钙对高脂膳食大鼠体重水平的影响

目的研究高钙膳食和维生素D(VD)对高脂致肥大鼠体重水平的影响.方法将30只Wistar雄性大鼠随机分为3组A组饲以高脂饲料,B组和C组饲以高脂强化钙饲料.饲养1周后,C组大鼠肌肉注射VD 15 μg/(kg*bw),A、B 2组大鼠同时同部位注射同剂量生理盐水,连续28 d.结果 B组和C组体重显著低于A组(P＜0.01);B组的大鼠附睾、肾周脂肪重量显著低于A组(P＜0.05);B组的胆固醇水平显著低于A组(P＜0.05).结论提示高钙膳食可能影响大鼠血脂水平,减少脂肪在腹部的沉积,从而起到减轻大鼠体重的作用.未观察到维生素D促进钙的吸收,进而影响脂质的吸收和血脂水平的作用.     

Lipid profile and insulin sensitivity in rats fed with high-fat or high-fructose diets

The occurrence and severity of obesity- and insulin resistance-related disorders vary according to the diet. The aim of the present longitudinal study was to examine the effects of a high-fat or a high-fructose diet on body weight (BW), body fat mass, insulin sensitivity (IS) and lipid profiles in a rat model of dietary-induced obesity and low IS. A total of eighteen, 12-week-old male Wistar rats were divided into three groups, and were fed with a control, a high-fat (65 % lipid energy) or a high-fructose diet (65 % fructose energy) for 10 weeks. BW, body fat mass ((2)H2O dilution method), IS (euglycaemic-hyperinsulinaemic clamp technique), plasma glucose, insulin, NEFA, TAG and total cholesterol were assessed before and at the end of 10-week period. Cholesterol was measured in plasma lipoproteins separated from pooled samples of each group and each time period by using fast-protein liquid chromatography. All rats had similar BW at the end of the 10-week period. Body fat mass was higher in the high-fat group compared to the control group. There was no change in basal glycaemia and insulinaemia. The IS was lower in the high-fat group and was unchanged in the high-fructose group, compared to the control group. Plasma TAG concentration and cholesterol distribution in lipoproteins did not change over time in any group. Plasma NEFA concentration decreased, whereas plasma TAG concentration increased over time, regardless of the diet in both cases. The 10-week high-fat diet led to obesity and low IS, whereas rats fed with the high-fructose diet exhibited no change in IS and lipidaemia. The high-fat diet had more deleterious response than high-fructose diet to induce obesity and low IS in rats.     

The effect of propoxur on rats fed diets differing in protein content

In 6-week-old Wistar rats fed for 30 and 93 days either 4.5 or 26% casein diets containing 0, 500, 1500, 4500, and 9000 ppm of propoxur several biological changes were found which were more pronounced when propoxur was added to low-protein diet for 93 days, particularly in concentrations of 4500 and 9000 ppm. The changes were as follows. (1) In the liver—decreased activity of aromatic amino acids aminotransferases (AAA) and β-glucuronidase (β-GR) as well as diminished protein content in supernatant; unchanged activity of aspartate aminotransferase (AspAT), glucosephosphate isomerase (PHI) and fructosediphosphate aldolase (ALD). (2) In the serum—decreased activity of acetylcholinesterase (AChE) as well as β-GR and increased PHI activity; unaltered activity of ALD and sorbitol dehydrogenase, (SDH). (3) In the brain—decreased activity of AChE, PHI, ALD, AAA, reduced protein content in supernatant; unchanged activity of AspAT and biogenic amines level. (4) Decreased rate of rat body weight gain on contaminated normoprotein diet and weight loss on contaminated low-protein diet. (5) Changes in the relative weight of certain internal organs; no detectable anatomical changes in the examined organs. The acute oral toxicity of propoxur was definitely enhanced by the previous feeding of low-protein diet: 1.7 times in males and 1.3 times in females after 30 days, and after 93 days 4.3 and 2.7 times, respectively.     

