肉碱对不全饥饿大鼠脂肪利用的影响

目的　探讨肉碱对不全饥饿大鼠脂肪利用的影响。方法　用限食的方法造成不全饥饿大鼠模型 ,在给予高脂饲料基础上观察对照组与给予肉碱的实验组血浆肉碱浓度、附睾脂肪垫重量、粪便中脂肪含量、尿酮体、糖原等指标的变化。结果　补充肉碱后 ,实验组动物血浆总肉碱浓度显著高于对照组 ( P<0 .0 0 1 ) ;附睾脂肪组织重量及粪便中脂肪含量均显著低于对照组 ( P<0 .0 5) ,而肝糖原和肌糖原含量显著高于对照组 ( P<0 .0 5) ;实验前期和中期实验组尿酮体排出减少 ,与对照组相比 P<0 .0 5。结论　补充肉碱对不全饥饿大鼠脂肪利用有一定的促进作用     

高脂和限食对不同肥胖易感性大鼠能量代谢的影响

目的探讨不同肥胖易感性大鼠在高脂饲料及半量限食状态下能量代谢的差异。方法健康雄性SD大鼠60只,高脂饲料喂养3周,按体重增加量排序筛选出肥胖易感(obesity-prone,OP)、肥胖抵抗(obesity-resistant,OR)和对照组,继续喂养12周;由各组随机挑选一半动物进行半量限食饲喂,另一半继续自由采食,持续2周。间接测热法测量大鼠基础代谢率(BMR)、静息代谢率(RMR)等代谢指标;处死动物,分离肾周、睾周和大网膜脂肪,计算体脂百分比。结果在高脂饲料状态下,OR大鼠BMR、RMR显著高于OP组和对照组;在半量限食状态下,OR大鼠BMR、RMR显著低于OP组和对照组。在限食状态下OP、OR及对照组大鼠BMR、RMR较自由采食状态均有所降低,OR组降幅最大;经过2周限食后,OP组体脂百分比下降显著,而OR组基本无变化。结论 OP、OR大鼠在高脂饲料或半量限食状态下代谢水平均存在显著差异,OR较OP对能量摄入水平的变化反应更为灵敏。     

高糖高脂饲料对Wistar大鼠生长和糖脂代谢的影响

目的观察高糖高脂饲料对Wistar大鼠生长及糖脂代谢的影响。方法雄性Wistar大鼠20只,按体重和空腹血糖随机分为2组(n=10):对照组和实验组,分别以普通饲料和高糖高脂饲料喂养6周,观察大鼠的生长曲线、食物利用率,测定大鼠的糖脂代谢指标。结果喂养6周后,实验组大鼠的体重、食物利用率、内脏脂肪占体重百分比、血清总胆固醇和低密度脂蛋白胆固醇均显著高于对照组(P<0.05),血清高密度脂蛋白胆固醇显著低于对照组(P<0.01)。两组的空腹血糖(FPG)无显著差异。实验组大鼠的糖耐量降低,葡萄糖曲线下面积显著高于对照组。结论正常血糖状态下,高糖高脂饲料可引起Wistar大鼠中心型积聚的体脂增加,血清总胆固醇增加,导致葡萄糖耐量能力减退,为2型糖尿病进程中的重要危险因素。     

L-肉碱对高脂膳食诱导肥胖大鼠体脂含量及血脂水平的影响

[目的]探讨L-肉碱对肥胖大鼠体重、体脂含量及血脂水平的影响。[方法]以高脂饲料诱导大鼠肥胖模型，然后将肥胖大鼠随机分为对照组与125、250、500mg／kg体重3个L-肉碱组，每天1次经口给予，共6周。观察大鼠体重、睾丸 肾脂肪垫合计重量，TC、TG和HDL-C水平的变化。[结果]125、250、500mg／kg剂量组动物的体重与甘油三酯(TG)低于对照组；250、500mg／kg剂量组的睾丸 肾脂肪垫重量低于对照组；500mg／kg剂量组的胆固醇(TC)、高密度脂蛋白胆固醇(HDL-C)和体脂比低于对照组。[结论]L-肉碱具有改善大鼠肥胖与降低高血脂水平的作用。     

