Cholesterol Levels In Rats Research Articles

High Molecular Weight Poly-Gamma-Glutamic Acid Regulates Lipid Metabolism in Rats Fed a High-Fat Diet and Humans

We investigated the effect of high molecular weight polygamma- glutamic acid (hm gamma-PGA) on adiposity and lipid metabolism of rats in the presence of an obesity-inducing diet. Thirty-two Sprague-Dawley rats were fed either a normal-fat (11.4% kcal fat, NFC) or high-fat (51% kcal fat, HFC) diet. After 5 weeks, half of each diet-fed group was treated with hm gamma-PGA (NFP or HFP) for 4 weeks. The HFC group had significantly higher body weight, visceral fat mass, fasting serum levels of total cholesterol, LDL cholesterol, and leptin, and lower serum HDL cholesterol level compared with those of the NFC group (p < 0.05). Treatment with hm gamma-PGA decreased body weight gain and perirenal fat mass (p<0.05), fasting serum total cholesterol, and mRNA expression of glucose-6- phosphate dehydrogenase (G6PD), regardless of dietary fat contents (p < 0.01). However, hm gamma-PGA increased serum HDL cholesterol in the HFC group (p < 0.05). In vitro, 3-hydroxy-3-methylglutaryl coenzyme-A (HMGCoA) reductase activity was suppressed by the addition of hm gamma-PGA. In agreement with observations in animal study, the supplementation of hm gamma-PGA (150 mg/day) to 20 female subjects in an 8-week double-blind, placebocontrolled study resulted in a tendency to decrease total cholesterol and LDL cholesterol concentrations. We thus conclude that dietary supplementation of hm gamma-PGA may act as a hypocholestrolemic agent, secondary to its inhibitor effect on HMG-CoA reductase, and decrease abdominal adiposity by decreasing hepatic lipogenesis. The present study is an important first step in establishing the effect of hm gamma-PGA on cholesterol levels in rats and humans.

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.

Simultaneous determination of serum lathosterol and cholesterol by semi-micro high-performance liquid chromatography with electrochemical detection

A simple method has been developed for the simultaneous determination of lathosterol and cholesterol by high-performance liquid chromatography with electrochemical detection (HPLC–ECD). Lathosterol was found to be electrochemically oxidized and its current peak height was linearly related to the amount of lathosterol injected, ranging from 0.15 μmol/L to 300 μmol/L ( r = 0.995). Similar results were obtained with cholesterol from 15 μmol/L to 600 μmol/L ( r = 0.995). The separation was carried out with an ODS column, acetonitrile containing 30 mmol/L lithium perchlorate as a mobile phase, and an applied potential at +2.8 V vs. Ag/AgCl. The detection limit ( S/ N = 3) of lathosterol as well as cholesterol was 0.03 μmol/L (0.15 pmol). Total lathosterol in control human and rat serum was determined by the present method with a recovery of more than 95.8% and an RSD ( n = 5) of less than 7.3%. The present method was applied to an experiment with rats to examine the effect of lathosterol feeding. There were no significant changes in serum lathosterol or cholesterol levels in rats fed with a high-lathosterol diet for six days. Therefore, we found this method to be both simple and useful for the simultaneous determination of lathosterol and cholesterol in serum.

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

The ethanol-soluble part of a hot-water extract from Artemisia iwayomogi inhibits liver fibrosis induced by carbon tetrachloride in rats.

This study was carried out to investigate the protective effects of the hot-water extract from Artemisia iwayomogi (Compositae) on carbon tetrachloride-induced liver fibrosis in rats. Liver injury was induced by oral administration of carbon tetrachloride (1 mL kg(-1)) twice a week during 4 weeks of A. iwayomogi treatment. Extracts from A. iwayomogi were prepared and administered to rats orally (2 g kg(-1) as A. iwayomogi for 4 weeks) as follows: group 1, hot-water extract; group 2, ethanol-soluble part of hot-water extract; group 3, ethanol-insoluble part of hot-water extract; and group 4, methanol extract. In rats treated with the ethanol-soluble part of the hot-water extract, liver hydroxyproline content was reduced to 74% that of carbon tetrachloride control rats (P < 0.05). Protein expression of alpha smooth muscle cell like actin was also decreased in rats treated with the ethanol-soluble part of the hot-water extract, which indicates inhibition of hepatic stellate cell activation. Liver malondialdehyde levels were significantly lowered in rats treated with the ethanol-soluble part of hot-water extract (P < 0.05). Serum cholesterol levels in rats treated with hot-water extract, ethanol-soluble or -insoluble parts of hot-water extract or methanol extract were significantly reduced when compared with those of carbon tetrachloride control rats (P < 0.05). The ethanol-soluble part of the hot-water extract from A. iwayomogi inhibited fibrosis and lipid peroxidation in rats with liver fibrosis induced by carbon tetrachloride. Both hot-water extract (either ethanol-soluble or -insoluble) and methanol extract of A. iwayomogi also lowered serum cholesterol levels in fibrotic rats.

