Fat Content Of Rats Research Articles

Correlation of Lipin gene expression with hepatic fat content in rats with intrauterine growth retardation

To study the correlation of the expression of Lipin1 in visceral adipose tissue and Lipin2 in liver tissue with hepatic fat content in rats with intrauterine growth retardation (IUGR). Pregnant rats were given a low-protein (10% protein) diet during pregnancy to establish a model of IUGR in neonatal rats. The pregnant rats in the control group were given a normal-protein (21% protein) diet during pregnancy. The neonatal rats were weighed and liver tissue was collected on day 1 and at weeks 3, 8, and 12 after birth, and visceral adipose tissue was collected at weeks 3, 8, and 12 after birth. The 3.0T 1H-magnetic resonance spectroscopy was used to measure hepatic fat content at weeks 3, 8, and 12 after birth. Real-time PCR was used to measure mRNA expression levels of Lipin2 in liver tissue and Lipin1 in visceral adipose tissue. Western blot was used to measure protein levels of Lipin2 in liver tissue and Lipin1 in visceral adipose tissue. A Pearson correlation analysis was performed to investigate the correlation of mRNA and protein expression of Lipin with hepatic fat content. The IUGR group had significantly higher mRNA and protein expression levels of Lipin1 in visceral adipose tissue than the control group at weeks 3, 8, and 12 after birth (P<0.05). Compared with the control group, the IUGR group had significantly lower mRNA and protein expression levels of Lipin2 in liver tissue on day 1 after birth and significantly higher mRNA and protein expression levels of Lipin2 at weeks 1, 3, 8, and 12 after birth (P<0.05). At week 3 after birth, there was no significant difference in hepatic fat content between the IUGR and control groups (P>0.05), while at weeks 8 and 12 after birth, the IUGR group had a significantly higher hepatic fat content than the control group (P<0.05). The protein and mRNA expression levels of Lipin1 were positively correlated with hepatic fat content (r=0.628 and 0.521 respectively; P<0.05), and the protein and mRNA expression levels of Lipin2 were also positively correlated with hepatic fat content (r=0.601 and 0.524 respectively; P<0.05). Upregulation of the mRNA and protein expression levels of Lipin1 in visceral adipose tissue and Lipin2 in liver tissue can increase hepatic fat content in rats with IUGR and may be associated with obesity in adulthood.

Quantitative Evaluation of Nonalcoholic Fatty Liver in Rat by Material Decomposition Techniques using Rapid-switching Dual Energy CT

To evaluate the material decomposition (MD) techniques in rapid kVp switching dual-energy CT (rsDECT) for quantifying liver fat content in rats with nonalcoholic fatty liver. Fifty male Sprague-Dawley (SD) rats were divided into study group (n=37) and control group (n=13) and underwent rsDECT examination at different intervals. All the data analysis was performed using AW4.7 workstation. The fat contents under the traditional fat(water), fat(blood), and fat(muscle) material decomposition (MD) images and the fat volume fraction (FVF) from the liver fat maps generated using multi-material decomposition (MMD) technique were measured. The pathological grades (grade 0, 1, 2 and 3) of fatty liver were determined after euthanasia. The measurement differences among different grades and the correlation of measurements with different grades was analyzed using ANOVA and Spearman correlation, respectively. A receiver operating characteristics (ROC) curve was used to analyze the diagnostic efficacies of fat contents and FVF. There were statistically significant differences in FVF and fat contents under fat(water), fat(blood), fat(muscle) based MD images among different grades. These values correlated well with the pathological grades (R-value: 0.90, 0.75, 0.79, 0.80, all p <0.001), with FVF having the highest correlation. The area-under-the-curve in ROC of using FVF was the highest, with the cut-off value of 0.92 for sensitivity of 89.2% and specificity of 100%. The rsDECT MD techniques could quantitatively evaluate the fat content of fatty liver in rat, with the FVF from MMD having the highest correlation with pathological grades.

Caloric Restriction Prevents Metabolic Dysfunction and the Changes in Hypothalamic Neuropeptides Associated with Obesity Independently of Dietary Fat Content in Rats.