大豆蛋白对高血胆固醇模型大鼠胆固醇代谢的影响

目的:探讨膳食大豆蛋白对高胆固醇模型大鼠血浆胆固醇及其有关血脂指标的影响,并对其可能的作用机理加以研究。方法: 4周龄断乳雄性Wistar大鼠,经28d诱发高血胆固醇以后,按体重和血浆总胆固醇浓度将动物均衡分为两组,分别喂饲含酪蛋白和大豆蛋白的纯合成高脂饲料56d。结果:经28d诱导高脂模型后,高血胆固醇模型大鼠的TC浓度是阴性对照组的1 51倍。又经56d喂饲含有处理因素的饲料后,同酪蛋白组相比,大豆蛋白组动物TC,TG,apoB含量显著降低,而FT4水平显著高于酪蛋白组(P<0. 05)。膳食大豆蛋白摄入可降低高血胆固醇模型大鼠TC、TG、apoB浓度、使血浆FT4含量增高,但对HDL-C,apoA,FT3,TSH和胰岛素(INS)水平无影响。结论:大豆蛋白可影响血浆胆固醇水平,但其相应的作用机理还需进一步探讨。     

半饥饿状态下血浆、肝脏游离氨基酸浓度变化的比较

目的　观察比较半饥饿状态下血浆、肝脏游离氨基酸浓度的变化及其意义。方法雄性 Wistar大鼠 ,半量限食造成半饥饿模型 ,实验 4w后采空腹血和肝脏测定游离氨基酸浓度。结果　动物半饥饿后 ,血浆游离非必需氨基酸浓度下降幅度大于必需氨基酸浓度的下降幅度 ,芳香族氨基酸、支链氨基酸、精氨酸、蛋氨酸下降幅度大于 40 % ;肝脏游离氨基酸中丝氨酸、谷氨酸的浓度下降幅度大于 80 % ,亮氨酸、异亮氨酸、赖氨酸的浓度下降幅度大于 40 %。结论　半饥饿后 ,血浆、肝脏大多数游离氨基酸浓度显著下降 ,但是 ,两者的变化不尽一致     

饮食对下丘脑神经肽Y基因表达及肥胖影响

目的探讨高脂饮食对大鼠神经肽Y(NPY)基因表达及分泌的影响及大鼠肥胖易感性差异的机制.方法36只雌性SD大鼠按体重随机分为高脂实验组和基础对照组,分别给予高脂饲料和基础饲料喂养13周.据13周末体重从高脂饲料组选出体重最重和体重最轻者各9只为饮食诱导肥胖(DIO)和饮食诱导肥胖抵抗(DIR)组,比较各组大鼠能量摄入水平、血浆和下丘脑匀浆NPY及下丘脑NPY mRNA表达的差异.结果DIO组大鼠能量摄入量、下丘脑和血浆NPY水平之比显著高于DIR组和对照组(P＜0.01),DIO组大鼠下丘脑NPYmRNA表达显著高于DIR及对照组,而上述各指标DIR与对照组问差异均无统计学意义(P＞0.05).结论高脂饮食喂养条件下,SD大鼠表现为明显的肥胖易感性差异,这种差异与大鼠的能量摄入水平有关,下丘脑NPY高水平表达和分泌可能是导致肥胖易感大鼠多食和热能摄入过多的内在机制之一.     