Effect of Xylooligosaccharide Enriched Yogurt on Serum Profile in Albino Rats

2 Abstract: The effect of Xylooligosacc haride (XO) enriched yogurt in addition to basal diet on seru m biochemical profile of albino rats assigned to 5 dietary treatments for a period of 21 days were studied. In all groups of rats (n = 5) serum glucose, cholesterol and triglycerides were observed. The weight gain in rats receiving yogurt was higher than those in control group. XO enriched yogurt showed significant improvement in minerals absorption. There was no significant change in serum cholesterol level of rats fed on yogurt with or without XO en richment but a fair reduction in serum glucose content was noted. XO as a functiona l ingredient can be incorporated in formulating dairy products with improved health benefits like lowering glucose levels.

Potato and soy peptides alter caecal fermentation and reduce serum non‐HDL cholesterol in rats fed cholesterol

AbstractWe examined the effect of potato peptides (PPC) in rats fed a cholesterol‐enriched diet, in comparison with two cholesterol‐enriched diets containing soy peptides (SPC) or casein (CNC), and a cholesterol‐free diet containing casein (CN) for 4 weeks. The serum non‐high‐density lipoprotein (HDL) cholesterol level was lower in the PPC‐ (–18.39%) and SPC‐fed (–32.76%) groups (p &lt;0.05) than in the CNC‐fed group at the end of the feeding period. The low‐density lipoprotein receptor mRNA level in the PPC‐fed group, and cholesterol 7α‐hydroxylase and scavenger receptor class B type 1 mRNA levels in the SPC‐fed group, were higher (p &lt;0.05) than in the CN‐ and CNC‐fed groups. Faecal neutral sterol and caecal short‐chain fatty acid concentrations in the PPC‐ and SPC‐fed groups were higher (p &lt;0.05) than in the CN‐ and CNC‐fed groups. The faecal total acidic sterol concentration was higher in the SPC‐fed group than in the CN‐ and PPC‐fed groups. Caecal anaerobe and Bifidobacterium populations were higher (p &lt;0.05) in the PPC‐ and SPC‐fed groups than in the CN‐fed group. This study suggests that potato peptides, as soy peptides, alter caecal fermentation and steroid absorption and reduce the serum non‐HDL cholesterol level in rats fed cholesterol.

Quantitative Analysis of Saponins in a Tea-Leaf Extract and Their Antihypercholesterolemic Activity

A novel simple method using liquid chromatography/time-of-flight mass spectrometry (LC/TOF-MS) and LC/UV was established for the quantification of saponins in an extract from green tea leaves. The amount of saponins in a fraction with high in vitro antihypercholesterolemic activity, Fr2-3, was determined to be 72%. An in vivo experiment showed that the addition of 0.5% Fr2-3 to a high-cholesterol diet suppressed the increase in serum cholesterol levels in rats. Fr2-3 induced a decrease in the liver cholesterol and triglyceride levels and an increase in the fecal excretion of cholesterol. These results indicate tea-leaf saponins to be the active components in Fr2-3 and that these saponins exhibited antihypercholesterolemic activity by inhibiting cholesterol absorption in the intestines.

Aquilegia vulgaris extract attenuates carbon tetrachloride-induced liver fibrosis in rats

Six groups of male Wistar rats were treated as follows: in groups II, III and V liver damage was induced by CCl 4 ( per os, 1590 mg/kg b.w. day) given 2 days a week for 6 weeks; group III was treated simultaneously with ethanol extract of A quilegia vulgaris (100 mg/kg b.w. day) for 6 weeks; group V with silymarin, positive control, at a dose of 100mg/kg b.w. day for 6 weeks; and groups IV and VI received only the extract or silymarin, respectively. Microsomal lipid peroxidation in the liver increased following CCl 4 treatment by 61–213% and was not changed significantly by the extract. The effect of silymarin was more pronounced, 19–52% decrease in the lipid peroxidation level. Hepatic glutathione was depleted by 22% in CCl 4-treated rats. The extract tested did not change this parameter. The activity of antioxidant enzymes was significantly reduced after CCl 4 administration, by 42–63%. Co-administration of the extract or silymarin resulted in significant increase in these enzymes activity; however, the basal level was not reached. Hepatic hydroxyproline concentration was elevated over 5-fold in comparison with controls. Co-administration of the extract or silymarin decreased the level of hydroxyproline by 66% and 55%, respectively. Activity of serum hepatic enzymes was elevated in rats treated with CCl 4 by 47–8700%. Both the extract and silymarin reduced significantly these enzymes’ activity. The extract caused a fall in bilirubin and cholesterol level in rats treated with CCl 4 by 42% and 17%, respectively. Histopathological examination revealed less-severe fibrosis in rats co-administered the extract or silymarin when compared to animals treated with CCl 4 alone.

