高脂饮食诱导的内脏肥胖小鼠模型存在性别差异

目的:比较不同性别BALB/c小鼠采用高脂饮食建立肥胖模型的差异。方法:32只4周龄无特定病原体级BALB/c小鼠（雌雄各半）随机分为雌性对照组、雌性高脂组、雄性对照组和雄性高脂组,每组8只。雌性对照组和雄性对照组采用普通饮食,雌性高脂组和雄性高脂组采用高脂饲料喂养,喂养12周后测量小鼠体重、内脏脂肪比、空腹血糖、葡萄糖耐量、血脂、代谢相关激素水平,并采用16S rRNA测序检测小鼠粪便菌群构成。结果:高脂饮食干预导致雄性小鼠体重和内脏脂肪比明显增加,病理表现为单个脂肪面积明显增大,肝脏脂肪滴堆积,总胆固醇、空腹血糖、口服糖耐量试验时间-血糖曲线下面积以及血清胰岛素水平明显上升（均P<0.05）,并出现明显胰岛素抵抗（P<0.01）。而雌性高脂组体重、内脏脂肪比、血清胰岛素和瘦素水平与雌性对照组差异均无统计学意义（均P>0.05）。高脂干预后小鼠肥胖相关肠道菌群相对丰度显著变化并存在性别差异,其中雄性高脂组肥胖相关菌属（如布劳特菌）相对丰度明显增加,菌群结构变化更明显。结论:高脂饮食喂养12周4周龄BALB/c雄性小鼠可稳定建立以内脏脂肪堆积、代谢功能紊乱和肠道菌群变...     

Dietary obesity in exercising or cold-exposed Syrian hamsters

High-fat diet-feeding increases body weight and adiposity in Syrian hamsters (Mesocricetus auratus), effects due in part to decreased energy expenditure. The effects of voluntary exercise- or cold exposure-induced increases in energy expenditure were examined in fat- or chow-fed, female Syrian hamsters. In Experiment 1, voluntary exercise (10 weeks) caused a moderate hyperphagia and actually increased body weight in both diet groups through increases in lean body mass. Carcass lipid was not affected by by exercise in chow-fed hamsters and only slightly reduced in fat-fed animals. In Experiment 2, chronic (8 weeks) cold exposure (5 degrees C) increased energy intake to the same extent in both dietary groups relative to the warm-exposed (23 degrees C) controls. High-fat diet-induced obesity was largely prevented by cold exposure. Cold exposure reduced lean body mass in chow-fed hamsters, but this carcass component was spared by fat-feeding. These results indicate that the increased metabolic demands of cold exposure were more effective in preventing this form of diet-induced obesity than those of voluntary exercise (80% and 17% reductions in carcass lipid, respectively). These results are discussed in terms of possible beneficial effects of eating a lipid-rich diet prior to winter.     

Resistance to diet-induced obesity is associated with increased proopiomelanocortin mRNA and decreased neuropeptide Y mRNA in the hypothalamus

Mechanisms mediating genetic susceptibility to diet-induced obesity have not been completely elucidated. Elevated hypothalamic neuropeptide Y (NPY) and decreased hypothalamic proopiomelanocortin (POMC) are thought to promote the development and maintenance of obesity. To assess the potential role of hypothalamic neuropeptide gene expression in diet-induced obesity, the present study examined effects of a high-fat diet on hypothalamic NPY and POMC mRNA in three strains of mice that differ in susceptibility to develop diet-induced obesity. C57BL/6J, CBA, and A/J mice were fed either normal rodent chow or a high-fat diet for 14 weeks after which hypothalamic gene expression was measured. On the high-fat diet, C57BL/6J mice gained the most weight, whereas A/J mice gained the least weight. On the high-fat diet, NPY mRNA significantly decreased as body weight increased in CBA and A/J mice, but not in C57BL/6J mice. In addition, POMC mRNA significantly increased as body weight increased in A/J mice, but not in CBA and C57BL/6J mice. Since decreased NPY mRNA and increased POMC mRNA would presumably attenuate weight gain, these results suggest that a high-fat diet produces compensatory changes in hypothalamic gene expression in mice resistant to diet-induced obesity but not in mice susceptible to diet-induced obesity.     