Energy restriction is a first therapy in the treatment of obesity, but the underlying biological mechanisms have not been completely clarified. We analyzed the effects of restriction of high-fat diet (HFD) on weight loss, circulating gut hormone levels and expression of hypothalamic neuropeptides. Ten-week-old male Wistar rats (n = 40) were randomly distributed into four groups: two fed ad libitum a normal diet (ND) (N group) or a HFD (H group) and two subjected to a 25% caloric restriction of ND (NR group) or HFD (HR group) for 9 weeks. A 25% restriction of HFD over 9 weeks leads to a 36% weight loss with regard to the group fed HFD ad libitum accompanied by normal values in adiposity index and food efficiency ratio (FER). This restriction also carried the normalization of NPY, AgRP and POMC hypothalamic mRNA expression, without changes in CART. Caloric restriction did not succeed in improving glucose homeostasis but reduced HFD-induced hyperinsulinemia. In conclusion, 25% restriction of HFD reduced adiposity and improved metabolism in experimental obesity, without changes in glycemia. Restriction of the HFD triggered the normalization of hypothalamic NPY, AgRP and POMC expression, as well as ghrelin and leptin levels.

Effect of Walnut Meal Peptides on Hyperlipidemia and Hepatic Lipid Metabolism in Rats Fed a High-Fat Diet.

As a natural active substance that can effectively improve blood lipid balance in the body, hypolipidemic active peptides have attracted the attention of scholars. In this study, the effect of walnut meal peptides (WMP) on lipid metabolism was investigated in rats fed a high-fat diet (HFD). The experimental results show that feeding walnut meal peptides counteracted the high-fat diet-induced increase in body, liver and epididymal fat weight, and reduce the serum concentrations of total cholesterol, triglycerides, and LDL-cholesterol and hepatic cholesterol and triglyceride content. Walnut meal peptides also resulted in increased HDL-cholesterol while reducing the atherosclerosis index (AI). Additionally, the stained pathological sections of the liver showed that the walnut meal peptides reduced hepatic steatosis and damage caused by HFD. Furthermore, walnut meal peptide supplementation was associated with normalization of elevated apolipoprotein (Apo)-B and reduced Apo-A1 induced by the high-fat diet and with favorable changes in the expression of genes related to lipid metabolism (LCAT, CYP7A1, HMGR, FAS). The results indicate that walnut meal peptides can effectively prevent the harmful effects of a high-fat diet on body weight, lipid metabolism and liver fat content in rats, and provide, and provide a reference for the further development of walnut meal functional foods.

Correlations of PPARα and PPARγ expressions with 1H-MRS quantified hepatic fat content in pups of rats that experienced intrauterine growth restriction

Background: Proton magnetic resonance spectroscopy (1H-MRS) measurement of hepatic fat content in intrauterine growth restriction rats has rarely been reported. This study was to explore the association of peroxisome proliferator-activated receptor alpha and gamma (PPARα and PPARγ) expression with 1H-MRS quantified hepatic fat content in offspring of rats that experienced intrauterine growth restriction (IUGR).Methods and findings: IUGR was established by feeding a low-protein diet to female rats during pregnancy. Male pups of IUGR rats were weighed, liver tissues were collected at the ages of 1 day and 1, 3, 8 and 12 weeks post birth. Visceral adipose tissues (VATs) were collected at 3, 8, and 12 weeks post birth. Male pups also received conventional magnetic resonance imaging and 1H-MRS using a 3.0 T whole-body MR scanner at 3, 8, and 12 weeks post birth. The peak area ratios in the MR spectra were calculated to determine hepatic lipid content. The expression of PPARα protein was detected by Western blot. The expression of PPARα mRNA was measured by real-time quantitative PCR. Significantly lower PPARα protein and mRNA expression were observed in liver tissues of male pups of IUGR rats at 1 day and 1, 3, 8, and 12 weeks post birth compared to male pups of control rats. In contrast, significantly higher PPARγ protein and mRNA expression were observed in VATs of male pups of IUGR rats at 3, 8, and 12 weeks post birth compared to male pups of control rats. PPARα protein and mRNA expression in the liver negatively correlated with the hepatic fat content (r = −0.611, −0.607, respectively), whereas PPARγ protein and mRNA expression in VATs positively correlated with the hepatic fat content (r = 0.659, 0.668, respectively).Conclusion: 1H-MRS allows noninvasive assessment of hepatic fat content in rats. PPARα protein and mRNA expression were significantly decreased in the livers of rats, whereas PPARγ protein and mRNA expression was significantly increased in VATs in pups of IUGR rats.

