Changes in lipid metabolism and antioxidant defense status in spontaneously hypertensive rats and Wistar rats fed a diet enriched with fructose and saturated fatty acids

OBJECTIVE: Larger doses of fructose and saturated fat have been associated with oxidative stress and development of hypertension. The effects of modest amounts of fructose and saturated fatty acids on oxidative stress are unknown. METHODS: To increase knowledge on this question, 10-wk-old spontaneously hypertensive rats and Wistar rats were fed for 8 wk with a control diet or an experimental diet enriched with fructose (18%) and saturated fatty acids (11%; FS diet). The total antioxidant status of organs and red blood cells was assayed by monitoring the rate of free radical-induced red blood cell hemolysis. Sensitivity of very low-density lipoprotein and low-density lipoprotein (VLDL-LDL) to copper-induced lipid peroxidation was determined as the production of thiobarbituric acid-reactive substances. Antioxidant enzymes and vitamins were also measured to establish the oxidative stress effect. RESULTS: The FS diet did not affect blood pressure in either strain, but it increased plasma insulin concentrations only in Wistar rats without affecting those of glucose of either strain. The FS diet significantly enhanced plasma and VLDL-LDL triacylglycerol concentrations without affecting concentrations of VLDL-LDL thiobarbituric acid-reactive substances. The decreased content of arachidonic acid and total polyunsaturated fatty acids in VLDL-LDL by the FS diet may have prevented lipid peroxidation in this fraction. Moreover, FS consumption by both strains was accompanied by a significant increase in total antioxidant capacity of adipose tissue, muscle, heart, and liver. This may have resulted from increased tissue ascorbic acid levels and glutathione peroxidase and glutathione reductase activities in tissues. CONCLUSIONS: These findings clearly indicate that the FS diet did not alter blood pressure of spontaneously hypertensive rats and Wistar rats. The FS diet resulted in hypertriglyceridemia but increased the total antioxidant status, which may prevent lipid peroxidation in these rats.     

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.     

Effects of megadoses of dietary vitamin E on the antioxidant status of rats fed lard or salmon oil

This study was undertaken to investigate whether megadoses of vitamin E in the diet of rats can have pro-oxidative activity. Two experiments with rats were conducted in which both the dietary vitamin E concentration (Experiment 1: 100; 500; 3000; 10,000 mg all-rac-alpha-tocopheryl acetate/kg, and Experiment 2: 100; 1000; 10,000 mg all-rac-alpha-tocopheryl acetate/kg) and the type of dietary fat (lard vs. salmon oil) were varied. Experimental parameters were the concentrations of thiobarbituric acid-reactive substances, 7 beta-hydroxycholesterol, the activities of several antioxidative enzymes, the concentration of glutathione in the liver, and the lag time during copper-induced low-density lipoprotein (LDL) oxidation. Increasing the dietary vitamin E concentration to 10,000 mg all-rac-alpha-tocopheryl acetate/kg led to a significant reduction of thiobarbituric acid-reactive substances in the liver after feeding salmon oil, and also to a significant reduction in 7 beta-hydroxycholesterol after feeding both dietary fats. Megadoses of vitamin E (3000 and 10,000 mg all-rac-alpha-tocopheryl acetate/kg) also led to a reduction in the activity of superoxide dismutase and the concentration of glutathione in the liver of rats fed salmon oil. The lag time during LDL oxidation was independent of the dietary vitamin E concentration. The study shows that megadoses of vitamin E, far from having pro-oxidative activity, actually increase the anti-oxidative capacity of the liver, especially after ingestion of salmon oil.     

Effects of capsaicin on lipid metabolism in rats fed a high fat diet

Effects of capsaicin, a pungent principle of hot red pepper, were studied in experiments using male rats fed a diet containing 30% lard. Capsaicin was supplemented at 0.014% of the diet. The level of serum triglyceride was lower when capsaicin was present in the diet than when it was not. Levels of serum cholesterol and pre-beta-lipoprotein were not affected by the supplementation of capsaicin. The perirenal adipose tissue weight was lower when capsaicin was present in the diet than when it was not. Hepatic enzyme activities of glucose-6-phosphate dehydrogenase and adipose lipoprotein lipase were lower in rats fed the 30% lard diet than in those fed a nonpurified diet. Activities of these two enzymes were higher when capsaicin was added to the diet than when it was not. Hepatic acetyl-CoA carboxylase, beta-hydroxyacyl-CoA dehydrogenase, and adipose hormone-sensitive lipase activities were not affected by capsaicin feeding. Lipid absorption was not affected by the supplementation of capsaicin. The perirenal adipose tissue weight and serum triglyceride were decreased as the level of capsaicin in the diet increased up to 0.021%. These results suggest that capsaicin stimulates lipid mobilization from adipose tissue and lowers the perirenal adipose tissue weight and serum triglyceride concentration in lard-fed rats.     

