Plasma Cholesterol Levels In Rats Research Articles

Effect of dietary Schizochytrium microalga oil and fish oil on plasma cholesterol level in rats.

The purpose of the study was to test the hypothesis that the dietary oils with different content of n-3 polyunsaturated fatty acids (PUFA) eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) affect plasma lipid level in rats in a different degree. The diets with 6% of fish oil (FO) and Schizochytrium microalga oil (SchO; EPA+DHA content in the diets 9.5+12.3 and 2.6+29.5% of the sum of total fatty acids, respectively) were used; the diet with 6% of safflower oil (high content of n-6 PUFA linoleic acid, 65.5%; EPA+DHA content 0.7+0.9%) was used as a control. The difference between FO and SchO was established only in the case of plasma triacylglycerol (TAG) level: plasma TAG of the FO-fed rats did not differ from the control rats (p>0.05), while SchO decreased (p<0.05) plasma TAG to 46% of the control. On the other hand, FO and SchO decreased (p<0.05) total plasma cholesterol (TC) in rats in the same extent, to 73% of the control. Regarding the underlying mechanisms for the TC decrease, both SchO and FO up-regulated hepatic Insig-1 gene (181 and 133% of the control; p<0.05), which tended (p=0.15 and p=0.19 respectively) to decrease the amount of hepatic nSREBP-2 protein (61 and 66% of the control). However, neither SchO nor FO influenced hepatic 3-hydroxy-3-methyl-glutaryl-CoA reductase gene expression (p>0.05); SchO (but not FO) increased (p<0.05) low-density lipoprotein receptor mRNA in the liver. It was concluded that the decrease of total plasma cholesterol might be caused by an increased cholesterol uptake from plasma into the cells (in the case of SchO), but also by other (in the present study not tested) mechanisms.

Effects of rice bran oil deodorizer distillate on plasma cholesterol levels in rats (829.23)

Rice bran oil deodorizer distillate (RBODD) is a byproduct in the refinement of rice oil. RBODD has received great interest as a potential health‐promoting product because it is a rich source of tocopherols and tocotrienols. Hypercholesterolemia is one of the major risk factors for coronary heart disease. The objective of this study was to investigate the effect of RBODD on plasma cholesterol concentrations in Sprague Dawley rats. Thirty three 6 week old rats were randomly divided into three groups: normal fat control (NFC), high fat control (HFC) and high fat diet plus RBODD treatment (RBO). 45 mg of RBODD was orally administered daily for 3 weeks into each treatment rat using 5% of Tween‐80 as a vehicle. The rats in the control groups were received Tween‐80 alone in the same manner. At the end of the feeding period, blood samples were collected by cardiac puncture for lipid analysis. RBO group had significantly lower plasma triglyceride compared with HFC group (p&lt;0.05). RBODD treatment did not show changes in the cholesterol levels. This study suggests that the efficacy of RBODD on plasma lipid profile is to improve triglyceride levels.Grant Funding Source: Supported by Arkansas Bioscience Institute (ABI)

The effect of sodium metabisulfite on visual evoked potentials in rats with hypercholesterolemia

This study aimed to investigate the effects of hypercholesterolemia on visual evoked potentials (VEPs) and sulfite additional effects. Rats were assigned as follows: control (C), sulfite (S), hypercholesterolemia (H), vitamin E (E), sulfite + vitamin E (SE), hypercholesterolemia + sulfite (HS), hypercholesterolemia + vitamin E (HE), and hypercholesterolemia + sulfite + vitamin E (HSE). Hypercholesterolemic diet led significant increase in plasma cholesterol levels of rats. Brain thiobarbituric acid reactive substances (TBARS) levels were significantly increased in S, E, SE, HE and HSE groups compared with C. TBARS levels were increased in HE and HSE groups as compared to HS group. Nitrite levels were decreased in S, SE, H, HS and HSE groups compared with C. Nitrite level was notably increased in the HE group compared with H group. Sulfite exposure prolonged N1 and P3 latencies of VEP in group S compared with C. Prolonged VEP latencies by sulfite were significantly decreased by vitamin E in SE group. Cholesterol rich diet increased VEP latencies in comparison with control latencies. Sulfite gave rise to an additional increase in P3 latency in HS group compared with H group. Vitamin E-treated animals had notably shortened latencies of VEP components in HE and HSE groups according to the H and HS groups, respectively.