Increased Total Scavenger Capacity and Decreased Liver Fat Content in Rats Fed Dehydroepiandrosterone and Its Sulphate on a High-Fat Diet

Background: Weak androgens have an antioxidant effect in vitro which is represented as a beneficial change in the antioxidant status. Objective: Our aim was to clarify whether dehydroepiandrosterone (DHEA) and dehydroepiandrosterone-sulphate (DHEAS) oral administration results in beneficial antioxidant changes in Sprague-Dawley adult male rats in vivo. Methods: Groups of experimental animals were fed a high-fat or a normal-fat diet and treated with DHEA or DHEAS in the drinking fluid. The control group was fed a high-fat diet together with untreated drinking fluid. Total scavenger capacity (TSC) was measured before and after 4 weeks of treatment in blood samples using a chemiluminometric assay. Fat content, superoxide dismutase (SOD), catalase and glutathione S-transferase (GST) activity in the liver were determined by Sudan staining and spectrophotometric assessments, respectively, from the fresh frozen tissue. Results: DHEA and the DHEAS treatment showed significantly increased TSC in the groups fed a high-fat diet. The control group and the DHEA- or DHEAS-treated groups on normal diets showed no significant changes in TSC. The total score of liver fat content in the high-fat diet groups showed a marked positivity with Sudan staining, and the groups treated with DHEA or DHEAS had a markedly decreased amount of fat in the liver slides compared to the untreated group on the high-fat diet. Liver SOD activity was decreased in all high-fat diet groups and elevated only in the groups on a normal diet with DHEA or DHEAS treatment. Liver catalase and GST activities were decreased in the groups where TSC was significantly increased. Conclusion: Our results support the hypothesis that DHEA and DHEAS supplementation can improve the antioxidant status in lipid-rich dietary habits.

Long-term effects of exogenous leptin on body weight and fat in post-obese female rats

This study was designed to test the hypothesis that short-term leptin infusion during the post-obese refeeding phase of weight-reduced rats would reduce the rate of weight regain and, as a result, reduce the final body weight and fat content in weight-reduced rats. Ninety-six female Wistar rats were divided into four groups: (1) LFCON (low-fat control) group: Rats in this group were fed the control low-fat (LF) diet ad lib for the entire study period. (2) HFCON (high-fat control) group: Rats in this group were fed the high-fat (HF, 40% fat) diet ad lib for the study period. (3) HFRLP (high-fat fed, weight-reduced, leptin treatment) group: Obese rats in this group were weight-reduced and received leptin infusion for 2 weeks (miniosmotic pumps, 0.5 μg/kg/day) during the post-obese refeeding period. (4) HFRSM (high-fat fed, weight-reduced, sham control) group: Rats in this sham-control group were treated the same as the rats in the HFRLP group with the exception that no leptin was actually infused during the first 2 weeks of refeeding period. The results demonstrated that 2 weeks of leptin treatment during the early refeeding phase did not prevent weight regain in weight-reduced rats, but it significantly reduced body fat content in these rats as compared to ad lib fed obese control rats. One cycle of weight reduction and regain did not alter the body weight and body fat content in HFRSM rats when compared to obese control rats. Therefore, leptin treatment was effective in reducing body fat content in post-obese rats for up to 7 weeks, but the long-term effect of short-term leptin treatment needs to be further examined.