高脂饲料与脂肪乳致大鼠肝脏脂肪变性及肝功能损伤的比较研究

目的比较由2种高脂膳食（高脂饲料和脂肪乳液）引起的大鼠肝脏脂肪变性和肝损伤程度。方法 SPF级SD种雄性大鼠36只,以血清总胆固醇水平分组,每组12只。实验设基础饲料组、高脂饲料组、脂肪乳液组3组,基础饲料组摄食基础饲料,高脂饲料组摄食高脂饲料,脂肪乳液组以1mL/kg.BW灌胃给予脂肪乳液并摄食基础饲料,试验进行30 d。终期检测血清生化指标：谷丙转氨酶（ALT）、谷草转氨酶（AST）、总蛋白（TP）、白蛋白（ALB）、碱性磷酸酶（ALP）、甘油三酯（TG）、总胆固醇（TC）;取肝脏1叶制成匀浆检测丙二醛（MDA）、超氧化物歧化酶（SOD）、还原性谷胱甘肽过氧化物酶（GSH-PX）、TP、TC、TG水平,另取肝脏1叶进行肝脏组织病理学检查。结果与基础饲料组比较,高脂饲料组形成高胆固醇血症,血清ALT、AST、ALP、TC水平均升高,血清TP、ALB水平显著下降,肝组织MDA含量显著升高,肝脏TC水平显著上升,肝脏TP、TG水平显著下降,差异均有统计学意义（P〈0.05或P〈0.01）;病理组织学检查见严重脂肪变性。与基础饲料组比较,脂肪乳液组形成混合型高脂血症,血清ALP、TC、TG水平显著升高,肝脏TC水平显著上升,肝组织SOD含量降低,差异均有统计学意义（P〈0.05或P〈0.01）;病理组织学检查见轻微脂肪变性。2种高脂膳食引发肝脏脂肪变性与肝损伤程度有所不同,与高脂饲料组比较,脂肪乳组的血清TP、ALB、TG水平显著升高,ALT、ALP、TC水平显著降低,肝脏TP、TG水平显著升高,肝组织SOD、MDA含量显著降低,差异均有统计学意义（均P〈0.01）。结论高脂饲料较脂肪乳液更能引发大鼠严重肝脂肪变性及肝功能损伤。     

高脂饲料诱导的非酒精性脂肪肝大鼠模型建立及其血浆nesfatin-1的变化

目的建立高脂饲料诱导的非酒精性脂肪肝(nonalcoholic fatty liver disease,NAFLD)大鼠模型,并观察其血浆摄食抑制因子nesfatin-1变化。方法雄性SPF级SD大鼠,随机分为对照组(n=6)和模型组(n=10)。对照组大鼠给予标准对照饲料,模型组则采用高脂饲料诱导NAFLD模型。葡萄糖耐量实验方法观察糖代谢变化,化学发光法检测血清丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)、总胆红素(TBIL)、直接胆红素(DBIL)、间接胆红素(IBIL)、总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)水平,ELISA方法检测血浆nesfatin-1、胰岛素及瘦素浓度。肝脏湿重、肝指数及肝脏形态学观察,Western blot方法观察β-catenin、磷酸化β-catenin(p-β-catenin)及cyclin D1蛋白在肝脏的表达。结果与对照组比较,高脂饲料组大鼠体重、肝脏湿重和肝指数显著增加,血清ALT、TBIL、IBIL、TC、LDL-C及血浆nesfatin-1浓度显著上升,腹腔注射葡萄糖耐量实验的曲线下面积显著升高,而胰岛素及瘦素浓度则明显下降。相关性分析结果表明,血浆nesfatin-1浓度与瘦素浓度呈负相关(r=-0.571,P=0.021)。HE染色结果显示高脂饲料组大鼠肝脏呈现轻度炎症反应及程度不等的脂肪变性。Western blot结果表明高脂饲料组大鼠肝脏cyclin D1蛋白表达上调,而p-β-catenin表达则显著减少。结论高脂饲料连续喂养4周可诱导大鼠NAFLD样代谢紊乱的表现,并且nesfatin-1可能参与这一过程。     