Effect of Source and Level of Dietary Protein on Plasma Cholesterol Levels in Rats Fed a Diet Containing Cholesterol

Effect of Source and Level of Dietary Protein on Plasma Cholesterol Levels in Rats Fed a Diet Containing Cholesterol

Effect of Source and Level of Dietary Protein on Plasma Cholesterol Levels in Rats Fed a Diet Containing Butter or Margarin

Effect of Source and Level of Dietary Protein on Plasma Cholesterol Levels in Rats Fed a Diet Containing Butter or Margarin

Effects of Gender, Gonadectomy and Sex Hormones on Growth and Plasma Cholesterol Level in Rats

Background/Aims: No studies have clearly demonstrated how sex hormones are involved in the observed gender difference in growth and plasma cholesterol levels in animals fed hypercholesterolemic diets. This study was conducted to determine the effects of gender, gonadectomy (GNX), and sex hormones on growth, plasma cholesterol and cortisol levels in Sprague-Dawley rats. Methods: In the first of two experiments, equal numbers of male and female 4-week-old rats were divided into three groups: sham-operated control, GNX, or GNX + 17α-methyltestosterone (MT). The rats were fed a hypercholesterolemic diet for 4 weeks. In a second experiment, 24 GNX females were equally divided into three groups: control, 17β-estradiol (E₂), or MT. These rats were fed a normocholesterolemic diet for 3 weeks. Results: The average total plasma cholesterol level in female rats was twice that in male rats. MT administration to GNX male and GNX female rats decreased plasma cholesterol levels by 23 and 45%, respectively. Weekly intramuscular injection of E₂ markedly suppressed growth while increasing plasma cortisol levels in GNX female rats. Conclusion: Testosterone decreases plasma cholesterol levels in rats fed a hypercholesterolemic diet and E₂ suppresses growth of rats, inducing the secretion of hormones that increase with stress.

Effects of Hydrophilic and Lipophilic β-Sitosterol Derivatives on Cholesterol Absorption and Plasma Cholesterol Levels in Rats

The effects of two phytosterol derivatives of beta-sitosterol, a lipophilic derivative (LPSS) and a hydrophilic derivative (HPSS), on cholesterol uptake and blood lipoprotein levels in rats were compared with those of beta-sitosterol. LPSS and HPSS have solubilities of up to 0.05 g/mL in edible oil and 0.15 g/mL in water at 25 degrees C, respectively. The intragastric administration of either 30 or 50 mg of phytosterols with 10 mg of [4- (14)C]-cholesterol per kg of body weight once a day for 3 consecutive days reduced cholesterol uptake by approximately 30% compared to controls that received cholesterol alone. Feeding a cholesterol-enriched diet containing 1% or 3% beta-sitosterol, LPSS, or HPSS for 2 and 4 weeks resulted in lowered levels of total blood cholesterol and reduced the atherogenic index in all groups. These results indicate that LPSS and HPSS have comparable effects to beta-sitosterol in lowering blood cholesterol levels but they differ from beta-sitosterol in having a solubility advantage.

Nostoc commune var sphaeroides Kutzing, a blue‐green alga, lowers plasma cholesterol levels by promoting fecal neutral sterol excretion in mice

Intake of Nostoc commune var sphaeroides Kützing (N. Commune) has been shown to lower plasma cholesterol levels in rats, but the mechanisms behind the hypocholesterolemic effect have not been elucidated. To elucidate the mechanisms underlying the cholesterol‐lowering effect of N. commune, male C57BL/6 mice were fed the AIN93‐M diet with or without 5% whole N. Commune (wt/wt) supplementation for 4 weeks. N. commune supplementation significantly reduced total plasma cholesterol concentration by ~30 percent compared to controls (P = 0.0049). Hepatic lipids in N. commune fed mice were not significantly altered. However, quantitative Realtime PCR analysis revealed the expression of genes encoding cholesterol 7α‐hydroxylase, sterol regulatory element binding protein 2, and 3‐hydroxy‐3‐methylglutaryl coenzyme A reductase was significantly decreased in mice fed N. commune (P &lt; 0.030). Fecal neutral sterol output, measured by gas chromatography, increased 2‐fold in N. commune‐fed mice, while acidic sterol output remained unchanged. In addition, N. commune supplementation drastically altered mouse intestinal flora populations, demonstrated by denaturing gradient gel electrophoresis. In conclusion, N. commune supplementation exerted a hypocholesterolemic effect, largely in part, by promoting fecal neutral sterol excretion and by modifying the microflora of the intestinal environment.

