The mechanism of dietary cholesterol effects on lipids metabolism in rats

Voluntary exercise fails to prevent metabolic dysfunction-associated steatotic liver disease progression in male rats fed a high-fat high-cholesterol diet

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a major public health issue with a worldwide prevalence of 30%-32%. In animal models, voluntary exercise may be an alternative to forced physical activity, avoiding stress, potential injuries, and being logistically simpler. Here, we assessed voluntary exercise (Vex) in Sprague-Dawley rats fed a high-fat, high-cholesterol diet for 18 weeks to induce MASLD. We quantified workload (speed and distance) using exercise wheels and evaluated energy expenditure using calorimetric cages. MASLD progression was assessed using circulating and hepatic biochemical and gene markers of steatosis, inflammation, and fibrosis. The animals ran an average of 301 km during the study period, with the average daily distance peaking at 4937 m/day during Weeks 3-4 before decreasing to 757 m/day by the end of the study. Rats exposed to Vex showed no improvement in any of the MASLD-associated features, such as steatosis, inflammation, or fibrosis. Rats exposed to Vex exhibited a higher total energy expenditure during the night phase (+0.35 kcal/h; p = 0.003) without resulting in any effect on body composition. We conclude that, in our experimental conditions, Vex failed to prevent MASLD progression in male Sprague-Dawley rats exposed to a high-fat high-cholesterol diet for 18 weeks.

Molecular Mechanism for Hepatic Glycerolipid Partitioning of n-6/n-3 Fatty Acid Ratio in an Obese Animal Biomodels

The n-6/n-3 metabolic pathway associated with hepatic glycerolipid portioning plays a key role in preventing obesity. In this nutrition metabolism study, we used in vivo monitoring techniques with 40 obese male Sprague-Dawley strain rats attached with jugular-vein cannula after obesity was induced by a high-fat diet to determine the molecular mechanism associated with hepatic glycerolipid partitioning involving the n-6/n-3 metabolic pathway. Rats were randomly assigned to four groups (10 animals per group), including one control group (CON, n-6/n-3 of 71:1) and three treatment groups (n-6/n-3 of 4:1, 15:1 and 30:1). They were fed with experimental diets for 60 days. Incorporation rates of [14C]-labeling lipid into glycerolipid in the liver were 28.87−37.03% in treatment groups fed with diets containing an n-6/n-3 ratio of 4:1, 15:1 and 30:1, which were significantly (p < 0.05) lower than that in the CON (40.01%). However, 14CO2 emission % of absorbed dose showed the opposite trend. It was significantly (p < 0.05) higher in a treatment groups (n-6/n-3 of 4:1, 15:1 and 30:1, 30.35−45.08%) than in CON (27.71%). Regarding the metabolic distribution of glycerolipid to blood from livers, phospholipid/total glycerolipid (%) was significantly (p < 0.05) lower in CON at 11.04% than in treatment groups at 18.15% to 25.15%. Moreover, 14CO2/[14C]-total glycerolipid (%) was significantly (p < 0.05) higher in treatment groups at 44.16−78.50% than in CON at 39.50%. Metabolic distribution of fatty acyl moieties flux for oxidation and glycerolipid synthesis in the liver were significantly (p < 0.05) better in order of 4:1 > 15:1 > 30:1 than in the CON. Our data demonstrate that n-6/n-3 of 4:1 could help prevent obesity by controlling the mechanism of hepatic partitioning through oxidation and esterification of glycerolipid in an obese animal biomodel.

Dietary cholesterol promotes growth and ecdysone signalling pathway by modulating cholesterol transport in swimming crabs (Portunus trituberculatus)

Cholesterol, as an indispensable nutrient, regulates molting and growth in crustacean. As crustaceans are unable to biosynthesize cholesterol de novo, it is central to understand how dietary cholesterol affects molting in crustaceans. An 8-week feeding trial was conducted to evaluate the effects of dietary cholesterol level (0.12%, 0.43%, 0.79%, 1.00%, 1.30% and 2.50%) on growth, cholesterol metabolism and expression of genes related to lipid and ecdysone metabolism in female swimming crabs (Portunus trituberculatus). A total of 192 crabs (1.41 ± 0.05 g) were randomly distributed into 192 aquaria. Each treatment had 4 replicates with each replicate containing 8 crabs. Crabs fed the 1.00% cholesterol diet showed best growth performance, and thus based on percent weight gain, the optimal dietary cholesterol requirement was calculated at 1.01%. Tissue cholesterol concentrations were positively correlated with dietary cholesterol level. The contents of functional fatty acids in hepatopancreas significantly increased as dietary cholesterol increased from 0.12% to 2.50% (P < 0.05). The expression levels of genes related to lipogenesis pathway, lipid catabolism and fatty acid oxidation were significantly down-regulated with increased dietary cholesterol level (P < 0.05). The highest expression levels of cholesterol transport genes, low-density lipoprotein receptor (ldlr) and low-density lipoprotein receptor-related protein 2 (lrp2) occurred in crabs fed the 1.30% cholesterol diet. Moreover, hormones related to molting such as crustacean hyperglycemic hormone (CHH), methyl farnesoate (MF), molt-inhibiting hormone (MIH), and ecdysone in hemolymph were significantly influenced by dietary cholesterol level (P < 0.05). The highest expression levels of ecdysone receptor (ecr) and chitinase 1 (chi1) in eyestalk and hepatopancreas were found in crabs fed the diet containing 1.00% cholesterol (P < 0.05). In conclusion, the optimal dietary level was beneficial to functional fatty acid accumulation, regulated lipid metabolism, promoted the ecdysone signalling pathway by improving the cholesterol transport, and improved the molting rate and growth of swimming crabs.

Sex-specific endothelial dysfunction induced by high-cholesterol diet in rats: The role of protein tyrosine kinase and nitric oxide

BACKGROUND AND AIMS

Atherosclerosis is a chronic process playing a crucial role in the pathogenesis of cardiovascular disease. Sex-specific differences in the incidence of atherosclerosis indicate that estrogen has a protective effect on the cardiovascular disease. However, the role of sex on endothelium responses in animal models of high cholesterol (HC) diet-induced atherosclerosis has not been fully investigated. This study was aimed to investigate vascular responses in HC-fed rats.