Weight cycling did not increase tumor incidence in high fat–fed rats treated with a low-dose 7,12-dimethylbenzyl(1)anthracene

The present study tested the hypothesis that weight cycling (WC, repeated weight gain and loss) increases the tumorigenesis in rats exposed to carcinogen. Female Wistar rats consumed a high-fat diet (35% weight per weight) and were divided: (1) ad lib–fed rats that were treated with 7,12-dimethylbenzyl(1)anthracene (DMBA, 2 mg) at 55 days of age (AL-DMBA); (2) WC rats that were treated with DMBA (WC-DMBA); and (3) vehicle-treated WC rats (WC-VEH). In this study, WC did not alter blood parameter concentrations and did not influence insulin sensitivity. Mammary tissue F₂-isoprostane concentrations were lowest in WC-VEH and highest in AL-DMBA groups. Tumor incidence and burden were similar among all groups. The data obtained from this study do not support our hypothesis. This may be due to low dose of DMBA used, strain and age of the rats, number of WC cycles, and the amount of trans–fatty acids in the diets.     

Correlation analysis of intestinal flora and pathological process of type 2 diabetes mellitusOA

Objective: To observe the relationship between the different stages of type 2 diabetes mellitus(T2DM)and the intestinal flora and verify its underlying mechanism.Methods: T2DM rats were generated by high-fat diet(HFD) combined with intraperitoneal streptozotocin(STZ) injection. The rats were divided into four groups: the control group(fed with normal feed for1 month), the HFD group(fed with HFD for 1 month), the T2DM group(HFD combined with STZ and blood glucose ≥11.1 m M), and the unformed T2DM...     

不同高脂饲料对小鼠肥胖和胰岛素抵抗模型制备情况的效果比较

目的:探讨两种不同的高脂饲料在C57/BL6J小鼠肥胖和胰岛素抵抗(IR)模型制备过程中的效果差别,以期为更好的制备C57/BL6J小鼠肥胖和IR模型提供理论指导.方法:以雄性C57/BL6小鼠为实验材料,随机分为三组,分别为基础组,喂食国内A公司啮齿动物基础饲料;模型1组,喂食国内A公司生产的啮齿动物高脂饲料(HFD...     

硫酸锌对高脂喂养载脂蛋白E基因敲除小鼠主动脉基质金属蛋白酶-9和CD40表达的影响

目的探讨硫酸锌对高脂喂养载脂蛋白E（ApoE）基因敲除小鼠血脂和氧化低密度脂蛋白（oxLDL）水平,及主动脉中基质金属蛋白酶9（MMP-9）和细胞分化抗原40（CD40）mRNA表达的影响。方法 AopE基因敲除小鼠连续14周喂饲高脂饲料,同时分别给予小鼠浓度为2.5、25 mmol/L硫酸锌水溶液作为低剂量组和高剂量组。测定小鼠血脂和oxLDL水平,并测定主动脉中MMP-9和CD40 mRNA表达水平。结果低剂量组和高剂量组小鼠血清中甘油三酯和oxLDL水平明显低于动脉粥样硬化（AS）模型组（P〈0.01）。低剂量组和高剂量组小鼠主动脉MMP-9 mRNA和CD40 mRNA水平与AS模型组没有差异。结论补充硫酸锌降低了AS模型动物的甘油三酯和oxLDL水平,具有潜在的抗AS作用,但对主动脉MMP-9和CD40 mRNA表达无影响。     