Effects of solid-state fermented rice on lipid metabolism and antioxidant status in high-cholesterol-fed rats

We investigated the effect of solid-state fermented rice cultured with Basidiomycota (sangwhang) and Monascus ruber on lipid metabolism and antioxidant activity. Forty 4-week-old male Sprague-Dawley rats were fed high cholesterol diets in which carbohydrate sources in the treatment groups consisted of non-fermented rice and sangwhang or M. ruber rice at 80% and 20%, respectively, for 5 weeks. Supplementation with sangwhang and M. ruber rice had no effect on growth and food intakes in high-cholesterol-fed rats. The plasma triglyceride concentration was not significantly different among the groups. Supplementation with M. ruber rice resulted in lower plasma and hepatic cholesterol concentrations and atherogenic index compared to the control group, while the plasma high-density lipoprotein-cholesterol concentration was elevated. In addition, fermented rice cultured with M. ruber-supplemented animals had greater bile acid excretion. The M. ruber groups had significantly lower plasma and hepatic levels of thiobarbituric acid-reactive substances than the control group. Moreover, hepatic antioxidant enzyme activities, including catalase and superoxide dismutase, were significantly higher in the M. ruber group. In conclusion, fermented rice, especially M. ruber rice, was very effective for improving the lipid metabolism and reducing oxidative stress by up-regulating the hepatic antioxidant enzymes in high-cholesterol-fed rats.     

Effect of free plant sterols in low-fat milk on serum lipid profile in hypercholesterolemic subjects

OBJECTIVE: To determine the effect of nonesterified, nonhydrogenated plant sterols solubilized in a partly vegetable oil-filled low-fat milk on serum low-density lipoprotein cholesterol (LDL) in mildly hypercholesterolemic patients. DESIGN: Double-blind, randomized, placebo-controlled three-arm crossover study. SETTING: Outpatient clinical trial. SUBJECTS: A total of 138 patients were screened, providing 81 patients for randomization; 71 patients completed the study. INTERVENTIONS: The study product was a 500 ml milk blend with or without nonesterified, nonhydrogenated sterols. The daily consumption of sterols in the three groups was 0 g/day, control group (C); 1.2 g/day, (Lo); or 1.6 g/day, (Hi), respectively. The patients were randomly assigned to one of three different treatment sequences. Each intervention period was 4 weeks. The total study duration was 12 weeks. RESULTS: The milk product was well tolerated. The placebo-adjusted mean reduction in LDL was 7.13+/-12.31 and 9.59+/-12.44% (mean+/-s.d.) for Lo and Hi groups, respectively (P<0.0001); there was no statistically significant difference in LDL lowering for the Lo and Hi groups. There were no significant changes in serum vitamin E or carotenoid concentrations after standardization with LDL cholesterol during the study period. CONCLUSION: The present study shows for the first time a substantial reduction in LDL cholesterol with a new, partly vegetable oil-filled 1.2% low-fat milk product, containing nonesterified plant sterols from soybean oil, in a randomized, placebo-controlled trial. This result encourages further development of novel low-fat dairy products containing free plant sterols for future use in cholesterol-lowering initiatives.     

Effects of 2 or 5 consecutive exercise days on adipocyte area and lipid parameters in Wistar rats

Background  

Exercise has been prescribed in the treatment and control of dyslipidemias and cholesterolemia, however, lipid responses to different training frequencies in hypercholesterolemic men have been inconsistent. We sought to verify if different frequencies of continuous moderate exercise (2 or 5 days/week, swimming) can, after 8 weeks, promote adaptations in adipocyte area and lipid parameters, as well as body weight and relative weight of tissues in normo and hypercholesterolemic adult male rats.     