METHODS AND RESULTS

Male and female Sprague rats (12-week-old) were treated with either a standard diet (n = 12 of each sex) or an HC enriched diet (n = 12 of each sex) containing 2% cholesterol for 24 weeks. HC treated animals (both sexes) showed increased levels of total cholesterol, LDL-cholesterol, triglyceride and blood pressure (BP) compared to control rats. While the BP of control rats (both sexes) was increased following aminoguanidine administration (AG, 100 mg/kg i.p.), it was not changed in HC animals (both sexes). The hypotensive effect of acetylcholine was significantly impaired in male HC-treated rats. In vitro experiments demonstrated that aortic rings from HC group (both sexes) had an increased contractile response to phenylephrine and a decreased vasodilatory response to acetylcholine. The vasorelaxant effect of acetylcholine in HC rats (only male) was improved by applying 10^-5 M genistein (tyrosine kinase inhibitor) or AG.

CONCLUSION

HC diet alters endothelium function through Nitric oxide (NO) and tyrosine kinase pathways in male rats.

L-Carnitine effect on induced hyperlipidemia on premature rats: fertility profile

This study was designed to investigate the effect of hypercholesterolemia on the reproductive performance of premature male rats and to evaluate the influence of L-Carnitine (CAR) in maintaining their fertility. Sixty rats were divided randomly into three groups. Control group (CG n=20 rats), cholesterol feeding group 1 (CFG1 n=20 rats) fed 1.5% cholesterol with diet for one month, and cholesterol feeding group 2 (CFG2 n=20 rats) fed 1.5% cholesterol with diet + CAR 150 mg/kg body weight (B.W.) given by water for one month. Results showed a significant increase in body weight of CFG1 compared with CG and CFG2. The lipid profile of CFG1 after one month of feeding cholesterol showed a significant increase in serum cholesterol and triglyceride compared with CG and with the group that watered by CAR and CFG2. Results of sperms parameters in CGF2 showed a significant increase in sperms count with sperms live percentage and a significant decrease in sperms abnormalities percentage compared with CGF1 and CG. The hormonal profile showed a significant decrease in serum testosterone levels in rats from CFG1 compared with CFG2 and CG. In conclusion, CAR is a powerful antioxidant that can maintain the parameters of sperms of hypercholesterolemic premature rats, which may enhance the fertilizing ability of subfertile rats that may occur due to hyperlipidemia.

Comparison of the Cholesterol-Lowering Effect of Scallop Oil Prepared from the Internal Organs of the Japanese Giant Scallop (Patinopecten yessoensis), Fish Oil, and Krill Oil in Obese Type II Diabetic KK-A y Mice

Due to the growing demand of n-3 polyunsaturated fatty acids (PUFA) as supplements and pharmaceutical products worldwide, there are concerns about the exhaustion of n-3 PUFA supply sources. We have successfully prepared high-quality scallop oil (SCO), containing high eicosapentaenoic acid and phospholipids contents, from the internal organs of the Japanese giant scallop (Patinopecten yessoensis), which is the largest unutilized marine resource in Japan. This study compared the cholesterol-lowering effect of SCO with fish oil (menhaden oil, MO) and krill oil (KO) in obese type II diabetic KK-A ^y mice. Four-week-old male KK-A ^y mice were divided into four groups; the control group was fed the AIN93G-modified high-fat (3 wt% soybean oil + 17 wt% lard) diet, and the other three groups (SCO, MO, and KO groups) were fed a high-fat diet, in which 7 wt% of the lard in the control diet was replaced with SCO, MO, or KO, respectively. After the mice were fed the experimental diet for 42 days, their serum, liver, and fecal lipid contents as well as their liver mRNA expression levels were evaluated. The SCO group had significantly decreased cholesterol levels in the serum and liver; this decrease was not observed in the MO and KO groups. The cholesterol-lowering effect of SCO was partly mediated by the enhancement of fecal total sterol excretion and expression of liver cholesterol 7α-hydroxylase, a rate-limiting enzyme for bile acid synthesis. These results indicate that dietary SCO exhibits serum and liver cholesterol-lowering effects that are not found in dietary MO and KO and can help prevent lifestyle-related diseases.

Sub-acute oral toxicity study of aqueous extract of tobacco leaves (Nicotiana tabacum L.) on lipid profile, the tissue, and serum of the liver and kidney of male Wistar rats

CONTEXT

Tobacco consumption may pose a very serious threat to the physiological state of the body; yet, fewer records have been documented in that regard.

OBJECTIVE

We investigated the impact of aqueous extract of tobacco leaves on the lipid profile, the tissue, and serum levels of the liver and kidney of male Wister rats.

MATERIALS AND METHODS

Rats (n = 52; weight = 33 - 47 g; ∼ 2½ weeks old) were acclimatised for 7 days and administered aqueous extract of tobacco leaves at 100, 200, 400, 0 mg/kg of body weight (to group A, B, C, D) for 30 days.

RESULTS

Compared with the control group, the kidney tissue and serum (i.e., urea and creatinine) were not influenced, in contrast, indices of the liver such as AST, ALT, and ALP, dose-dependently increased. Changes such as coagulative necrosis resulted in the infiltration of mononuclear inflammatory cells and the vacuolar degeneration of the liver. Beside the reduction in the high-density lipoprotein of the rats, there was an increase in the concentration of triglycerides, very low-density lipoprotein, low-density lipoprotein, and the total cholesterol.

CONCLUSION

Thus, extract of tobacco leaves can greatly influence the body lipid profile, beside the serum and tissues of the liver.

Antiobesity efficacy of asiatic acid: down-regulation of adipogenic and inflammatory processes in high fat diet induced obese rats

In the current study, we evaluated the effects of Asiatic acid (AA) on lipid metabolic markers in HFD-induced obese Sprague-Dawley rat model. AA (20 mg/kg BW) was administered orally to HFD-fed rats for 42 days. Changes in body composition, glucose, insulin resistance (IR) and lipid profiles of tissues, plasma and the pattern of gene expression of peroxisome proliferator-activated receptor-γ (PPAR-γ) and its target genes fatty-acid synthase (FAS), adipocyte protein-2 (aP2) and uncoupling protein-2 (UCP-2) and pro-inflammatory factor tumor necrosis factor (TNF)-α were observed in experimental rats. Oral administration of AA exerts therapeutic effects similar to orlistat in attenuating body weight gain, glucose, IR, plasma and tissue lipids and mRNA levels of PPAR-γ, FAS, aP2 and inflammatory factor TNF-α and increasing UCP-2 expression in HFD-fed rats. Hence, these findings concluded that AA attenuate HFD-induced obesity by modulating PPAR-γ and its target genes and regulate lipid metabolism, suggesting their possible antiobesity effects.