The effect of iron and zinc supplementation and its discontinuation on liver antioxidant status in rats fed deficient diets

Purpose

The aim was to investigate the effect of iron or combined iron/zinc supplementation on rat liver antioxidant status.

Methods

The 6-week male Wistar rats were examined in 3 stages: (1) 4-week adaptation to the diets (C—control AIN-93M diet, D—iron deficient and R—with 50 % reduction in all vitamin and mineral amounts); (2) 4-week supplementation with the same regimen enriched with tenfold more iron or iron/zinc; (3) 2-week post-supplementation period (the same diets as in the stage I).

Results

Combined iron/zinc supplementation similarly to iron supplementation alone significantly (p values ≤ 0.05) increased the iron content in the liver in D and R rats after stages II and III. Moreover, iron/zinc supplementation compared to iron supplementation alone significantly decreased the liver concentration of 8-isoprostane (after stage II in D and after stage III in R rats), protein carbonyl groups (only after stage III in R rats) and 8-hydroxy-2-deoxyguanosine (after stage II in R and after stage III in D and R rats). In rats fed R-type of diets after stage II hepatic superoxide dismutase (SOD) and catalase (CAT) activity, but not glutathione peroxidation activity and total antioxidant capacity, was lower in iron and iron/zinc supplemented than in non-supplemented rats, whereas after stage III in iron/zinc supplemented SOD was lower and CAT activity was higher in comparison with non-supplemented and iron supplemented rats.

Conclusions

The simultaneous iron/zinc supplementation can protect liver against peroxidative damage induced by high doses of iron during and after the intervention in rats fed iron-deficient diet and diet with reduced amounts of vitamins and minerals. The post-intervention observation is relevant because the effect may be delayed and visible only after this period.     

复配式粗杂粮对胰岛素抵抗大鼠LCN-2表达影响

目的 探讨全谷豆复配式粗杂粮对高脂膳食诱导胰岛素抵抗大鼠肝脏和脂肪组织中载脂蛋白2(LCN-2)影响.方法 40只雄性SD大鼠随机分为阴性对照组、高脂模型组、米面组和粗杂粮组,以相应饲料连续喂养8周,测定各组大鼠血清空腹血糖(FBG)和胰岛素(FINS)水平,并计算胰岛素抵抗指数(HOMA-IR);Westernblotting检测各组大鼠肝脏和脂肪组织中LCN-2和过氧化物酶体增殖体激活受体-γ(PPAR-γ)蛋白表达.结果 与阴性对照组比较,高脂模型组和米面组血清FBG和FINS水平明显升高(P<0.05).高脂模型组和米面组HOMA-IR分别为(10.39±1.63)和(10.34±1.36),明显高于阴性对照组(6.85±1.33);与高脂模型组和米面组比较,粗杂粮组HOMA-IR(6.81±1.37)明显下降,粗杂粮组LCN-2在肝脏和脂肪组织中表达明显低于高脂模型组和米面组,PPAR-γ则相反.结论 全谷豆复配式粗杂粮可以激活胰岛素抵抗大鼠PPAR-γ蛋白,进而降低脂肪因子LCN-2表达,改善胰岛素敏感性.     

Myocardial stereological adaptations in wistar rats fed with different high-fat diets during 18 months

This study has the purpose of investigating the influence of different high-fat experimental diets on myocardial structure in rats. Twenty-seven male rats were fed from 21 d old (postnatal age) until 18 mo old with one of the following supplemented diets: soybean oil (S) (n= 6), canola oil (CA) (n= 8), or lard and egg yolk (LE) (n= 6) or canola oil+ lard and egg yolk (CA+LE) (n=7). The blood pressure (BP) was measured, and after the sacrifice the cardiac biometry and the myocardial stereology were determined: cross-sectional area of cardiomyocyte (A), volume density (Vv), surface density (Sv), and length density (Lv) in relation to the cardiomyocytes (cm), connective tissue (ct), and blood vessels (v). The CA group rats had lower BP, A[cm], and Vv[ct]; they had greater Vv[cm], Sv[cm], Vv[v], Lv[v], and Sv[v] than the other groups. The S rats had intermediary values for the myocardium and blood vessel parameters between the CA and LE group rats. These results support the notion that the long-term use of canola oil in the diet is better to preserve the myocardium structure, including microvascularization, than soybean oil or lard and egg yolk.     