Oxidative stability of salmon and herring roe lipids and their dietary effect on plasma cholesterol levels of rats

The oxidative stability of lipids from salmon roe and herring roe was compared with those of commercial fish oils originated from sardine and tuna. Both fish roe lipids contained high amounts of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Total EPA and DHA was more than 35% of total fatty acids in both roe lipids. On the basis of oxygen consumption, fish roe lipids showed the higher oxidative stability than both fish oils. This tendency in oxidative stabilities was also confirmed by the determination of propanal formation during oxidation. Analyses of lipid compositions suggested that the higher oxidative stabilities of fish roe lipids would be mainly due to the presence of phospholipids in them. Dietary effects of salmon and herring roe lipids were also determined. Little increase in total cholesterol level was observed in plasma lipids in rats fed salmon and herring roe lipids, although cholesterol content in fish roe lipids were 6.3% and 9.7% of total lipids for salmon roe and herring roe.

Tartary Buckwheat Sprout Powder Lowers Plasma Cholesterol Level in Rats

We examined the effects of different types of buckwheat sprouts on the plasma cholesterol concentration, fecal steroid excretion and hepatic mRNA expression related to cholesterol metabolism in rats. Rats were fed a cholesterol-free diet with 5 g of Kitawasesoba common buckwheat sprout powder (KS)/100 g, 5 g of Hokkai T no. 8 tartary buckwheat sprout powder (HS-8)/100 g or 5 g of Hokkai T no. 9 tartary buckwheat sprout powder (HS-9)/100 g of diet for 4 wk. Control rats were fed a diet with alpha-cornstarch instead of sprout powder for 4 wk. There were no significant differences in food intake, body weight, liver weight or cecal contents among the groups. Plasma total cholesterol concentrations in the HS-8 and HS-9 groups were significantly lower than in the control group, whereas there was no significant difference between the KS and control groups. Fecal bile acid excretion and cecal short-chain fatty acid concentrations in the KS, HS-8 and HS-9 groups were significantly greater than in the control group. Furthermore, fecal matter excretion in the KS, HS-8 and HS-9 groups tended to be increased compared to the control group, with that in the HS-8 group being significantly higher than in the control group. Hepatic cholesterol 7alpha-hydroxylase mRNA expression in the KS, HS-8 and HS-9 groups and hepatic HMG-CoA reductase mRNA expression in the HS-9 group were significantly higher than in the control group. The results suggest that tartary buckwheat sprout powder has a serum cholesterol-lowering function by enhancing fecal bile acid excretion through increased fecal matter excretion or the upregulation of hepatic cholesterol 7alpha-hydroxylase mRNA expression in rats.

Opposing actions of angiotensin II type 1 and 2 receptors on plasma cholesterol levels in rats

There have been very few studies to examine how angiotensin II (AII) affects lipid metabolism. We examined the roles of AII type 1 and type 2 receptors (AT1R and AT2R) in cholesterol metabolism in rats fed either normal chow or high-fructose diets. AII (100 ng/kg per min) or vehicle (saline) was continuously infused through an osmotic mini-pump to normal chow-fed or 60% fructose-fed rats for 2 weeks. AII infusion markedly elevated both the systolic and diastolic blood pressure in the two animal groups. AII did not affect the plasma total cholesterol (TC) in the chow-fed rats. In the AII-infused rats treated with olmesartan medoxomil, an AT1R blocker, we were interested to observe significant decreases in plasma TC and non-high-density lipoprotein (HDL)-cholesterol (C) (TC minus HDL-C), and liver cholesterol content were also decreased. Simultaneous infusion of AII and PD123319, an AT2R blocker, markedly increased non-HDL-C and hepatic cholesterol. The infusion of CGP42112A, an AT2R agonist, decreased non-HDL-C by 30% in normal rats. The AII infusion led to significant elevations in TC and non-HDL-C in the fructose-fed rats, and olmesartan treatment completely rectified this AII-induced hypercholesterolemia. These results suggest that the AII receptors exert opposing effects on the plasma cholesterol level; that is, AT1R increases plasma cholesterol while AT2R decreases it. Fructose feeding may selectively augment the action of AT1R and thereby enhance the increase in plasma cholesterol levels in response to AII infusion.

Goat Milk Feeding Causes an Increase in Biliary Secretion of Cholesterol and a Decrease in Plasma Cholesterol Levels in Rats

The hypocholesterolemic effect of goat milk with respect to cow milk observed in a previous study led us to examine the influence of goat and cow milk in the diet on certain aspects of biliary physiology in normal rats. The fat content in all diets was 10% but the lipid quality was varied: the standard diet was based on virgin olive oil, and the other 2 diets included fat obtained from lyophilized cow milk and goat milk. We characterized the bile secretion, including biliary phospholipid, cholesterol, and bile acid outputs, the interrelation between bile acids and bile lipids, and the lithogenic index. The consumption of goat milk in the diet, compared with that of cow milk, caused an increase in the biliary secretion of cholesterol together with a decrease in plasma cholesterol concentration, whereas values for bile phospholipids, biliary acid concentrations, and the lithogenic index remained normal. Moreover, consumption of this type of milk decreased plasma triglyceride concentration and therefore had a positive effect, similar to that of olive oil (standard diet), on the lipid metabolism; hence, it may be recommended for consumption by the general population.