Icariin enhances AMP-activated protein kinase and prevents high fructose and high salt-induced metabolic syndrome in rats

Metabolic syndrome (MetS) is an increasing health threat and often leads to cardiovascular complications. The aim of this study was to evaluate icariin’s ability to combat MetS induced in rats and outline the involved mechanisms of action. Rats were grouped in four batches. The controls received a regular diet and water. MetS was induced in the remaining three groups using a high-salt high-fructose diet. Groups 1 and 2 were given daily doses of saline, while Groups 3 and 4 received 25 and 50 mg/kg icariin, respectively, for 12 weeks in total. The experimental protocol was carried out for 12 weeks consecutively. Icariin significantly decreased body mass index (BMI), adiposity index and body weight. Further, icariin protected against dyslipidemia, hyperglycemia, and hyperinsulinemia and improved insulin resistance as given by the homeostatic model assessment of insulin resistance (HOMA-IR) values. Icariin guarded against the rise in serum interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α). In addition, it significantly inhibited the decrease in mRNA expression of glucose transporter type 4 (GLUT4) and liver kinase B1 (LKB1). These effects were accompanied by decreased liver content of nuclear factor kappa B (NFκB) and enhanced serum levels of phosphorylated 5ʹ-adenosine monophosphate-activated protein kinase (p-AMPK). Further, icariin significantly increased p-AMPK/AMPK ratio in liver tissues. Conclusively, icariin offers protection in experimentally induced MetS, partially due to AMPK activation.

In vitro and in vivo studies of nanoparticles of chitosan-Pandanus tectorius fruit extract as new alternative treatment for hypercholesterolemia via Scavenger Receptor Class B type 1 pathway

Pandanus tectorius fruit, a natural product rich in tangeretin and ethyl caffeate, has been reported to have potential as anti-hypercholesterolemia agent via Scavenger Receptor Class B type 1 (SR-B1) pathway. However, due to its semi-polar properties, P. tectorius extract exhibits poor solubility when used as a medical remedy. The extract’s solubility can potentially be improved through a synthesis of nanoparticles of chitosan-P. tectorius fruit extract. This can also increase the extract’s SR-B1 gene expression activity. To date, no studies of nanoparticles of chitosan-P. tectorius fruit extract and its pathway via SR-B1 have been published anywhere. In this study, cytotoxicity properties against HepG2 were explored by MTT. Then luciferase assay was used to detect their effectiveness in increasing SR-B1 activity. An in vivo study using Sprague dawley was carried out to observe the extract nanoparticles’ effectiveness in reducing the cholesterol levels and the toxicity property in rat’s liver. As the results showed, the extract nanoparticles had no cytotoxic activity against HepG2 cells and exhibited higher SR-B1 gene expression activity than the non-nanoparticle form. As the in vivo study proved, nanoparticle treatment can reduce the levels of TC (197%), LDL (360%), and TG (109%), as well as increase the level of HDL cholesterol by 150%, in comparison to those for the untreated high-cholesterol diet group. From the toxicity study, it was found that there was non-toxicity in the liver. It can be concluded that nanoparticles of chitosan-P. tectorius fruit extract successfully increased P. tectorius fruit extract’s effectiveness in reducing hypercholesterolemia via SR-B1 pathway. Hence, it can be suggested that nanoparticles of chitosan-P. tectorius fruit extract is safe and suitable as an alternative treatment for controlling hypercholesterolemia via SR-B1 pathway.

Lactobacillus reuteri attenuates cardiac injury without lowering cholesterol in low-density lipoprotein receptor-deficient mice fed standard chow

Disruption of the normal gut microbiome (dysbiosis) is implicated in the progression and severity of myriad disorders, including hypercholesterolemia and cardiovascular disease. Probiotics attenuate and reverse gut dysbiosis to improve cardiovascular risk factors like hypertension and hypercholesterolemia. Lactobacillus reuteri is a well-studied lactic acid-producing probiotic with known cholesterol-lowering properties and anti-inflammatory effects. In the present study, we hypothesized that L. reuteri delivered to hypercholesterolemic low-density lipoprotein receptor knockout (LDLr KO) mice will reduce cholesterol levels and minimize cardiac injury from an ischemic insult. L. reuteri [1 × 10⁹ or 50 × 10⁶ colony-forming units (CFU)/day] was administered by oral gavage to wild-type mice and LDLr KO for up to 6 wk followed by an ischemia-reperfusion (I/R) protocol. After 4 wk of gavage, total serum cholesterol in wild-type mice receiving saline was 113.5 ± 5.6 mg/dL compared with 113.3 ± 6.8 and 101.9 ± 7.5 mg/dL in mice receiving 1 × 10⁹ or 50 × 10⁶ CFU/day, respectively. Over the same time frame, administration of L. reuteri at 1 × 10⁹ or 50 × 10⁶ CFU/day did not lower total serum cholesterol (283.0 ± 11.1, 263.3 ± 5.0, and 253.1 ± 7.0 mg/dL; saline, 1 × 10⁹ or 50 × 10⁶ CFU/day, respectively) in LDLr KO mice. Despite no impact on total serum cholesterol, L. reuteri administration significantly attenuated cardiac injury following I/R, as evidenced by smaller infarct sizes compared with controls in both wild-type and LDLr KO groups. In conclusion, daily L. reuteri significantly protected against cardiac injury without lowering cholesterol levels, suggesting anti-inflammatory properties of L. reuteri uncoupled from improvements in serum cholesterol.NEW & NOTEWORTHY We demonstrated that daily delivery of Lactobacillus reuteri to wild-type and hypercholesterolemic lipoprotein receptor knockout mice attenuated cardiac injury following ischemia-reperfusion without lowering total serum cholesterol in the short term. In addition, we validated protection against cardiac injury using histology and immunohistochemistry techniques. L. reuteri offers promise as a probiotic to mitigate ischemic cardiac injury.