Heart and blood pressure adaptations in Wistar rats fed with different high-fat diets for 18 months

OBJECTIVE: We investigated the effect of long-term administration of four different high-fat diets on systolic blood pressure (SBP), body and heart biometry, and left ventricular myocyte nuclei number (N[lvm]). METHODS: Twenty-four Wistar rats were assigned to one of four groups from weaning to age 18 mo. The rats were fed experimental diets containing soybean oil (S group), canola oil (CA group), lard and egg yolk (LE group), and canola oil plus lard and egg yolk (CA + LE group). N(lvm) was measured with the disector method in isotropic uniform random sections of the left ventricular myocardium. RESULTS: There were no significant differences across experimental groups in morphometric indices. SBP was higher in the LE group at all ages and lower in the 18-mo CA group. The myocardium structure analysis separated the animals in three major categories: the CA and LE groups as the extreme and the S and CA + LE groups as the intermediary. In the LE group the myocardium presented more important structural changes: cardiac myocytes were enlarged and surrounded with thick collagen bundles, and some regions exhibited myocardial necrosis. CONCLUSION: Long-term intake of the CA diet was more efficient in maintaining normal N(lvm) and SBP than the S and LE diets. The CA + LE diet resulted in balanced levels of SBP and N(lvm) in rats, suggesting that canola oil reduces cardiovascular injury caused by intake of lard and egg yolk.     

Soybean protein hydrolysate improves plasma and liver lipid profiles in rats fed high-cholesterol diet

OBJECTIVE: This investigation attempted to clarify the hypolipidemic effects of non-dialyzed soybean protein hydrolysate (NSPH), which is hydrolyzed by pepsin from soybean acid-precipitated protein (APP), in rats fed a cholesterol-rich diet. METHODS: Forty Sprague-Dawley rats were divided into four groups as the control group (19.7% casein), the APP group (14.7% casein + 5% APP), the NSPH group (14.7% casein + 5% NSPH), and the ISO group (19.7% casein + 0.0013% soy isoflavone). RESULTS: After 12-week experimental period, the APP and NSPH groups had a significant lower plasma total cholesterol, triglycerides, and LDL-cholesterol concentrations compared with the control group. Additionally, the atherosclerosis index in APP and NSPH group had also markedly decreased. Liver cholesterol and triglyceride contents of the APP and NSPH group were significantly lower than those of the control group. There were no different in plasma LDL-C, liver cholesterol and triglycerides between the ISO group and control group. Fecal excretion of neutral steroids and nitrogen compounds was significantly higher in the APP and NSPH groups than that in the control group. An in vitro study also showed that NSPH, compared with casein, obviously decreased cholesterol micellar solubility. CONCLUSION: These results suggested that NSPH may decrease lipid accumulation in the liver and have a hypolipidemic effect by enhancing excretion and inhibiting absorption of lipids.     

高脂饮食大鼠脂肪组织SOCS-3及FAS表达

目的研究高脂饮食诱导产生的肥胖及肥胖抵抗大鼠脂肪组织细胞因子信号转导抑制因子-3(SOCS-3)及脂肪酸合成酶(FAS)的mRNA表达情况。方法Wistar雄性大鼠31只,其中7只喂饲普通基础饲料作为对照组;24只喂饲高脂饲料,第8周末,按体重增量从高脂饲料组筛选出5只大鼠作为肥胖组,5只大鼠作为肥胖抵抗组。测定血清甘油三酯和总胆固醇,检测附睾脂肪组织SOCS-3及FAS的mRNA表达。结果肥胖组大鼠血清甘油三酯及总胆固醇水平分别为(0.982±0.228),(2.213±0.364)mmol/L,均显著高于对照组大鼠的(0.717±0.153),(1.784±0.175)mmol/L(P<0.05),总胆固醇水平也显著高于肥胖抵抗组的(1.711±0.190)mmol/L(P<0.05);肥胖组大鼠的SOCS-3及FASmRNA表达水平均显著高于对照组和肥胖抵抗组(P<0.05)。结论高脂饮食诱导产生的肥胖和肥胖抵抗大鼠在基因表达调控上可能存在差异,肥胖大鼠的生脂能力增强并可能存在瘦素信号转导通路的抑制。     