４種のイモ類デンプンがラットの血しょうコレステロールレベルに及ぼす影響

４種のイモ類デンプンがラットの血しょうコレステロールレベルに及ぼす影響

The effect of taurine on plasma cholesterol concentration in genetic type 2 diabetic GK rats.

The purpose of this study is to investigate the effect of taurine on the plasma cholesterol concentration in genetic type 2 diabetic rats fed cholesterol-free or high-cholesterol diets. Diabetic rats (GK male rats) and normal rats (Wistar male rats) were fed either a cholesterol-free or cholesterol-enriched (1% cholesterol + 0.25% sodium cholate) diet supplemented with or without 3% taurine for 21 or 14 d. Compared to the normal rats, diabetic rats showed a high glucose concentration in their blood and plasma, but it was not affected by taurine feeding. The plasma insulin concentration was higher in the diabetic rats than in the normal rats. At the start of the experiment, the plasma cholesterol concentration was significantly higher in the diabetic rats than in the normal rats. Taurine did not affect the plasma cholesterol level in rats fed the cholesterol-free diet. However, taurine feeding significantly increased the plasma HDL-cholesterol concentration in the diabetic rats fed the cholesterol-free diet. In both the diabetic and normal rats fed the cholesterol diet, the plasma cholesterol concentration was significantly lower in rats fed the diet supplemented with taurine than in the rats fed the control diet. It was concluded that taurine has a hypocholesterolemic effect in both diabetic and normal rats fed diets containing cholesterol. Moreover, these results suggest that taurine seems to affect the HDL-cholesterol metabolism in diabetic rats fed a cholesterol-free diet.

Hypocholesterolemic effect of hesperetin mediated by inhibition of 3-hydroxy-3-methylgultaryl coenzyme a reductase and acyl coenzyme a: Cholesterol acyltransferase in rats fed high-cholesterol diet

HMG-CoA reductase and ACAT are associated with regulation of cholesterol metabolism. In present study, the deglycosylated form of hesperidin, hesperetin, was tested both in vivo and in vitro to examine potential differences in mechanism through which hesperetin might affect cholesterol metabolism. When tested in vitro, hesperetin had no inhibitory effect on either HMG-CoA reductase or ACAT. Male rats were fed a high-cholesterol (1%, w w ) diet with or without hesperetin for 42 d to determine hesperetin effects on plasma lipid levels and hepatic cholesterol metabolism. Hesperetin did not change the levels of hepatic lipids, but decreased the concentration of plasma cholesterol (3.24 mmol/L vs. 3.80 mmol/L). Plasma triglyceride level was not different between control and hesperetin-supplemented group (1.12 mol/L vs. 1.29 mmol/L). HMG-CoA reductase and ACAT activities in the liver were significantly reduced by hesperetin supplementation (2005.0 pmole·min −1·mg proteim −1 vs. 2487.2 pmole·min −1·mg protein −1 for HMG-CoA reductase, 616.4 pmole·min −1·mg protein −1 vs. 806.2 pmoles/min per mg for ACAT). The most noticeble change by the hesperetin supplementation was a marked decrease in daily excretion of fecal neutral sterols (178.7 mg/d vs. 521.9 mg/d). Results indicate that hesperetin decreased the plasma cholesterol level in rats fed a high-cholesterol diet.

Steroid saponins from fenugreek seeds: Extraction, purification, and pharmacological investigation on feeding behavior and plasma cholesterol