Inhibitory effects of tangeretin and trans-ethyl caffeate on the HMG-CoA reductase activity: Potential agents for reducing cholesterol levels

One of the pathways to reduce cholesterol production in the liver is through the inhibition of HMG-Coa reductase (HMGCR) by current drugs, statins. However, these have side effects if consumed in prolonged periods. Tangeretin and trans-ethyl caffeate as alternative drugs in reducing hypercholesterolemia and preventing atherosclerosis have never been reported. Their effects on inhibiting HMGCR activity were investigated through enzymatic method (in vitro and in vivo). The toxicity property was analyzed on the Serum Glutamate Oxalate Transaminase (SGOT)/Serum Glutamate Piruvate Transaminase (SGPT) levels and rat liver histology. The results showed that both compounds inhibited HMGCR activity significantly compare to the control simvastatin (p < 0.05). Tangeretin which showed very good activity in inhibiting HMGCR (83.8 of % inhibition, equal to simvastatin) was selected and used for anti-hypercholesterolemia in vivo assessment. Furthermore, tangeretin was shown to effectively reduced Total Cholesterol (TC) and Low Density Lipoprotein (LDL), and increased High Density Lipoprotein (HDL) levels significantly compared to the simvastatin group (p < 0.05). Tangeretin group was also proven to inhibit HMGCR rat liver activity significantly compare to the control simvastatin (p < 0.05). The toxicity study on the SGOT/SGPT levels and liver histology revealed that there were no side effects after administration by tangeretin. Results found that both tangeretin and trans-ethyl caffeate are potent candidates as anti-hypercholesterolemia agent in vitro. In addition, tangeretin was also shown to be safe and suitable as an alternative treatment for controlling hypercholesterolemia in vivo as well as have potency for preventing atherosclerosis.

In vivo monitoring of hepatic glycolipid distribution of n-6 ∕ n-3 in jugular-vein-cannulated rats as a nutritional research model for monogastric animal

The metabolic distribution via blood from liver of glycerolipids by omega-6 to omega-3 fatty acid (n-6 / n-3) ratio in monogastric animal nutrition is very important. In vivo monitoring technique using jugular-vein-cannulated rats as a nutritional model for monogastric animal can yield important insights into animal nutrition. This study was conducted to determine the effect of different n-6 / n-3 ratios (71:1, 4:1, 15:1, 30:1) on metabolic distribution of glycerolipids newly synthesized and secreted in the liver of the rats and explore the mechanism involved. Regarding 14CO2 released from oxidation of glycerolipid metabolism, it was the highest (22.5 %) in groups with a n-6 / n-3 ratio of 4:1 (P<0.05). The control group showed the highest total glycerolipid level, followed by the 30:1, 15:1, and 4:1 groups in order (P<0.05). When secreted triacylglycerol level of each group was compared with that of the control group, the 4:1, 15:1, and 30:1 groups were decreased by 36.3 %, 20.9 %, and 13.3 %, respectively (P<0.05). Regarding the distribution of phospholipid against total glycerolipid compared to the control group, the 4:1, 15:1, and 30:1 groups were 1.38, 1.29, and 1.17 times higher, respectively (P<0.05). In the comparison of 14CO2 emission against total glycerolipid compared with the control group, the 4:1, 15:1, and 30:1 groups were 1.61, 1.52, and 1.29 times higher, respectively (P<0.05). These results demonstrate that a dietary n-6 / n-3 fatty acid ratio of 4:1 could significantly decrease harmful lipid levels in the blood by controlling the mechanism of metabolic distribution via blood from triglyceride and phospholipid newly synthesized in the liver of cannulated rat.

High-Fat Diets and LXRs Expression in Rat Liver and Hypothalamus

Disturbances on lipid metabolism are associated with health disorders. High-fat diets (HFDs) consumption promotes cardiovascular and neurodegenerative diseases where cholesterol plays an important role. Among regulators of this steroid homeostasis, the liver X receptors (LXRs) induce genes that protect cells from cholesterol overload. We previously described how both hypothalamic LXRα and LXRβ are sensitive to a high-fructose diet, suggesting that these receptors trigger responses related to control of energy and food intake. The present work's main objective was to study the effect of different HFDs on LXRs expression (in hypothalamus and liver), and lipid profile. Male rats received control diet (CD), HFD1 (CD + bovine fat (BF)), HFD2 (CD + BF + cholic acid (CA)), HFD3 (CD + BF + cholesterol), or HFD4 (CD + BF + CA + cholesterol) for different time periods. Hypothalamic LXRβ, both hepatic LXRs subtypes, and total cholesterol (TC) raised after 2 weeks of HFDs. Four and 8 weeks of HFD3 and HFD4 increased the LXRs subtypes in both tissues and TC levels. Only HFD4 reduced triglycerides (TG) levels after 2 and 8 weeks. The TC and TG values correlated significantly with LXRs expression only in rats fed with HFD4. These data add relevant information about how diet composition can produce different scales of hypercholesterolemia states accompanied with central and peripheral changes in the LXRs expression.

Fiber and phenolic compounds contribution to the hepatoprotective effects of mango diets in rats fed high cholesterol/sodium cholate

The present study evaluated the contribution of mango fiber (MF) and mango phenolic compounds (MP) to the hepatoprotective effect of freeze-dried mango pulp (FDM) cultivar (cv.) "Ataulfo" diets in high cholesterol/sodium cholate (HCC)-fed rats. Male Wistar rats were fed with a HCC diet for 12 weeks, either untreated, or supplemented with MF, MP, FDM, or a control diet (no HCC; n = 6/group). All mango treatments significantly decreased hepatic cholesterol deposition and altered its fatty acid profile, whereas MF and MP mitigated adipose tissue hypertrophy. MF caused a lower level of proinflammatory cytokines (IL-1α/β, IFN-γ, TNF-α) whereas FDM increased the anti-inflammatory ones (IL-4, 6, 10). Mango treatments increased catalase (CAT) activity and its mRNA expression; superoxide dismutase (SOD) activity was normalized by MF and FDM, but its activity was unrelated to its hepatic mRNA expression. Changes in CAT and SOD mRNA expression were unrelated to altered Nrf2 mRNA expression. Higher hepatic PPARα and LXRα mRNA levels were found in MP and MF. We concluded that MF and MP are highly bioactive, according to the documented hepatoprotection in HCC-fed rats; their mechanism of action appears to be related to modulating cholesterol and fatty acid metabolism as well as to stimulating the endogenous antioxidant system.

Evaluation of diphenhydramine in talc induced type 2 diabetes mellitus in Wistar rats

Evaluation of diphenhydramine in talc induced type 2 diabetes mellitus was done in Wistar rats. Oral administration of Talc (10mg/kg)carried out for 21days increased the levels of serum glutamate pyruvate transaminase (SGPT), glutamate oxaloacetate transaminase (SGOT), serum creatinine, blood glucose, urea, uric acid and triglycerides (TGs), but when the animals were treated with diphenhydramine (DPH), the levels of the aforementioned biochemical parameters decreased significantly (p<0.0001). The level of serum cholesterol and high density lipoprotein (HDL) was found to be reduced in Diabetes Mellitus (DM) control and when it was treated with DPH control animals, these makers increased significantly. The study done on DM and Diphenhydramine suggests that Talc increases the blood glucose level at a dose of 10mg/kg (0.14gm) and Diphenhydramine (1mg/kg)reduces the increased blood glucose level. These finding simply that diphenhydramine may be useful in the management of talc induced diabetes.