染料木黄酮对高脂饮食喂养大鼠肝脏脂质代谢和AMPK磷酸化的影响

目的探讨染料木黄酮（Gen）对高脂饮食喂养大鼠肝脂质代谢和肝脏腺苷酸环化酶蛋白激酶（AMPK）磷酸化的影响。方法36只大鼠适应性喂养1周后随机分为4组：正常对照组（正常组）、模型对照组（模型组）、Gen高剂量干预组（Gen高组）和Gen低剂量干预组（Gen低组）。正常组大鼠给予基础饲料D12450B（脂肪供能占10％）喂养,模型组给予D12492高脂饲料（脂肪供能占60％）喂养,Gen高组给予D12492高脂饲料喂养和8mg／kgGen灌胃干预,Gen低组给予D12492高脂饲料喂养和4mg／kgGen灌胃干预。持续喂养12周后,处死所有大鼠。取血和肝组织进行相关指标的检测。全自动生化检测仪检测血清和肝组织匀浆甘油三酯（TG）、总胆固醇（TC）、高密度脂蛋白胆固醇（HDL—C）和低密度脂蛋白胆固醇（LDL—C）水平,游离脂肪酸（FFA）试剂盒检测血清和肝组织匀浆FFA水平,Westernblot法检测肝组织总AMPK和磷酸化腺苷酸环化酶蛋白激酶（pAMPK）的表达。结果与正常组比,模型组大鼠肝脏血清和肝组织TG、TC、FFA及血清LDL—C明显升高（P〈0．05或P〈0．01）,肝组织pAMPK水平显著降低（P〈0．01）。与模型组相比,Gen低组大鼠血FFA、肝FFA和TG含量明显降低（P〈0．05或P〈0．01）;Gen高组大鼠血TC、TG、LDL—C、FFA和肝TG、FFA含量明显低于模型组大鼠（P〈0．05或P〈0．01）。与模型对照组相比,低、高剂量Gen干预均能显著上调pAMPK水平（P〈0．01和P〈0．05）;但各组大鼠肝组织总AMPK水平差异无统计学意义（P〉0．05）。结论染料木黄酮能够改善12周高脂饮食诱导的大鼠肝脂肪代谢紊乱,减轻肝脏脂质沉积,其作用机制可能与其增加pAMPK水平有关。     

膳食钙对高脂膳食大鼠血糖、血脂及激素的影响

目的　探讨不同剂量膳食钙对高脂膳食大鼠血糖、血脂及激素水平的影响。方法　将雄性Wistar大鼠随机分成 6组 ,每组 9只 ,分别喂以基础饲料A组 (5 %脂肪 ,0 5 %钙 )、高脂低钙饲料B组 (15 %脂肪 ,0 0 8%钙 )、高脂正常钙饲料C组 (15 %脂肪 0 5 %钙 )、高脂高钙饲料D和E组(15 %脂肪 ,1%和 1 5 %钙 )和高脂高钙 (15 %脂肪 ,1 5 %钙 ) +维生素D(6 0 0IU % )饲料F组。 9周后断头取血测血糖、血脂和血清胰岛素、甲状腺激素、生长激素和血浆神经肽Y。结果　与C组相比 ,其它各组大鼠体重和体脂含量均显著降低 (P <0 0 5 ) ,胆固醇和甘油三酯各组与C组相比显著降低 (P <0 0 5 ) ,高密度脂蛋白各组均无显著性差异 (P >0 0 5 ) ;C组血糖和胰岛素均增高 ,与C组相比 ,E组胰岛素显著降低 (P <0 0 5 ) ,D、E、F组FT3显著增加 (P <0 0 5 ) ,E、F组神经肽Y(NPY)显著降低 ,其余各组无显著性差异 (P >0 0 5 ) ,生长激素各组间无显著性差异 (P >0 0 5 )。结论　高钙膳食可能通过降低血清胆固醇和甘油三酯 ,改善高胰岛素血症 ,降低血浆NPY ,提高血清FT3的水平 ,从而抑制了高脂膳食诱导的肥胖。     

Effect of corn gluten and its hydrolysate consumptions on weight reduction in rats fed a high-fat diet

This study examined the effects of corn gluten (CG) and its hydrolysate consumptions on weight reduction in rats fed a high-fat diet. Eight-month-old male Sprague-Dawley rats (n=40) were fed a high-fat diet (40% calorie as fat) for 4 weeks. They were then randomly divided into four groups and fed the isocaloric diets with different protein sources for 8 weeks. The protein sources were casein (control group), intact CG (CG group), CG hydrolysate A (CGHA group, 30% of protein as peptides and 70% as free amino acids) and CG hydrolysate P (CGHP group, 93% of protein as peptides and 7% as free amino acids). Body weight gain, adipose tissue weights, nitrogen balance, absorptions of energy, protein and fat, lipid profiles in plasma, liver and feces and hepatic activities of carnitine palmitoyl transferase (CPT), fatty acid synthase (FAS), malic enzyme (ME) and glucose-6-phosphate dehydrogenase (G6PDH) were assessed. The CGHA diet had the highest amount of BCAAs, especially leucine, and most of them existed as free amino acid forms. The CGHA group showed significant weight reduction and negative nitrogen balance. Protein absorption and apparent protein digestibility in the CGHA group were significantly lower than those in other groups. Adipose tissue weights were the lowest in the CGHA group. Activity of CPT tended to be higher in the CGHA group than in other groups and those of FAS, ME and G6PDH were significantly lower in the CGHA group than in other groups. In conclusion, the CGHA diet which had relatively high amounts of free amino acids and BCAAs, especially leucine, had a weight reduction effect by lowering adipose tissue weight and the activities of FAS, ME and G6PDH in experimental animals, but it seemed to be a negative result induced by lowering protein absorption, increasing urinary nitrogen excretion and protein catabolism.     