Serum and liver lipids in rats and chicks fed with diets containing different oils

OBJECTIVES: Because dietary fat composition is determinant for serum cholesterol level, which is related to cardiovascular disease, we evaluated the effects of diets containing saturated (coconut oil) or polyunsaturated fatty acids (soybean oil) supplemented or not with dietary cholesterol on serum and liver lipid composition in two animal species. METHODS: Male Wistar rats (21 d old) were assigned to one of seven groups and fed with commercial diet or diets containing 5% or 20% soybean oil or 20% coconut oil with or without 1% cholesterol. Chicks were assigned to one of four groups and fed with diets containing 15% soybean oil or 15% coconut oil with or without 1% cholesterol. RESULTS: In rats, the accumulations of hepatic cholesterol and triacylglycerols were higher in the group fed 20% soybean oil and 1% cholesterol than in the group fed 20% coconut fat and 1% cholesterol. The highest serum levels of cholesterol and triacylglycerols were observed in the group fed coconut oil and cholesterol, compared with the group fed soybean oil and cholesterol. Triacylglycerol, high-density lipoprotein, and total cholesterol serum levels increased with diet containing coconut oil and cholesterol. In chicks, the highest hepatic cholesterol accumulation occurred in the group fed 15% coconut fat and 1% cholesterol. Total and high-density lipoprotein cholesterol levels increased with diet containing coconut oil and cholesterol, although none of these diets modified serum triacylglycerol levels. CONCLUSIONS: The type of experimental animal model and the diet composition influence lipid metabolism.     

Effect of thioacetamide and dexamethasone on serum lipids in rats fed on high-fat sunflower or olive oil diets.

We have previously reported that high-fat diets develop hepatic steatosis and, depending on the fat quality, affect serum lipid levels differently (J Nutr Sci Vitaminol, 1997, 43, 155-160). The aim of this work is to study the influence of high-fat diets (14% sunflower or olive oils) on serum lipids in a model of hepatic acute damage induced by thioacetamide, and their influence when dexamethasone is administered before thioacetamide injection. Serum lipids and hepatic collagen have been evaluated using biochemical methods, and the steatotic process by histological staining. The results showed that hepatic steatosis and fibrosis are developed either by high-fat diets or thioacetamide injection. Pretreatment with dexamethasone did not decrease the hepatic collagen content. Thioacetamide injection alone or pretreatment with dexamethasone produced increase in serum tryglicerides (TG), total cholesterol (TC) and LDL-C in both high-fat diet groups, and a HDL-C increase in the olive-oil group, even though the atherogenic indices (HDL/TC and HDL/TG) were different depending on the enriched diet. The administration of high-fat diets to study the influence of the fat quality on health and disease should be interpreted carefully due to the ability of the diets themselves to cause hepatic damage.     

Fermented barley extracts with Lactobacillus plantarum dy-1 changes serum metabolomic profiles in rats with high-fat diet-induced obesity

We have previously reported an aqueous extract of fermented barley with Lactobacillus plantarum dy-1 (LFBE) has more efficient anti-obesity effect compared with that of Saccharomyces cerevisiae. To further explore associated effects of LFBE on body weight and body fat distribution, and lipid profiles related metabolic outcomes, serum metabolites were analysed using LC-MS-MS and partial least-squares-discriminant analysis (PLS-DA). Obese and lean groups were clearly discriminated from each other on PLS-DA score plot and major metabolites contributing to the discrimination were assigned as lipid metabolites (fatty acids), lipid metabolism intermediates (choline, betaine, carnitine and butyryl-carnitine), amino acids and citric acid. A high-fat diet increased lipid metabolites and decreased lipid metabolism intermediates, indicating that abnormal lipid metabolism induced by a high-fat diet resulted in fat accumulation via decreased β-oxidation. But LFBE can inhibit fat accumulation by reducing lipid metabolites and increasing lipid metabolism intermediates. Furthermore, the level changes of these metabolites can be used to assess the risk of obesity and the therapeutic effect of obesity management.     

