sham group. Leptin and TNF-alpha mRNA expressions in WAT of rats were remarkably increased more in sham group than in those of ND group. Those of HFD + ACE group were significantly decreased compared with those of sham group, especially. TNF-alpha mRNA expression in HFD + ACE group was declined more than that of ND group. In conclusion, treatments of ACE modulated expressions of leptin and TNF-alpha and reduced body weights, food intake, fat size, adipose tissue mass and serum hyperlipidemia in obesity rat fed HFD. Accordingly, the oriental medicine extract, adlay seed crude extract, can be considered for obesity therapies controlling.     

Changes of skeletal muscle adiponectin content in diet-induced insulin resistant rats

The current study examined the relationship between skeletal muscle levels of adiponectin and parameters of insulin sensitivity. A high fat/sucrose diet (HFD) for 20 weeks resulted in significant increases in body weight, serum insulin, triglycerides (TG), and free fatty acids (FFA) (all p < 0.01). Interestingly, this diet leads to a slight increase in serum adiponectin, but significant decreases in gastrocnemius muscle and white adipose adiponectin (all p < 0.05). HFD for 4 weeks also resulted in a significant decrease in muscle adiponectin, which correlated with serum insulin, TG, and FFA (all p < 0.05). Treatment of the 4-week HFD rats with a PPARgamma agonist GI262570 ameliorated the diet-induced hyperinsulinemia and dyslipidemia, and effectively restored muscle adiponectin (all p < 0.05). This study demonstrated that HFD-induced hyperinsulinemia and dyslipidemia appeared without changes in serum adiponectin, but were associated with decreased tissue adiponectin. This provides the first evidence for a connection between tissue adiponectin and diet-induced hyperinsulinemia and dyslipidemia.     

Epinephrine induces PDK4 mRNA expression in adipose tissue from obese, insulin resistant rats

Thiazolidinediones (TZDs) are a commonly prescribed class of insulin sensitizing drugs that increase fatty acid re-esterification, in part through the induction of pyruvate dehydrogenase kinase 4 (PDK4). Owing to the deleterious side effects of TZDs the identification of alternative approaches with which to increase PDK4 is essential. We recently demonstrated that epinephrine increases PDK4 expression through p38 and peroxisome proliferator-activated receptor γ (PPARγ) dependent pathways in cultured adipose tissue from lean rats. The purpose of this study was to determine whether acute epinephrine treatment, in vivo, can induce PDK4 mRNA expression in adipose tissue from obese, insulin resistant rats and if the reputed signaling pathways mediating this effect are intact. To this end we fed male Wistar rats a chow or high-fat diet (HFD, 60% kcals from fat) for 6 weeks. Rats were then injected with a weight-adjusted bolus of epinephrine and tissue harvested. Despite a blunted activation of p38 epinephrine increased PDK4 mRNA expression to a similar extent in adipose tissue from chow and HFD rats. 5'AMP-activated protein kinase (AMPK) signaling was not altered by the HFD. Similar to epinephrine, 2 h of swim exercise, an intervention that increases plasma catecholamines, also increased PDK4 mRNA levels to a similar extent in adipose tissue from both lean and HFD rats. Collectively these findings demonstrate, for the first time, that acute elevations in catecholamines induce PDK4 in adipose tissue from HFD rats, that this effect is likely independent of p38, a reputed mediator of PDK4 expression and that exercise, similar to TZDs can induce PDK4 in adipose tissue from obese, insulin resistant rats.     

Momordica charantia (Bitter Melon) Reduces Obesity-Associated Macrophage and Mast Cell Infiltration as well as Inflammatory Cytokine Expression in Adipose Tissues

Obesity is a world-wide epidemic disease that correlates closely with type 2 diabetes and cardiovascular diseases. Obesity-induced chronic adipose tissue inflammation is now considered as a critical contributor to the above complications. Momordica charantia (bitter melon, BM) is a traditional Chinese food and well known for its function of reducing body weight gain and insulin resistance. However, it is unclear whether BM could alleviate adipose tissue inflammation caused by obesity. In this study, C57BL/6 mice were fed high fat diet (HFD) with or without BM for 12 weeks. BM-contained diets ameliorated HFD-induced obesity and insulin resistance. Histological and real-time PCR analysis demonstrated BM not only reduced macrophage infiltration into epididymal adipose tissues (EAT) and brown adipose tissues (BAT). Flow cytometry show that BM could modify the M1/M2 phenotype ratio of macrophages in EAT. Further study showed that BM lowered mast cell recruitments in EAT, and depressed pro-inflammatory cytokine monocyte chemotactic protein-1 (MCP-1) expression in EAT and BAT as well as interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) expression in EAT. Finally, ELISA analysis showed BM-contained diets also normalized serum levels of the cytokines. In summary, in concert with ameliorated insulin resistance and fat deposition, BM reduced adipose tissue inflammation in diet-induced obese (DIO) mice.     

Voluntary exercise improves insulin sensitivity and adipose tissue inflammation in diet-induced obese mice

Exercise promotes weight loss and improves insulin sensitivity. However, the molecular mechanisms mediating its beneficial effects are not fully understood. Obesity correlates with increased production of inflammatory cytokines, which in turn, contributes to systemic insulin resistance. To test the hypothesis that exercise mitigates this inflammatory response, thereby improving insulin sensitivity, we developed a model of voluntary exercise in mice made obese by feeding of a high fat/high sucrose diet (HFD). Over four wk, mice fed chow gained 2.3 +/- 0.3 g, while HFD mice gained 6.8 +/- 0.5 g. After 4 wk, mice were subdivided into four groups: chow-no exercise, chow-exercise, HFD-no exercise, HFD-exercise and monitored for an additional 6 wk. Chow-no exercise and HFD-no exercise mice gained an additional 1.2 +/- 0.3 g and 3.3 +/- 0.5 g respectively. Exercising mice had higher food consumption, but did not gain additional weight. As expected, GTT and ITT showed impaired glucose tolerance and insulin resistance in HFD-no exercise mice. However, glucose tolerance improved significantly and insulin sensitivity was completely normalized in HFD-exercise animals. Furthermore, expression of TNF-alpha, MCP-1, PAI-1 and IKKbeta was increased in adipose tissue from HFD mice compared with chow mice, whereas exercise reversed the increased expression of these inflammatory cytokines. In contrast, expression of these cytokines in liver was unchanged among the four groups. These results suggest that exercise partially reduces adiposity, reverses insulin resistance and decreases adipose tissue inflammation in diet-induced obese mice, despite continued consumption of HFD.     

Sex hormone-binding globulin overexpression protects against high-fat diet-induced obesity in transgenic male mice

Obese subjects of all ages and sex have reduced plasma SHBG levels. Whether these low plasma SHBG levels play a role in obesity development is unknown. In the present work we wanted to explore if SHBG overexpression could prevent obesity development induced by high fat diet (HFD). To do so, we fed humanized SHBG transgenic male mice and their wild-type littermates with control diet (CD) or HFD over the course of 8 weeks. The results showed that SHBG overexpression protected against body weight gain and fat accumulation induced by HFD. In addition, SHBG overexpression also abrogated the increase in insulin, leptin and resistin levels, as well as the reduction in adiponectin, induced by HFD. Mechanistically, the SHBG protection against HFD-induced obesity was achieved by stimulating lipolysis in white adipose tissue. Furthermore, we have demonstrated the SHBG cell-autonomous effect using human primary visceral adipocytes. Taking together, our results demonstrate that SHBG overexpression protects against diet-induced obesity and improves the metabolic profile of male mice fed a HFD diet.