Effect of Chlorella vulgaris on lipid metabolism in Wistar rats fed high fat diet

This study was performed to investigate effects of Chlorella vulgaris on lipid metabolism in rats fed high fat diet. Sixty 6-week-old male Wistar rats were divided into two groups; normal diet group and high fat diet group, then the rats in each group were further divided into three subgroups and fed 0%, 5% and 10% (w/w) chlorella-containing diets, respectively, and raised for 9 weeks. Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activity and total protein and albumin concentration were not different among groups. Serum total lipids and liver TG concentration were significantly lower in 5% and 10% chlorella groups than 0% chlorella group in high fat diet groups (p<0.05). Serum TG, serum total cholesterol, liver total lipid and liver total cholesterol concentrations were significantly lower in 10% chlorella groups than 0% chlorella group in high fat diet groups (p<0.05). Fecal total lipid, TG and total cholesterol excretions were significantly higher in 5% and 10% chlorella groups than 0% chlorella groups in normal diet and high fat diet groups, respectively (p<0.05). These results suggest that Chlorella vulgaris is effective for prevention of dyslipidemia which may be due to the modulation of lipid metabolism and increased fecal excretion of lipid.     

The effect of a high fat diet on the carnitine content of skeletal and cardiac muscle from streptozotocin-diabetic and control rats

Streptozotocin-diabetic (SZ) and control rats were maintained on high fat (HF) or on low fat (LF) diets for a period of two weeks. Skeletal and cardiac muscle were assayed for free fatty acids and for free, short-chain, and long-chain carnitine. The free fatty acid content of both skeletal and cardiac muscle was increased in SZ rats fed the LF diet and was not augmented appreciably by HF feeding. The level of free carnitine was decreased in muscles from diabetic animals maintained on the LF regimen and was unaffected by the HF diet. The amount of long-chain carnitine esters was increased in both skeletal and cardiac muscle from LF-fed SZ rats and decreased in heart from HF-fed diabetic animals. The absolute amounts of free and long-chain carnitine measured in tissue from the LF fed control rats did not differ consistently from those in muscles from HF-fed control rats. However, the long-chain carnitine/free carnitine ratio was elevated significantly in both skeletal and cardiac muscle from the HF-fed control animals, but was not increased in SZ rats maintained on the HF regimen. Together, these data suggest that high fat feeding results in increased lipid utilization in control but not in diabetic rats.     

Necessity of carnitine supplementation in semistarved rats fed a high-fat diet.

We investigated the effects of carnitine supplementation on lipid metabolism in semistarved rats. The semistarved rats were fed a high-fat diet and half the normal energy intake for 2 wk. Carnitine was supplied daily at a dose of 250 mg/kg of body weight. The results showed that the concentration of plasma free carnitine increased significantly in semistarved and carnitine-supplemented rats compared with normal and semistarved rats. The activities of muscle carnitine palmitoyltransferase I and preheparin plasma lipoprotein lipase also were significantly increased in semistarved and carnitine-supplemented rats. The plasma triacylglycerol secretion rate was restored to normal by carnitine supplementation in semistarved rats. Urinary excretion of ketone bodies was reduced significantly after carnitine supplementation. We concluded that supplementation of carnitine can significantly increase the concentration of plasma free carnitine and improve lipid metabolism in semistarved rats fed a high-fat diet.     

Metabolism of cholesterol is altered in the liver of C3H mice fed fats enriched with different C-18 fatty acids.