Influence of carbohydrate and fat intake on diet-induced thermogenesis and brown fat activity in rats fed low protein diets

Voluntary intake of protein, fat and carbohydrate (CHO) was modified by feeding young rats either a control purified diet [% metabolizable energy (ME): protein 21, fat 7, CHO 72], a control diet plus sucrose solution (20%) to drink (final intakes 17, 6 and 77% ME as protein, fat and CHO, respectively) or a low protein diet substituted with either CHO (8, 7 and 85% ME as protein, fat and CHO, respectively) or fat (8, 20 and 72% ME as protein, fat and CHO, respectively). Total ME intakes corrected for body size were similar for all rats, but body weight, energy gain and net energetic efficiency were lower in both low protein-fed groups than in the control group. The acute thermogenic response (% rise in oxygen consumption) to a standard balanced-nutrient meal was higher (12%) in sucrose-supplemented and in low protein groups (15-16%) than in control rats (8%). Brown adipose tissue protein content and thermogenic capacity (assessed from purine nucleotide binding to isolated mitochondria) were greater than control values in sucrose-fed and protein-deficient animals, and the greatest levels of activity were seen in low protein-fed rats with a high fat intake. The results demonstrate that the changes in energy balance, thermogenesis and brown adipose tissue activity that result from protein deficiency cannot be ascribed to changes in the level of energy intake or to a specific increase in the amount or proportion of either CHO or fat. They suggest that the protein-to-energy ratio must be the primary influence on thermogenesis and brown fat activity in these animals.     

Effect of exogenous ascorbic acid on experimental hypertension and mineral balance in rats fed low- and high-fat diets.

The effects of exogenous ascorbic acid on the development of experimental hypertension and on calcium, sodium, and potassium metabolism have been studied. The investigation was carried out in 90 4-mo-old male Wistar rats fed high- and low-fat diets. Hypertension was induced by administering a 1.5% solution of NaCl orally. Some rats received 0.1% ascorbic acid in distilled water orally for the first 7 wk of the experiment, then 0.3% for the next 5 wk. The results showed that the amount of fat, NaCl, and ascorbate in the diet may play a role in the etiopathogenesis of hypertension. A high-fat high-NaCl diet increased blood pressure more than a low-fat high-NaCl diet. Additional intake of 0.3% ascorbate solution reduced experimentally induced hypertension by 4% with a low-fat diet and by 14% with a high-fat diet. Also, 0.3% ascorbate solution had a blood-pressure-lowering effect in rats fed a high-fat diet without NaCl. Supplementation with ascorbate diminished urine calcium output with a high-fat diet and increased the urine PGE2/PGF2 ratio with both low- and high-fat diets.     

Altered lactational performance in rats fed low carbohydrate diets and its effect on growth of neonatal rat pups

The possibility that low carbohydrate diets fed to nursing rat dams altered milk composition and impaired neonatal growth and development was explored. Pregnant control dams fed a 62% glucose diet were paired at parturition with experimental dams fed diets with either severe (0% glucose) or moderate (6% glucose) carbohydrate restriction. At birth half of the littermates of each pair were cross-fostered so that each dam nursed a litter consisting of one-half deficient and one-half control pups. All pups born to dams fed the 0% glucose diet died within 24 h of birth whether they were nursed by control or deficient dams. Control pups cross-fostered to these deficient dams died by the second day; the 0% glucose diet failed to support milk production. In contrast, the dams fed the 6% glucose diet produced milk, but its composition was significantly lower in carbohydrate and lipid than was milk of control dams. This altered milk composition was associated with retarded postnatal growth and development. Control pups cross-fostered to 6% glucose dams showed decreased survival (83% vs. 97%) and significantly reduced body weight (10 g vs. 12 g) at d 7. Conversely, 6% glucose pups cross-fostered to control dams showed improved survival (54% vs. 29%) and significantly increased body weight (9 g vs. 7 g) at d 7. These data showed that carbohydrate-restricted diets altered milk production and/or composition, which, in turn, reduced growth and increased mortality in the pups nursed by dams fed these diets. The results demonstrate that an adequate source of dietary carbohydrate is important for optimal lactational performance.     