高脂或高糖饮食诱导胰岛素抵抗大鼠的附睾脂肪组织视黄醇结合蛋白4表达

目的观察不同膳食结构,即高脂或高糖饮食对大鼠附睾脂肪组织视黄醇结合蛋白4(RBP4)表达的影响。方法雄性SD大鼠随机分为3组,普通饮食组予普通饲料,高脂饮食组予高脂饲料,高糖饮食组予高糖饲料。喂养8周后,行口服糖耐量试验检测胰岛功能,取空腹血清测血糖、血脂和胰岛素水平等,并取附睾和肾周脂肪组织,称重,计算脂体比,免疫组织化学定量检测附睾脂肪组织RBP4表达水平,反转录-聚合酶链反应检测附睾脂肪组织RBP4和葡萄糖转运子4(GluT4)mRNA表达水平。结果8周后,高脂和高糖饮食组大鼠空腹胰岛素水平和胰岛素抵抗均显著高于普通饮食组(P值均＜0．01)。高脂和高糖饮食组大鼠0、30、60及120min血糖、胰岛素水平均显著高于普通饮食组(P值分别＜0．05、0．01),胰岛素曲线下面积(AUC_(INS))均显著高于普通饮食组(P值均＜0．01)。与普通饮食组相比,高脂和高糖饮食组大鼠糖耐量减退、空腹血糖和胰岛素升高、脂体比增加(P值分别＜0．05、0．01)。高脂和高糖饮食组大鼠三酰甘油水平显著高于普通饮食组(P值均＜0．01),两组附睾脂肪组织RBP4 mRNA水平分别是普通饮食组的2．35倍和2．47倍(P值均＜0．05),而GluT4则为普通饮食组的73．1%和66．7%(P值均＜0．05)。结论高脂和高糖饮食均能引起内脏脂肪组织RBP4表达增加, RBP4可能与腹内型肥胖相关。     

儿茶素对营养性肥胖大鼠代谢综合征的防治作用

目的探讨儿茶素对高脂饮食诱发的营养性肥胖大鼠代谢综合征的防治作用。方法高脂饮食建立营养性肥胖大鼠模型,应用儿茶素作为干预性药物,检测大鼠体重及血清甘油三酯(TG)、总胆固醇(TC)、游离脂肪酸(FFA)、低密度脂蛋白-C(LDL-C)、高密度脂蛋白-C(HDL-C)、空腹血糖(FBG)、空腹胰岛素(FINS)水平的变化,探讨儿茶素对营养性肥胖和代谢综合征的干预作用。结果高脂饮食组大鼠体重增加并显著高于普通饮食组(P<0.01),经过儿茶素处理后体重略有下降,但未见明显统计学差异(P>0.05)。高脂饮食组大鼠血清TG、TC、FFA、LDL-C、FBG、FINS均高于普通饮食组,而HDL-C则低于普通饮食组(P<0.01)。儿茶素处理后高脂饮食组大鼠血清TG、TC、FFA、LDL-C、FBG、FINS均有所下降(P<0.05)。而儿茶素对于正常饮食大鼠血清各生化指标没有明显影响。结论儿茶素可有效防治高脂饮食引起的大鼠营养性肥胖及代谢综合征。     

鸡骨草醇提物对大鼠非酒精性脂肪肝的保护作用研究

目的:研究鸡骨草醇提物对高脂饲料加四氯化碳(CCl4)所致大鼠脂肪肝的保护作用。方法:采用高脂饲料加四氯化碳(CCl4)复合诱导大鼠脂肪肝模型.实验分为5组,即正常对照(生理盐水2mL.kg-1)、模型(生理盐水2mL.kg-1)与鸡骨草醇提物高、中、低剂量(40、30、20g.kg-1)组,ig给药,每天1次,连续2周。检测大鼠血清中天冬氨酸氨基转移酶(AST)、丙氨酸氨基转移酶(ALT)含量及体重、肝重,计算肝脏系数,并观察各组大鼠肝组织病理学变化。结果:与模型组比较,鸡骨草醇提物高、中、低剂量组大鼠血清中AST、ALT含量及肝脏系数显著降低,AST/ALT值升高(P<0.01);大鼠肝脏系数显著降低(P<0.05);肝组织病理学明显改善。结论:鸡骨草醇提物可降低病鼠肝脏系数和血清中ALT、AST含量,减轻肝细胞脂肪变性及病理损伤,对高脂饲料配合CCl4所致大鼠脂肪肝有改善作用。