On the regulatory importance of 27-hydroxycholesterol in mouse liver

27-Hydroxycholesterol (27OH) is a strong suppressor of cholesterol synthesis and a weak activator of LXR in vitro. The regulatory importance of 27OH in vivo is controversial. Here we utilized male mice with increased levels of 27OH either due to increased production (CYP27A1 transgenic mice) or reduced metabolism (Cyp7b1-/- mice). We also used mice lacking 27OH due to a knockout of Cyp27a1. The latter mice were treated with cholic acid to compensate for reduced bile acid synthesis. The effects of the different levels of 27OH on Srebp- and other LXR-regulated genes in the liver were investigated. In the liver of CYP27tg mice we found a modest increase of the mRNA levels corresponding to the LXR target genes Cyp7b1 and Abca1. A number of other LXR-regulated genes were not affected. The effect on Abca1 mRNA was not seen in the liver of Cyp7b1-/- mice. There were little or no effects on cholesterol synthesis. In the liver of the Cyp27-/- mice treated with 0.025% cholic acid there was no significant effect of the knockout on the LXR target genes. In a previous work triple-knockout mice deficient in the biosynthesis of 24S-hydroxycholesterol, 25-hydroxycholesterol and 27OH were shown to have impaired response to dietary cholesterol, suggesting side-chain oxidized oxysterols to be mediators in cholesterol-induced effects on LXR target genes at a transcriptional level (Chen W. et al., Cell Metab. 5 (2007) 73-79). The hydroxylated oxysterol responsible for the effect was not defined. We show here that treatment of wildtype mice with dietary cholesterol under the same conditions as in the above study induced the LXR target genes Lpl, Abcg8 and Srebp1c in wild type mice but failed to activate the same genes in mice lacking 27-hydroxycholesterol due to a knockout of Cyp27. We failed to demonstrate the above effects at the protein level (Abcg8) or at the activity level (Lpl). The results suggest that 27OH is not an important regulator of Srebp- or LXR regulated genes under basal conditions in mouse liver. On the other hand 27OH appears to mediate cholesterol-induced effects on some LXR target genes at a transcriptional level under some in vivo conditions.

Metabolomic Fingerprinting in the Comprehensive Study of Liver Changes Associated with Onion Supplementation in Hypercholesterolemic Wistar Rats

The consumption of functional ingredients has been suggested to be a complementary tool for the prevention and management of liver disease. In this light, processed onion can be considered as a source of multiple bioactive compounds with hepatoprotective properties. The liver fingerprint of male Wistar rats (n = 24) fed with three experimental diets (control (C), high-cholesterol (HC), and high-cholesterol enriched with onion (HCO) diets) was obtained through a non-targeted, multiplatform metabolomics approach to produce broad metabolite coverage. LC-MS, CE-MS and GC-MS results were subjected to univariate and multivariate analyses, providing a list of significant metabolites. All data were merged in order to figure out the most relevant metabolites that were modified by the onion ingredient. Several relevant metabolic changes and related metabolic pathways were found to be impacted by both HC and HCO diet. The model highlighted several metabolites (such as hydroxybutyryl carnitine and palmitoyl carnitine) modified by the HCO diet. These findings could suggest potential impairments in the energy−lipid metabolism, perturbations in the tricarboxylic acid cycle (TCA) cycle and β-oxidation modulated by the onion supplementation in the core of hepatic dysfunction. Metabolomics shows to be a valuable tool to evaluate the effects of complementary dietetic approaches directed to hepatic damage amelioration or non-alcoholic fatty liver disease (NAFLD) prevention.

Anti-atherosclerotic effect of Cynodon dactylon extract on experimentally induced hypercholesterolemia in rats

Cynodon dactylon (Bermuda grass) is a perennial plant traditionally used as an herbal medicine in many countries. In the present study, anti-atherosclerotic property of ethanolic extract of C. dactylon was investigated in the experimentally induced hypercholesterolemia in rats. In this study, 36 male Wistar rats were selected and allocated into six groups (n = 6). The control group received a normal diet, sham group received a high cholesterol diet (HCD; 1.50% cholesterol and 24.00% fat) and other groups received a HCD and ethanolic extract of C. dactylon at low (100 mg kg^-1), moderate (200 mg kg^-1) and maximum (400 mg kg^-1) doses via gavages. The last group received atorvastatin (10 mg kg^-1) through gavage with a HCD. The study period for all groups was six months. At the end of this period, parameters including total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were assessed in the blood samples. Additionally, histopathological and immunohistochemical examinations on coronary and aorta arteries sections were performed. The results showed an increase in vessels wall thickness and proliferation of smooth muscle cells in the HCD group, while these pathological changes were not seen in C. dactylon-treated groups. Treatment of HCD animals with C. dactylon positively changed lipid profile by lowering of TC, TG and LDL-C. The results indicate that C. dactylon prevents from early atherosclerotic changes in the vessels wall.

Differential protection of black-seed oil on econucleotidase, cholinesterases and aminergic catabolizing enzyme in haloperidol-induced neuronal damage of male rats

BACKGROUND

The antipsychotic, haloperidol, is extremely efficient in the treatment of schizophrenia but its application is constrained because of irreversible adverse drug reactions. Hence, in this study, we investigate the differential effects of black seed oil on cholinesterase [acetylcholinesterase (AChE) and butrylcholinesterase (BuChE), ectonucleotidase (5'-nucleotidase), lactate dehydrogenase (LDH) and monoamine oxidase (MAO)] activities and relevant markers of oxidative stress in the cerebrum of haloperidol-induced neuronal-damaged rats.

METHODS

The animals were divided into six groups (n = 10): normal control rats; haloperidol-induced rats: induced rats were pre-, co- and post-treated with black-seed oil respectively, while the last group was treated with extract oil only. The treatment was performed via oral administration and the experiment lasted 14 days.