食用竹炭粉对高脂模型大鼠脂肪代谢的影响

目的探讨食用竹炭粉(bamboo charcoal powder,BCP)对高脂模型大鼠的降脂作用及其机制。方法 4周龄SPF级雄性SD大鼠,随机分成5组:空白对照组,高脂模型对照组和BCP低、中、高剂量(2.81、5.62、11.24 g/kg)干预组。各组每日灌胃相应剂量的竹炭粉或蒸馏水,连续90 d。股动脉取血测定肝肾功能等生化指标;取肝、肾及双侧肾脏及附睾周围的脂肪称重;取左侧肝叶做组织病理学检查;制备肝匀浆,检测总胆固醇(TC)、甘油三酯(TG)、总抗氧化能力(T-AOC)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)和丙二醛(MDA)含量。结果从第4周起高脂模型对照组体重显著高于同期空白对照组,同时高脂模型对照组脂/体比、血清谷丙转氨酶(ALT)、TG和极低密度脂蛋白(VLDL)均高于空白对照组;高脂模型对照组肝脏可观察到明显的脂肪变性,肝脏中MDA、TC和TG含量均高于空白对照组,表明造模成功。BCP各剂量组与高脂模型对照组比较,体重、肝重及脂/体比均明显降低,血清ALT、TG和VLDL浓度降低,肝脏脂肪变性程度减轻,同时肝脏中TC和MDA浓度也均降低,T-AOC、SOD和CAT活性升高。结论食用竹炭粉具有减少高脂模型大鼠体内脂肪蓄积、降血脂、减轻肝脏脂肪变性的作用,其机制可能与减轻体内脂质过氧化作用有关。     

Effects of high magnesium intake on bone mineral status and lipid metabolism in rats

Effects of magnesium (Mg)-intake on mineral levels in bone, blood and various tissues, bone density and plasma lipids were examined in 4-wk-old, female Wistar rats fed diets of five different Mg-contents of 1/10, 1 (standard diet (Mg 47 mg/100 g diet): control group), 2, 5 and 10-fold of the standard content for 4 wk. In rats fed the 1/10-fold Mg diet, the body weight gain declined with a statistical significance compared to control rats, while no significant differences were observed in rats fed on the 2-, 5-, and 10-fold Mg diets. The imbalance of mineral concentrations in the rats fed 1/10 Mg diet was induced, but in the rats fed high Mg diets were not induced except in tibia. Mg concentration in tibia of rats fed the 10-fold Mg diet significantly increased compared to the control group. All groups (1/10-fold, 2-, 5-, and 10-fold Mg groups) showed no significant changes in tibial mineral levels, except Mg in the 10-fold group, compared to the control group. With increase in Mg-intake, decline of plasma lipid parameters such as cholesterol, triglycerides and phospholipids are induced. Based on these results, it was suggested that a higher Mg-intake (around 5-fold of the standard Mg-content) might have a prophylactic potential against the onset of hyperlipidemia and cardiovascular disease by reducing lipid indices, and Mg decline in bone.     

菰米对高脂诱导脂代谢紊乱大鼠肝脏脂毒性的作用

目的观察由米面和菰米等不同构成饲料对高脂饲料大鼠血脂、游离脂肪酸(FFA)和瘦素(leptin)水平的作用,探讨菰米对高脂饲料诱导的脂代谢紊乱大鼠血脂及肝脏脂毒性的作用。方法 44只雄性SD大鼠随机分为阴性对照组、高脂模型组、米面组和菰米组;以相应饲料连续喂养8周,测定各组大鼠体重、血清总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)、FFA和leptin等指标,同时肝脏组织行病理切片检查。结果与阴性对照组相比,高脂模型组和米面组大鼠的血清TC、TG、FFA和leptin水平显著上升(P<0.05),HDL-C水平显著降低(P<0.05),肝脏发生脂肪变性;与高脂模型组和米面组相比,菰米组大鼠的血清TC、TG、FFA水平显著下降(P<0.05),HDL-C水平显著升高(P<0.05),leptin水平稍低于高脂模型组和米面组,但无显著性差异,肝脏脂肪变性程度显著减轻。结论菰米具有降低高脂饲料诱导的脂代谢紊乱大鼠血脂水平和肝脏脂毒性的作用。     

Effect of low-fat, fermented milk enriched with plant sterols on serum lipid profile and oxidative stress in moderate hypercholesterolemia

BACKGROUND: Plant sterol (PS)-enriched foods have been shown to reduce plasma LDL-cholesterol concentrations. In most studies, however, PSs were incorporated into food products of high fat content. OBJECTIVE: We examined the effect of daily consumption of PS-supplemented low-fat fermented milk (FM) on the plasma lipid profile and on systemic oxidative stress in hypercholesterolemic subjects. DESIGN: Hypercholesterolemic subjects (LDL-cholesterol concentrations >or=130 and 相似文献   

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.     