Effects of simultaneous intakes of indigestible dextrin and diacylglycerol on lipid profiles in rats fed cholesterol diets

OBJECTIVE: Indigestible dextrin (IDex) and diacylglycerol (DG) are food components with physiologic effects on lipid metabolism. Because simultaneous intake of dietary components with similar physiologic functions may produce a beneficial decrease in risk factors for lifestyle-related diseases, we investigated the physiologic effects of simultaneous IDex and DG intake. METHODS: Five-week-old male Wistar rats were fed a cholesterol-containing diet with IDex and DG (separately and combined) for 28 d. RESULTS: IDex significantly decreased serum triacylglycerol concentration and increased the length of small intestinal villi, whereas DG produced significant decreases in serum high-density lipoprotein cholesterol concentration and significant increases in liver cholesterol and triacylglycerol concentrations. CONCLUSIONS: IDex intake characteristically decreased serum triacylglycerol concentrations, although no additive or synergistic interaction between DG and IDex was observed. These results indicate that simultaneous intake of food components with similar physiologic functions do not necessarily produce additive or synergistic physiologic benefits.     

Resveratrol up-regulates hepatic uncoupling protein 2 and prevents development of nonalcoholic fatty liver disease in rats fed a high-fat diet

Obesity is associated with a markedly increased risk of nonalcoholic fatty liver disease. The anti-inflammatory polyphenol resveratrol possess promising properties in preventing this metabolic condition by dampening the pathological inflammatory reaction in the hepatic tissue. However, in the current study, we hypothesize that the beneficial effect of resveratrol is not solely attributable to its anti-inflammatory potential. Eight-week-old male Wistar rats were randomly distributed into 3 groups of 12 animals each: control diet (C), high-fat diet (HF), and HF supplemented with 100 mg resveratrol daily (HFR). After 8 weeks of dietary treatment, the rats were euthanized and relevant tissues were prepared for subsequent analysis. Resveratrol prevented the high fat–induced steatosis assessed by semiquantitative grading, which furthermore corresponded with a complete normalization of the hepatic triglyceride content (P < .001), despite no change in total body fat. In HFR, the hepatic uncoupling protein 2 expression was significantly increased by 76% and 298% as compared with HF and C, respectively. Moreover, the hepatic mitochondria content in HFR was significantly higher as compared with both C and HF (P < .001 and P = .004, respectively). We found no signs of hepatic inflammation, hereby demonstrating that resveratrol protects against fatty liver disease independently of its proposed anti-inflammatory potential. Our data might indicate that an increased number of mitochondria and, particularly, an increase in hepatic uncoupling protein 2 expression are involved in normalizing the hepatic fat content due to resveratrol supplementation in rodents fed a high-fat diet.     

Yerba Mate (Ilex paraguariensis) modulates NF-kappaB pathway and AKT expression in the liver of rats fed on a high-fat diet

To investigate the effect of Yerba Mate (YM) aqueous extract intake on the NF-kB pathway and AKT expression in the liver, muscle, and adipose tissue of rats submitted to a high-fat diet (HFD). Male Wistar rats were fed a control (CON) (n?=?24) or a HFD (n?=?24) for 12 weeks. Afterwards, rats received YM daily (1?g/kg body weight) for 4 weeks. Intake of YM aqueous extract reduced body weight gain (p?p?相似文献