RESULTS

The results revealed an increase in 5(I) nucleotidase, a marker of adenosine triphosphate (ATP) and adenosine monophosphate (AMP) hydrolysis, as well as AChE, BuChE and MAO activities, with concomitant decrease in LDH activity of cerebrum in induced rats when compared with controls. Also, administration of haloperidol caused systemic oxidative damage and adverse histopathological changes in neuronal cells, indications of mental disorder. The differential treatments with black-seed oil prevented these alterations by increasing LDH and decreasing 5(I) nucleotidase, AChE, BuChE and MAO activities in the cerebrum. Essential oil post-treatment is most efficacious in reversing haloperidol-induced neuronal damage in rat; followed by pre- and cotreatment, respectively.

CONCLUSIONS

We concluded that essential black-seed oil enhanced the wellness of aminergic, purinergic and cholinergic neurotransmissions of haloperidol-induced neuronal damage in rats.

Cholesterol regulatory effects and antioxidant activities of protein hydrolysates from zebra blenny (Salaria basilisca) in cholesterol-fed rats

This study aims to explore the hypocholesterolemic effects and antioxidative activities of zebra blenny protein hydrolysates (ZBPHs) in rats fed with a hypercholesterolemic diet. The rats were fed during eight weeks a standard laboratory diet (normal rats), a high-cholesterol diet (HCD) (1%) or a HCD and orally treated with ZBPHs or undigested zebra blenny proteins (UZBPs) (400 mg per kg per day). Results showed that a hypercholesterolemic diet induced the increase of total cholesterol (TC), triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C). Treatment with ZBPHs increased the level of high-density lipoprotein cholesterol (HDL-C) and decreased significantly the levels of TC, TG, and LDL-C. In addition, ZBPH treatment showed significant normalization of thiobarbituric acid-reactive substance (TBARS) levels as well as catalase, superoxide dismutase (SOD), and glutathione peroxidase (GPx) activities in renal and hepatic tissues. Furthermore, ZBPHs may also exert significant protective effects on liver and kidney functions, evidenced by a marked decrease in the level of serum urea, uric acid, creatinine, alkaline phosphatase (ALP), and alanine aminotransferase (ALAT). Histological studies confirmed that ZBPHs effectively protected the livers and kidneys against hypercholesterolemia-mediated oxidative damage. Therefore, the study strengthens the hypothesis that ZBPHs can be used as novel antioxidants and hypocholesterolemic compounds against hyperlipidemia induced atherosclerosis.

Lipidomic Modulation in Stressed Albino Rats Is Altered by Yolk and Albumen of Quail (Coturnix japonica) Egg and Poultry Feed

Cold and immobilization stressors can generate oxidative stress as well as skeletal muscle fatigue. Free radicals cause oxidative degradation of lipids, proteins, nucleic acids, and carbohydrates molecules, thereby compromising cell integrity and function. Quail egg had been described as being very functional biochemically, due to the essential biomolecules it contains in very regulated quantity. This study was aimed for evaluating the dietary effect of the egg on lipid profile parameters on selected tissues. The antilipidemic properties of the egg yolk and albumen and poultry (layers) feed were determined in selected tissues in male albino rats assaulted with cold immobilization stress induced on them at 4°C for 2 hours, while diazepam was used as standard antistress drug. Antilipidemic activities were evaluated by lipid profile modulation (HDL, LDL, TRIG., and T-CHOL.). Quantitative and qualitative analyses of fatty acids profile of the yolk hexane-extract were determined by Gas Chromatography and Mass Spectrophotometry (GC-MS). The ameliorative impacts of diazepam (2.5 and 5.0 mg/mL/kg BW), yolk (5 and 10 mL/kg BW), albumen (5 and 10 mL/kg BW), and the feed (5-10 mg/kg BW) were competitively (p < 0.05) specific for each of the tissues. The result of the study suggested yolk and albumen of quail egg and poultry feed as antistress agents as well as lipid modulators.

Effects on Liver Lipid Metabolism of the Naturally Occurring Dietary Flavone Luteolin-7-glucoside

Disruptions in whole-body lipid metabolism can lead to the onset of several pathologies such as nonalcoholic fatty liver disease (NAFLD) and cardiovascular diseases (CVDs). The present study aimed at elucidating the molecular mechanisms behind the lipid-lowering effects of the flavone luteolin-7-glucoside (L7G) which we previously showed to improve plasma lipid profile in rats. L7G is abundant in plant foods of Mediterranean diet such as aromatic plants used as herbs. Results show that dietary supplementation with L7G for one week induced the expression of peroxisome proliferator-activated receptor-alpha (PPAR-α) and of its target gene carnitine palmitoyl transferase 1 (CPT-1) in rat liver. L7G showed a tendency to decrease the hepatic expression of sterol regulatory element-binding protein-1 (SREBP-1), without affecting fatty acid synthase (FAS) protein levels. Although SREBP-2 and LDLr mRNA levels did not change, the expression of HMG CoA reductase (HMGCR) was significantly repressed by L7G. L7G also inhibited this enzyme's in vitro activity in a dose dependent manner, but only at high and not physiologically relevant concentrations. These results add new evidence that the flavone luteolin-7-glucoside may help in preventing metabolic diseases and clarify the mechanisms underlying the beneficial health effects of diets rich in fruits and vegetables.

Protective effects of farnesoid X receptor (FXR) on hepatic lipid accumulation are mediated by hepatic FXR and independent of intestinal FGF15 signal

BACKGROUND & AIMS

There is a growing evidence that bile acids are involved in the regulation of triglyceride-, cholesterol-homoeostasis and fat absorption. In this study organ-specific Fxr knockout mice were used to further investigate the influence of farnesoid X receptor FXR in lipogenesis.

METHODS

Liver- and intestine-specific Fxr knockout mice were fed a 1% cholesterol diet for 28 days. Histological examination of frozen tissue sections included Sudan III/H&E, BODIPY staining and liver X receptor (LXR) immunohistochemistry. Liver triglycerides, serum cholesterol, serum bile acids and nuclear LXR protein were measured. mRNA expression of several genes involved in bile acid-, cholesterol-homoeostasis and lipogenesis was quantified by real-time PCR.

RESULTS

Hepatic FXR deficiency contributes to lipid accumulation under 1% cholesterol administration which is not observed in intestinal Fxr knockout mice. Strong lipid accumulation, characterized by larger vacuoles could be observed in hepatic Fxr knockout sections, while intestinal Fxr knockout mice show no histological difference to controls. In addition, these mice have the ability to maintain normal serum cholesterol and bile acid levels. Hepatic Fxr knockouts were characterized by elevated triglycerides and bile acid levels. Expression level of LXR was significantly elevated under control and 1% cholesterol diet in hepatic Fxr knockout mice and was followed by concomitant lipogenic target gene induction such as Fas and Scd-1. This protective FXR effect against hepatic lipid accumulation was independent of intestinal Fgf15 induction.