We examined whether the degree of saturation of C-18 fatty acids influenced hepatic cholesterol metabolism in C3H mice. The mice were fed diets containing 20 g/100 g fat, enriched in stearic (18:0), oleic (18:1) or linoleic acid (18:2) with or without 1 g/100 g cholesterol. Plasma total cholesterol concentration was lower in mice fed the 18:0 diet relative to those fed the 18:1- or 18:2-enriched diets (P < 0.05) regardless of dietary cholesterol supplementation. Dietary cholesterol significantly raised hepatic total cholesterol concentration (P < 0.05) in those fed the 18:1- and 18:2-enriched diets, but not in mice fed the 18:0-enriched diet. Dietary cholesterol raised biliary cholesterol concentration (P < 0. 05) in mice fed the 18:1- and 18:2-enriched diets, but not in mice fed the 18:0-enriched diet. The cholesterol saturation index was variably affected by the fat diets. Feeding diets containing cholesterol suppressed the hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) activity and induced acyl coenzyme A:cholesterol acyl transferase (ACAT) activity compared with feeding diets without cholesterol (P < 0.05), indicating that the liver was exposed to dietary cholesterol. Hepatic ACAT activity was lower in mice fed the 18:0-enriched diet compared with those fed the 18:1- or 18:2-enriched diets (P < 0.05). Addition of cholesterol to the 18:1 diet induced the largest increase of hepatic ACAT activity, and this was associated with the enrichment of VLDL with cholesterol. Varying the degree of saturation of C-18 fatty acids influences the metabolism and disposition of hepatic cholesterol.     

粗杂粮对大鼠脂代谢紊乱干预作用的机制探讨

目的观察粗杂粮对大鼠脂代谢紊乱及其脂肪组织过氧化物酶体增殖物激活受体γ (PPARγ) mRNA表达水平的影响,探讨粗杂粮改善脂代谢紊乱的作用机制。方法44只SPF级大鼠随机分为阴性对照组(饲常规饲料)和3个实验组(饲高脂饲料6周),造模成功后分别给予高脂粗杂粮、高脂米面和高脂模型饲料共15周。结果粗杂粮高脂组的血清总胆固醇(TC)、总甘油三酯(TG)、白细胞介素-6(IL-6)和C反应蛋白(CRP)显著低于高脂模型组(P<0.05),血清高密度脂蛋白胆固醇(HDL-C)水平显著高于高脂模型和米面高脂组(P<0.05),脂蛋白酯酶(LPL)和肝酯酶(HL)活性及肿瘤坏死因子-α(TNF-α)最接近阴性对照组水平;粗杂粮高脂组白色脂肪组织PPARγ mRNA的表达水平明显高于高脂模型组和米面高脂组(P<0.05)。结论复配式粗杂粮可以激活PPARγ,促进脂肪细胞LPL和HL活性逐步恢复,使血脂水平下降;同时抑制和减少IL-6、TNF-α及CRP的产生,炎症反应减轻,脂代谢紊乱得到改善。     

牛磺酸和鸡冠花提取物对大鼠血清锌、铜、钙的影响

ＳＤ大鼠４０只，喂基础饲料预试验观察１周后，随机分为阴性对照组（ＮＧ）、高脂对照组（ＨＦ）、牛磺酸（ＴＡ）组、鸡冠花提取物（ＥＣ）组，每组１０只。ＮＧ组喂基础饲料，其余各组均喂高脂饲料，连续８周；ＴＡ组每日灌胃ＴＡ１００ｍｇ／ｋｇ，ＥＣ组。每日灌胃ＥＣ１００ｍｇ／ｋｇ。结果表明，牛磺酸和鸡冠花提取物不仅能显著增加高脂大鼠红细胞ＳＯＤ水平，降低动脉壁ＴＣ、ＭＤＥ及血清ＬＤＨ含量（Ｐ＜０．０５或Ｐ＜０．０１），而且可显著提高血清锌含量（Ｐ＜０．０５），同时鸡冠花可提高高脂大鼠血清铜含量（Ｐ＜０．０１）。牛磺酸和鸡冠花显著地降低了高脂大鼠的血清铜／锌比值（Ｐ＜０．０１），并有降低血清钙的作用。提示牛磺酸和鸡冠花可能通过调节体内的锌、铜、钙水平，进而影响脂质代谢及动脉粥样硬化形成