Effects of anthocyanin-rich purple potato flakes on antioxidant status in F344 rats fed a cholesterol-rich diet

We examined the antioxidant effects of polyphenol/anthocyanin-rich potato (Solanum tuberosum cv. Shadow-Queen) flakes in male rats fed a high-cholesterol diet. The rats were served either a high-cholesterol (0.5% cholesterol plus 0.125% sodium cholate) diet, or a high-cholesterol diet containing a mixture of 243 g alpha-maize starch/kg supplemented with one of the following (per kg diet): 300 g medium purple potato (Shadow-Queen), 300 g white potato (Solanum tuberosum cv. Toyoshiro) or 300 g dark purple sweet potato (Ipomoea batatas cv. Ayamurasaki) flakes for 28 d. We analysed thiobarbituric acid reactive substance (TBARS) levels in the serum and liver, and antioxidant enzyme activities in the liver. At this dosage, TBARS levels in the serum and liver of the Shadow-Queen and Ayamurasaki groups were significantly lower than those in the control and Toyoshiro groups. The serum urate levels in all the flake groups were significantly lower than that in the control group. The hepatic glutathione levels in the Shadow-Queen and Ayamurasaki groups were significantly higher than in the control and Toyoshiro groups. The activities of hepatic glutathione reductase and glutathione S-transferase in the Shadow-Queen and Ayamurasaki groups were significantly greater than those in the control group. These results show that modulation of antioxidant enzymes and oxidative status in the serum and liver by the purple potato flake diet (Shadow-Queen) containing polyphenols/anthocyanins may play an important role in the protection against adverse effects related to oxidative damage in rats fed a high-cholesterol diet.     

褪黑素对低硒饮食大鼠脂质过氧化的影响

目的 :研究褪黑素对低硒粮喂养的大鼠脂质过氧化增强的影响 ,并讨论其可能机制。方法 :将SD大鼠分为 3组 ,分别用低硒饲料、低硒饲料加硒、低硒饲料加褪黑素灌胃饲养 ,12周时检测血Se、血GSH—Px及心肌组织、肝组织匀浆MDA水平。结果 :12周时低硒组大鼠血Se、GSH—Px较加硒组 (对照组 )显著降低 ,心肌组织、肝组织匀浆MDA均明显高于其它两组。加硒组与褪黑素组MDA无显著差异。结论 :褪黑素可以显著抑制低硒饮食大鼠脂质过氧化的增强 ,作用与其抗氧化机制有关     

Physical exercise affects the lipid profile of mitochondrial membranes in rats fed with virgin olive oil or sunflower oil.

The effects of physical exercise on the lipid profile in mitochondrial membranes of liver and skeletal muscle were examined in rats fed with virgin olive oil or sunflower oil. Thirty male Wistar rats, 21 d old, were randomly assigned to four groups according to fat ingestion and physical activity over an 8-week period. For each type of oil, one group acted as a control group while rats from the other were trained to run for 40 min daily on a horizontal treadmill, at a speed of 35 m/min. The results show that diet affected the fatty acid profile of the mitochondrial membranes from skeletal muscle and liver. Physical exercise also modified the fatty acid profile of the mitochondrial membranes. Total monounsaturated fatty acids decreased (P < 0.001) in liver mitochondria of exercised animals. Total polyunsaturated fatty acids in mitochondrial membranes of liver increased (P < 0.005) after exercise but those in mitochondrial membranes of skeletal muscle decreased (P < 0.05). These changes due to the exercise may arise via several mechanisms, e.g. fluidity regulation; changes in the eicosanoid metabolism; differences in the availability or oxidation rate of the different fatty acids.     