CONCLUSION

These results show that the principal site of protective bile acid signalling against lipid accumulation is located in the liver since the absence of hepatic but not intestinal FXR contributes to lipid accumulation under cholesterol diet.

Monascus purpureus-fermented Thai glutinous rice reduces blood and hepatic cholesterol and hepatic steatosis concentrations in diet-induced hypercholesterolemic rats

BACKGROUND

Red yeast rice (RYR) is a fermented product used as a food supplement to promote blood circulation and lower blood cholesterol levels in eastern Asia. Interestingly, monacolin K is the most active compound in RYR that proved to inhibit HMG-CoA reductase in the cholesterol biosynthesis pathway.

METHODS

The hypocholesterolemic effects of oral administration of Thai RYR, produced by fermentation of Thai glutinous rice (Oryza sativa L. var. Niaw San-pah-tawng) with Monascus purpureus CMU 002U, were determined in normal and hypercholesterolemic rats. The rats were divided into six groups, and fed two different kinds of diet. Groups I-II, normal rats fed with a normal diet (SP-diet), were treated with distilled water (SP-control) and 2.0 g/kg/day of RYR extract (SP-2 g). In Groups III-VI, the rats were rendered hypercholesterolemic by feeding them a high fat and cholesterol diet (HFC-diet), and were treated with distilled water (HFC-control), 1.0 g/kg/day (HFC-1 g), 2.0 g/kg/day (HFC-2 g) of RYR extract, and 5.0 mg/kg/day of rosuvastatin (HFC-rosuvastatin) for 30 days, respectively.

RESULTS

The RYR extract significantly decreased the concentrations of serum total cholesterol and low density lipoprotein cholesterol (LDL-C), atherosclerotic index, LDL-C/HDL-C ratio and hepatic cholesterol levels in both HFC-1 g and HFC-2 g groups (p < 0.05) as compared with the HFC-control group, and with no significant change in high density lipoprotein cholesterol (HDL-C) concentrations among all six groups. The reduction of serum TC and LDL-C also paralleled the observed changes in mRNA expressions of the genes involved in cholesterol biosynthesis and homeostasis in the liver. The hypercholesterolemic rats treated with RYR extract were significantly higher in LDLR and HMGR expression, but lower in CYP7A1 expression when compared to the untreated hypercholesterolemic rats (HFC-control) (p < 0.05). The hepatic injuries in hypercholesterolemic rats were also obviously alleviated by RYR extract.

CONCLUSIONS

The extract of Thai RYR possessed potent hypocholesterolemic and anti-atherogenic activities in diet-induced hypercholesterolemic rats. The possible mechanism involving cholesterol-lowering potential of the extract might contribute to its ability to increase LDL-C endocytosis in hepatocyte and to competitively inhibit HMG-CoA reductase, a key enzyme for cholesterol biosynthesis in liver.

Cholesterol-cholate-butterfat diet offers multi-organ dysfunction in rats

Background

Comparable to commercial expensive high-fat diets, cholesterol-cholate-butterfat (CCB) diet has also been used to induce hyperlipidemia in rats. Our objective was to explore its influence on multiple organs. Consequence of fasting was also analysed.

Methods

Rats in groups 1 and 2 received normal diet (ND) whereas groups 3 and 4 received CCB-diet. Food was withdrawn daily for two hours from groups 2 (ND-F) and 4 (CCB-F). Blood was collected at fourth and sixth week for biochemical estimation; Morris water maze was done in the sixth week for learning ability and memory; after which aortae were isolated for vascular reactivity.

Results

Apart from hyperlipidemia, CCB also induced hyperglycemia with marked increase in hepatic enzymes: gamma-glutamyl transferase (GGT), alanine and aspartate aminotransferase (ALT and AST); and vascular biomarkers: uric acid (UA), phosphorus and alkaline phosphatase (ALP). Isolated aortae, pre-contracted with phenylephrine, were less responsive to acetylcholine indicating endothelial dysfunction – serum nitric oxide (NO) production was limited with subsequent inhibition of endothelial NO synthase. CCB diet also compromised learning ability. CCB-coupled fasting potentiated hyperlipidemia but prevented memory-loss.

Conclusion

We introduce CCB-diet for multi-organ dysfunction in rats, and propose its use for research on cardiovascular diseases and associated manifestations involving immense interplay of integrated pathways.

Electronic supplementary material

The online version of this article (doi:10.1186/1476-511X-13-194) contains supplementary material, which is available to authorized users.

Role of PPARα and HNF4α in stress-mediated alterations in lipid homeostasis

Stress is a risk factor for several cardiovascular pathologies. PPARα holds a fundamental role in control of lipid homeostasis by directly regulating genes involved in fatty acid transport and oxidation. Importantly, PPARα agonists are effective in raising HDL-cholesterol and lowering triglycerides, properties that reduce the risk for cardiovascular diseases. This study investigated the role of stress and adrenergic receptor (AR)-related pathways in PPARα and HNF4α regulation and signaling in mice following repeated restraint stress or treatment with AR-antagonists administered prior to stress to block AR-linked pathways. Repeated restraint stress up-regulated Pparα and its target genes in the liver, including Acox, Acot1, Acot4, Cyp4a10, Cyp4a14 and Lipin2, an effect that was highly correlated with Hnf4α. In vitro studies using primary hepatocyte cultures treated with epinephrine or AR-agonists confirmed that hepatic AR/cAMP/PKA/CREB- and JNK-linked pathways are involved in PPARα and HNF4α regulation. Notably, restraint stress, independent of PPARα, suppressed plasma triglyceride levels. This stress-induced effect could be attributed in part to hormone sensitive lipase activation in the white adipose tissue, which was not prevented by the increased levels of perilipin. Overall, this study identifies a mechanistic basis for the modification of lipid homeostasis following stress and potentially indicates novel roles for PPARα and HNF4α in stress-induced lipid metabolism.