Lowering serum cholesterol level by feeding a 40% ethanol-eluted fraction from HP-20 resin treated with hot water extract of adzuki beans ( Vigna angularis) to rats fed a high-fat cholesterol diet

Objective Hot water extract of adzuki beans ( Vigna angularis) was subjected to HP-20 resin chromatography. The fraction eluted from the column using 40% ethanol (EtEx.40) was investigated by its effect on serum lipids in rats fed a high-fat cholesterol and/or cholesterol-free high-fat diet. Methods The rats were divided into 4 groups. Groups 1 and 2 were fed a high-fat cholesterol diet with or without 3.5% EtEx.40 for 2 wk. Group 3s and 4 were fed a high-fat cholesterol-free diet with or without 3.5% EtEx.40 for 2 wk. Results In the high-fat-cholesterol diet groups, there was no significant difference in food intake in the experimental diet group when compared with the control group. Serum total cholesterol level was significantly decreased in the rats fed the EtEx.40 diet, but there was no difference in fecal excretion of cholesterol and bile acid between the two dietary groups. Conversely, in the high-fat cholesterol-free diet groups, ingestion of EtEx.40 reduced serum triacylglycerol concentration. Conclusion Ingestion of EtEx.40 suppressed serum cholesterol level in rats fed the high-fat cholesterol and serum triacylglycerol level in rats fed the high-fat cholesterol-free diet. These mechanisms did not become clear in this experiment.

매생이 추출물이 흰주의 간장조직과 분변 중의 콜레스테롤 함량에 미치는 영향

We investigated the effect of a green seaweed Capsosiphon fulvescens extract (CFE) on the serum, liver tissue, and fecal cholesterol levels in rats. Male Sprague-Dawley rats (four weeks old) were given on of three diets for four weeks: basal, high cholesterol, and CFE, The total serum and liver tissue cholesterol levels in the CFE group were significantly decreased compared to those in the cholesterol group. The CFE group showed increased amounts of feces, total fecal bile acid and dietary fiber as compared to basal and cholesterol group. Hematoxylin and eosin staining revealed fat droplets in the livers of the rats in the cholesterol group; however, a decreased number of droplets was observed in the rats fed the CFE diet. Our results suggest that CFE supplementation may improve lipid metabolism, by controling serum and liver tissue cholesterol levels, and by increasing the total amounts of bile acid, dietary fiber and cholesterol excretion in feces.

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.

Antihypercholesterolemic effect of Chinese black tea extract in human subjects with borderline hypercholesterolemia

A water-soluble extract of a traditional Chinese black tea (Pu-Ehr) has been shown to precipitate mixed bile salt micelles in foods. In addition, long-term ingestion of this black tea extract (BTE) significantly reduces blood cholesterol levels in rats. We investigated the effects of BTE tablets (a formula designed to enhance compliance) as a dietary supplement in a 3-month double-blind randomized group comparison study in borderline hypercholesterolemic human subjects (n = 47). All subjects ingested BTE tablets (333 mg) or placebo 3 times daily before meals for 3 months. In the BTE-treated group, the initial mean blood total (6.14 +/- 0.14 mol/L) and low-density lipoprotein (LDL) cholesterol (4.32 +/- 0.14 mol/L) levels decreased with time and were significantly (P < .01) lower (total cholesterol, 5.62 +/- 0.11; LDL cholesterol, 3.81 +/- 0.13 mol/L) after 3 months of ingestion. Furthermore, the mean body weights (P < .05) and triacylglycerol levels (P < .01) were also significantly reduced after 3 months of BTE intake compared with the baseline levels. Significant improvements in the mean LDL cholesterol, body weight, and triacylglycerol values were not accompanied with undesirable changes in other biochemical parameters measured in the subjects. None of the subjects complained of any adverse effects (eg, abdominal distension). The results indicate that BTE intake elicited a significant antihypercholesterolemic effect and might be useful for improving blood cholesterol levels in subjects at risk for heart disease or obesity.