大豆蛋白对大鼠血脂代谢影响

目的 探讨大豆蛋白在普通饮食和高脂饮食状态下对大鼠血清脂质水平的影响及作用机制。方法 48只清洁级SD大鼠,按体重随机分为4组,分别喂饲含酪蛋白和大豆蛋白的普通饲料和高脂饲料28 d后,脱颈椎处死动物,检测血脂指标及基因表达水平。结果 大豆蛋白组大鼠血清胆固醇(TC)浓度(1.36±0.38)mmol/L,比酪蛋白组(1.97±0.42)mmol/L低31%(P<0.05);大豆蛋白高脂组大鼠血清TC、甘油三酯(TG)和低密度脂蛋白胆固醇(LDL-C)浓度分别为(1.43±0.22),(0.53±0.14)和(0.25±0.06)mmol/L,分别比酪蛋白高脂组(2.03±0.31),(0.79±0.20),(0.31±0.06)mmol/L降低30%,33%和19%(P<0.05)。大豆蛋白组大鼠肝脏3-羟基-3-甲基戊二酸辅酶A(HMG-CoA)还原酶及低密度脂蛋白受体(LDL-R)基因的表达均高于酪蛋白组。结论 大豆蛋白通过影响HMG-CoA还原酶及LDL-R基因的表达调节血脂水平。     

Influence of Piper betle on hepatic marker enzymes and tissue antioxidant status in ethanol-treated Wistar rats

Piper betle L. is a commonly used masticatory in Asia. This study was carried out to investigate the hepatoprotective and antioxidant properties of P. betle, using ethanol intoxication as a model of hepatotoxic and oxidative damage. Ethanol-treated rats exhibited elevation of hepatic marker enzymes and disturbances in antioxidant defense when compared with normal rats. Oral administration of P. betle extract (100, 200, or 300 mg/kg body weight) for 30 days significantly (P <.05) decreased aspartate aminotransferase (AST), alanine aminotransferase (ALT), thiobarbituric acid reactive substances (TBARS), and lipid hydroperoxides in ethanol treated rats. The extract also improved the tissue antioxidant status by increasing the levels of nonenzymatic antioxidants (reduced glutathione, vitamin C, and vitamin E) and the activities of free radical-detoxifying enzymes such as superoxide dismutase, catalase, and glutathione peroxidase in liver and kidney of ethanol-treated rats. The highest dose of P. betle extract (300 mg/kg body weight) was most effective. The results were comparable with the known hepatoprotective drug, silymarin. These results indicate that P. betle could afford a significant hepatoprotective and antioxidant effect.     

Reduced-calorie orange juice beverage with plant sterols lowers C-reactive protein concentrations and improves the lipid profile in human volunteers

BACKGROUND: Dietary plant sterols effectively reduce LDL cholesterol when incorporated into fat matrices. We showed previously that supplementation with orange juice containing plant sterols (2 g/d) significantly reduced LDL cholesterol. Inflammation is pivotal in atherosclerosis. High-sensitivity C-reactive protein (hs-CRP), the prototypic marker of inflammation, is a cardiovascular disease risk marker; however, there is a paucity of data on the effect of plant sterols on CRP concentrations. OBJECTIVE: The aim of this study was to examine whether plant sterols affect CRP concentrations and the lipoprotein profile when incorporated into a reduced-calorie (50 calories/240 mL) orange juice beverage. DESIGN: Seventy-two healthy subjects were randomly assigned to receive a reduced-calorie orange juice beverage either without (Placebo Bev) or with (1 g/240 mL; Sterol Bev) plant sterols twice a day with meals for 8 wk. Fasting blood was obtained at baseline and after 8 wk of Placebo Bev or Sterol Bev supplementation. RESULTS: Sterol Bev supplementation significantly reduced total cholesterol (5%; P < 0.01) and LDL cholesterol (9.4%; P < 0.001) compared with both baseline and Placebo Bev (P < 0.05). HDL cholesterol increased significantly with Sterol Bev (P < 0.02). No significant changes in triacylglycerol, glucose, or liver function tests were observed with Sterol Bev. Sterol Bev supplementation resulted in no significant change in vitamin E and carotenoid concentrations. Sterol Bev supplementation resulted in a significant reduction of CRP concentrations compared with baseline and Placebo Bev (median reduction: 12%; P < 0.005). CONCLUSION: Supplementation with a reduced-calorie orange juice beverage containing plant sterols is effective in reducing CRP and LDL cholesterol and could be incorporated into the dietary portion of therapeutic lifestyle changes.