Improving the growth performance and cholesterol metabolism of rainbow trout (Oncorhynchus mykiss) fed soyabean meal-based diets using dietary cholesterol supplementation

A 9-week feeding trial was conducted to evaluate the effects of dietary cholesterol supplementation at different levels (0, 0·3, 0·6, 0·9, 1·2 and 1·5 %) on growth and cholesterol metabolism of rainbow trout (Oncorhynchus mykiss) fed soyabean meal (SBM)-based diets. Daily growth coefficient (DGC) steadily increased when the supplemental cholesterol was increased by up to 1·2 %, but declined upon further addition. The total cholesterol (TC), HDL-cholesterol (HDL-C) and LDL-cholesterol (LDL-C) levels in plasma generally increased when the supplemental cholesterol was increased by up to 1·2 %. Thereafter, the TC level reached a plateau, the LDL-C level showed a marked decline, whereas the HDL-C level continued to increase. Dietary cholesterol supplementation generally increased the total lipid and cholesterol levels in liver; the total lipid and TAG levels in muscle; the TC, free cholesterol, cholesteryl ester and total bile acid levels in intestinal contents; and the triiodothyronine and Ca levels in plasma. However, significant differences were mainly observed with high levels of supplemental cholesterol (0·9-1·5 %). Low levels of supplemental cholesterol (0·3-0·9 %) decreased hepatic 3-hydroxy-3-methyl-glutaryl-CoA reductase and cholesterol 7α-hydroxylase activities, but high levels of supplemental cholesterol (1·5 %) increased hepatic acyl-CoA:cholesterol acyl transferase and cholesterol 7α-hydroxylase activities. These results suggest that rainbow trout fed SBM-based diets have a certain 'cholesterol-buffering capacity', which in turn suggests the possibility of the inhibition of exogenous cholesterol absorption and/or inadequate endogenous production of cholesterol in trout fed SBM-based diets. DGC increased steadily with increasing supplemental cholesterol level up to 1·2 %, and the growth-promoting effects might be related to the alleviation of the negative effects caused by a soyabean diet and/or make up for the deficiency of endogenous cholesterol in rainbow trout.

An atherogenic diet decreases liver FXR gene expression and causes severe hepatic steatosis and hepatic cholesterol accumulation: effect of endurance training

PURPOSE

The aim of this study was to determine the effects of an atherogenic diet (AD; 40 % lipid, 1.25 % cholesterol, kcal) on triglyceride (TAG) and cholesterol accumulation in liver and on gene expression of liver X receptor (LXR) and farnesoid X receptor (FXR) and their target genes and to observe if these responses are affected by endurance training.

METHODS

Sprague-Dawley rats (n = 32) were divided into two groups and randomly assigned to an AD or a standard diet (SD) for 7 weeks. Half of the rats in each group were assigned to an exercise training program for 5 days/week.

RESULTS

The AD resulted in a large (P < 0.01) accumulation in liver TAG (4×) along with elevated liver and plasma cholesterol without any gain in peripheral fat mass. The liver TAG and cholesterol accumulations were associated with an important reduction (P < 0.01; 60 %) in FXR, but no change in LXR transcripts. Accompanying the reduction in FXR gene expression, we found an increase (P < 0.001) in SREBP-1c and a decrease (P < 0.01) in MTP mRNAs suggesting an increased lipogenesis and a reduced VLDL production, respectively. The AD was also associated with lower HMG-CoA-r, squalene synthase, and ABCG8 transcripts (P < 0.001). In the intestine, exercise training resulted in higher NPC1L1, ABCG5, and ABCG8 in SD-fed animals, while all these increases were suppressed under the AD feeding.

CONCLUSIONS

It is concluded that dietary cholesterol favors liver TAG and cholesterol accumulations associated with an important reduction in FXR transcripts.

Rice protein improves adiposity, body weight and reduces lipids level in rats through modification of triglyceride metabolism

Background

To elucidate whether rice protein can possess a vital function in improving lipids level and adiposity, the effects of rice proteins extracted by alkaline (RP-A) and α-amylase (RP-E) on triglyceride metabolism were investigated in 7-week-old male Wistar rats fed cholesterol-enriched diets for 2 weeks, as compared with casein (CAS).

Results

Compared with CAS, plasma concentrations of glucose and lipids were significantly reduced by RP-feeding (P < 0.05), as well as hepatic accumulation of lipids (P < 0.05). RP-A and RP-E significantly depressed the hepatic activities of fatty acid synthase (FAS), glucose 6-phosphate dehydrogenase (G6PD) and malate dehydrogenase (MDH) (P < 0.05), whereas the activities of lipoprotein lipase (PL) and hepatic lipase (HL) were significantly stimulated (P < 0.05), as compared to CAS. Neither lipids level nor activities of enzymes were different between RP-A and RP-E (P > 0.05). There was a significant positive correlation between protein digestibility and deposit fat (r = 0.8567, P < 0.05), as well as the plasma TG concentration (r = 0.8627, P < 0.05).

Conclusions

The present study demonstrates that rice protein can modify triglyceride metabolism, leading to an improvement of body weight and adiposity. Results suggest that the triglyceride-lowering action as well as the potential of anti-adiposity induced by rice protein is attributed to upregulation of lipolysis and downregulation of lipogenesis, and the lower digestibility of rice protein may be the main modulator responsible for the lipid-lowering action.

The fat and protein fractions of freshwater clam (Corbicula fluminea) extract reduce serum cholesterol and enhance bile acid biosynthesis and sterol excretion in hypercholesterolaemic rats fed a high-cholesterol diet

We investigated whether the fat and protein fractions of freshwater clam (Corbicula fluminea) extract (FCE) could ameliorate hypercholesterolaemia in rats fed a high-cholesterol diet. We also explored the mechanism and the components that exert the hypocholesterolaemic effect of FCE. The doses of the fat and protein fractions were equivalent to those in 30 % FCE. The fat and protein fractions of FCE, two major components of FCE, significantly reduced the serum and hepatic cholesterol levels. The fat fraction more strongly reduced serum cholesterol levels than the same level of total FCE. The excretion of faecal neutral sterols increased in rats fed the total the FCE and the fat fraction of FCE. On the other hand, faecal bile acid levels were greater in rats fed the total FCE and the fat and protein fractions of FCE than in control animals. The hepatic gene expression of ATP-binding cassette transporter G5 and cholesterol 7α-hydroxylase was up-regulated by the administration of the total FCE and both the fat and protein fractions of FCE. These results showed that the fat and protein fractions of FCE had hypocholesterolaemic properties, and that these effects were greater with the fat fraction than with the protein fraction. The present study indicates that FCE exerts its hypocholesterolaemic effects through at least two different mechanisms, including enhanced excretion of neutral sterols and up-regulated biosynthesis of bile acids.