Increase of Serum Cholesterol Levels by Heat‐Moisture‐Treated High‐Amylose Cornstarch in Rats Fed a High‐Cholesterol Diet

The effects of four cornstarches containing various contents of resistant starch on serum and liver cholesterol levels in rats fed a high-cholesterol diet were investigated. Male Sprague Dawley rats (aged 4 weeks) were divided into four groups (n = 7) and fed high-cholesterol diets containing 15% of cornstarch (CS), heat-moisture-treated CS (HCS), high-amylose CS (HA), or heat-moisture-treated HA (HHA) for 21 days. The results showed that the serum and hepatic level of total cholesterol, LDL-cholesterol, and triglyceride in rats of the HHA group and their arteriosclerosis index were significantly higher, suggesting that HHA increases the risk of arteriosclerosis under a high-cholesterol dietary condition. No significant between-group differences were noted in the levels of plasma mevalonic acid and hepatic HMG-CoA reductase mRNA, whereas fecal cholesterol excretion was significantly higher in the HHA group, indicating that the elevation of the serum and liver cholesterol levels was not due to the promotion of liver cholesterol synthesis and cholesterol absorption in the intestine.

Potato and Soy Peptide Diets Modulate Lipid Metabolism in Rats

Dietary plant and animal peptides have been shown to reduce serum lipids. However, the potential of food-derived peptides has yet to be fully elucidated. We investigated the physiological importance of potato peptides in rats fed on a cholesterol-free diet containing 20% potato peptides (PP), when compared with two diets containing either 20% casein (CN) or 20% soy peptides (SP). The high-density lipoprotein (HDL)-cholesterol (+13.8%) and serum triglyceride (-38%) concentrations in the PP-fed group, non-HDL-cholesterol level in the PP- (-22.5%) and SP- (-15.7%) fed groups, and serum total cholesterol concentration (-12%) in the SP-fed group, were significantly different from the control group at the end of the experiment. The fecal excretion of neutral and acidic sterols was higher in the PP- and SP-fed groups, respectively, relative to the control group. These results indicate that the observed changes in the serum cholesterol levels in rats fed on soy and potato peptide appear to have been due to different mechanisms.

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.

Dietary Structured Lipids and Phytosteryl Esters: Blood Lipids and Cardiovascular Status in Spontaneously Hypertensive Rats

This study examined the dietary effects of enzymatically modified sesame oil with caprylic acid (structured lipids, SL) and phytosteryl esters (PE) on blood lipid profiles and cardiovascular parameters of spontaneously hypertensive rats (SHR) fed high-fat and high-cholesterol (HFHC) diets. The dietary groups were: normal diet (control), sesame oil (SO), SL, SO fortified with PE (SOP), and SL fortified with PE (SLP). After 9 weeks of feeding, the body weights, liver weights, and liver weight/body weight ratios in all HFHC-fed groups were higher than controls. Plasma total and LDL cholesterol levels in all HFHC-fed groups were similar to one another but higher than those in controls. Plasma HDL cholesterol levels in rats fed SOP and SLP were higher than those in controls or rats fed SO and SL. Plasma HDL/total cholesterol ratios in rats fed SOP and SLP were similar to those in controls and were higher than those in rats fed SO and SL. There was no difference in plasma lipid profiles between rats fed SO and SL. Arterial blood pressures (BP) in conscious HFHC-fed rats were similar to those in controls whereas heart rates (HR) in all HFHC-fed groups were similar to one another but were higher than that in controls. These findings demonstrate that (1) the dietary effects of SL on plasma lipid profiles and resting BP and HR are similar to those of SO, (2) PE had positive effects on plasma lipid profiles, and (3) 9-week intake of SL and PE did not have pronounced effects on resting BP but induced tachycardia in SHR.

Interesterified coconut oil blends with groundnut oil or olive oil exhibit greater hypocholesterolemic effects compared with their respective physical blends in rats

Blended oils consisting of coconut oil (CO) with groundnut oil (GNO) or CO with olive oil (OLO) were prepared to contain balanced amounts of saturated to unsaturated fatty acids. Blended oils were subjected to interesterification reactions catalyzed by IM-60 lipase from Rhizomucor miehei. Weanling rats were fed with native, blend, and interesterified oils at 10% level for 60 days. Serum cholesterol levels were lowered by 6% and 13%, respectively, in rats given blended oils containing CO/GNO and CO/OLO in comparison with rats fed with CO. Serum cholesterol levels were found to be reduced by 27% and 25%, respectively, when these blended oils were subjected to interesterification reactions and fed to rats. Similarly the liver cholesterol levels were decreased by 11% and 21%, respectively, when rats were given CO/GNO blends and interesterified oils compared with those given CO. Cholesterol levels in liver of rats given blend and interesterified oils of CO/OLO were reduced by 3% and 32%, respectively, as compared with that in rats given CO alone. These studies indicated that interesterified oils of CO with GNO or with OLO are more efficient in lowering cholesterol levels in rats compared with physical blends of CO with GNO or OLO. Therefore, although the physical blends had similar fatty acid compositions as that of interesterified oils, the hypocholesterolemic effects of interesterified oils were significantly greater than that which could be obtained from oils prepared by simple blending.