The seeds of fenugreek ( Trigonella foenum graecum L.) are traditionally assumed to have restorative properties. We have recently shown that a fenugreek seed extract containing steroid saponins increased food consumption and induced hypocholesterolemia in rats. This study aims to investigate the specific role of purified steroid saponins in these properties. For this purpose, an original technique for extraction and purification of steroid saponins was carried out. Thereafter, the effects of these steroid saponins were investigated on feeding behavior and metabolic endocrine changes in normal and diabetic rats. All the steroid saponins (furostanol type) were extracted from the seeds and separated from all other constituents of the entire extract by using several purification procedures to give an extract containing at least 90% of steroid saponins. Pharmacological experiments were performed in vivo in normal and streptozotocin diabetic rats: steroid saponins were administered chronically mixed with food (12.5 mg/day per 300 g body weight). Our data show that the treatment with steroid saponins significantly increased food intake and the motivation to eat in normal rats, while modifying the circadian rhythm of feeding behavior; it also stabilized the food consumption in diabetic rats, which resulted in a progressive weight gain in these animals, in contrast to untreated diabetic controls. Both in normal and diabetic rats, steroid saponins decreased total plasma cholesterol without any change in triglycerides. In conclusion, the present work reports a clear methodology to obtain all the steroid saponins and demonstrates that these saponins enhance food consumption and motivation to eat, and reduce plasma cholesterol levels in rats.

The effect of leaf protein concentrate from red clover on plasma cholesterol level in rats

AbstractThe effect of native and defatted leaf protein concentrate (LPC) from red clover on plasma cholesterol level in rats was studied. Fat‐free casein was used as a control protein. The native LPC contained 212 g kg−1 of ether extract and oleic acid (C18: 1) was its main fatty acid. LPC protein was relatively poor in sulphur‐containing amino acids. Each protein studied was given to rats with or without soya bean oil. It was found that total cholesterol level in plasma of rats fed with the oil‐containing diets was higher than that of rats fed with the oil‐free diets. Original fat present in the native LPC though rich in unsaturated fatty acids had no hypocholesterolaemic effect. LPC was hypocholesterolaemic compared with casein in diets not containing added soya bean oil, although the difference did not reach statistical significance.

TMP-153, a novel ACAT inhibitor, inhibits cholesterol absorption and lowers plasma cholesterol in rats and hamsters

Effects of TMP-153, N-[4-(2-chlorophenyl)-6,7-dimethyl-3-quinolyl]- N′-(2,4-difluorophenyl)urea, on intestinal and hepatic acyl-CoA:cholesterol acyltransferase (ACAT) activities, cholesterol absorption and plasma cholesterol level in rats and hamsters were studied. TMP-153 has IC 50 values of around 5–10 nM for the hepatic and intestinal ACAT from various animals. The most potent inhibition was observed in the intestinal ACAT from Golden hamsters (IC 50 = 2.3 nM). The inhibition mode of TMP-153 was non-competitive for rat intestinal ACAT. TMP-153 inhibited cholesterol esterification both in human colonic adenocarcinoma cells, LS180, and in human hepatoma cells, HepG2 (IC 50= 150 nM and 330 nM, respectively). [ 14C]cholesterol and cold cholesterol absorption from the small intestine was markedly inhibited by oral administration of TMP-153 (1 mg/kg) without affecting lymph flow and triglyceride absorption. When the compound was given as a dietary admixture, plasma cholesterol was reduced in rats fed a cholesterol diet (ED 50 = 0.25 mg/kg/day), but not in those fed a stock diet. On the other hand, TMP-153 showed more prominent hypocholesterolemic effect in Golden hamsters fed the stock diet (ED 50 = 0.81 mg/kg/day) than in those fed the cholesterol diet (ED 50 = 8.01 mg/kg/day). In hamsters fed the stock diet, TMP-153 markedly decreased the hepatic unesterified cholesterol in addition to esterified cholesterol content, but did not affect bile flow and the biliary secretion of bile acid and lipids. Different mechanisms for plasma cholesterol lowering by TMP-153 between rats and hamsters was discussed.

Effects of Corn Oil and Pectin on the Production of Short-chain Fatty Acids in the Cecum, on the Growth of Colonic Bacteria, and on the Liver Cholesterol Level in Rats.

We examined the effect of pectin and lard on the production of short-chain fatty acids in the cecum, on the the growth of colonic bacteria, and on the liver and plasma cholesterol levels in rats. Added lard (12% w/w) in the diet lowered the production of acetic, propionic and butyric acids in the cecum, and decreased the mass of colonic bacteria. The addition of pectin (3%, w/w) to the diet with lard did not reduce the effect of the lard. The cholesterol level in the liver was significantly increased by the addition of 12% (w/w) of lard to the diet. Feeding with pectin did not lower the cholesterol level in the liver, which was correlated negatively with the concentrations of acetic and propionic acids in the cecum. When cholesterol was added to this diet, the liver and plasma cholesterol levels were increased by additing 12% (w/w) of lard to the diet.

Comparison of Different Types of Dietary Oleic Acid on the Reduction of Plasma Cholesterol Levels in Rats.

Comparison of Different Types of Dietary Oleic Acid on the Reduction of Plasma Cholesterol Levels in Rats.