Nutritional hepatic steatosis and mortality after burn injury in rats

To investigate the effects of diet composition and starvation on hepatic steatosis and mortality after severe burn injury in rats. Experiment 1: rats received either normal chow (55 cent of energy carbohydrates, 14 cent fat, 31 cent protein), a high-fat (40 cent carbohydrates, 40 cent fat, 20 cent protein), or a high-carbohydrate diet (81 cent carbohydrates, 4 cent fat, 15 cent protein) ad libitum for 6 days. Another three groups received these diets ad libitum for 6 days after 48|h starvation. Experiment 2: mortality after 60 cent total body surface area scald burn was determined in a control group of rats and a group with nutritionally induced hepatic steatosis. Hepatic steatosis was induced by feeding the rats a high-fat diet (40 cent carbohydrates, 4 cent fat, 15 cent protein) ad libitum for 6 days. Without starvation, liver triglyceride content (mg/g liver) increased in response to the high-fat diet (25.6'6.9) compared to normal chow (9.4'3.8; P < 0. 05); the high-carbohydrate diet had no influence on liver triglyceride content (12.4'3.7). Refeeding after starvation resulted in elevated (P < 0.05) liver triglyceride content in the high-fat (18.8'8.3) and the high-carbohydrate group (28.7'14.4 vs control 6. 7'3.7). Liver triglyceride content correlated (R2=0.72; P < 0.05) to non-protein energy intake but not to total energy intake. Burn caused 33 cent mortality in the hepatic steatosis group and no deaths in the control group (P < 0.05). Diet composition and preceding starvation independently manipulate hepatic fat content in rats. Hepatic steatosis increases mortality after burn injury. Thus, nutritional interventions to reduce hepatic fat accumulation may be beneficial.

Ageing, exercise and food restriction: effects on body composition

This study was undertaken to reevaluate the effect of ageing on body composition and to compare the effects of exercise and food restriction on body fat content in rats. Body fat content increased progressively between ages 12 and 28 months in sedentary freely eating male Long-Evans rats. A program of 3 h of swimming/day caused body weight to plateau at a level ∼20% below that of the freely eating sedentary rats, primarily due to a more than 100 g lower body fat content in the swimmers. Lean body mass and protein content decreased progressively with ageing; in the sedentary animals, this decrease was significant by 18 months. The swimming protected against the decline in lean body mass and protein content up to age 18 months, but did not prevent a large decrease in lean body mass between ages 18 and 24 months. Food restriction that kept the sedentary rats at the same weight as the swimmers had its major effect on body fat content, which was ∼40% lower than in the sedentary freely eating rats at all ages. The differences in body composition between the swimmers and food restricted sedentary animals were relatively small and consisted primarily of a lower body fat content in the swimmers. In conclusion, our results show that lean body mass declines with ageing in rats and that this loss of lean tissue is counterbalanced by an increase in fat. Exercise is highly effective in minimizing the increase in body fat, and may delay the decline in lean body mass, with ageing.

Effects of addition of sulfur-containing amino acids and their catabolites to a low protein diet on liver fat content in rats.

To investigate the effects of catabolites of sulfur-containing amino acids on the liver fat content, rats fed a protein-free or 10% casein diet were orally or intraperitoneally administered sulfur-containing amino acids and their catabolites. Force-feeding of the protein-free diet supplemented with 0.01 and 0.05% methionine reduced the excretion of urinary nitrogen, but it did not affect the liver fat content. Supplementation with 0.2% methionine induced significant liver fat accumulation accompanied with remarkable increases in the concentrations of nonprotein sulfhydryl (NP–SH) and taurine in the liver. The effects of the addition of 0.2% cystine HC1 to the protein-free diet were similar to those of 0.2% methionine. Force-feeding of the protein-free diet supplemented with 0.2% cysteine sulfinic acid or 0.2% thiopyruvate did not bring about any changes in the concentrations of sulfur-containing metabolites and fat content in the liver and the excretion of urinary nitrogen. On the contrary supplementation...

Effect of insulin and cortisone on weight gain, protein and fat content of rats.

Male Wister rats weighing 240 ± 2 gm show an average protein and fat content of 41.6 gm, and 13.1 gm. During a period of normal growth, the body weight increases within 14 days to 311 gm, the protein content to 57 gm, and the fat content to 21.7 gm. Several groups of rats were subjected to experimental procedures for 14 days, after having reached a body weight of 240 gm. Administration of protamine zine insulin (12 u/day) greatly enhanced weight gain, and deposition of excess fat, without affecting accumulation of body protein. Cortisone (5 mg/day) produced variable results. Diminished gain of body weight and total body protein occurred in 60% of the animals while accumulation of body fat was normal. Some rats lost weight and body protein but comparatively less fat than animals losing fat due to food restriction. Weight loss was most frequently observed in rats with visible infections. Simultaneous administration of insulin (12 u/day) did not alter the cortisone effect on body protein but markedly increased accumulation of body fat. One hundred twenty units per day accelerated gain of body fat still more. Values were observed comparable to those found in rats receiving insulin only. The amount of total body fat closely paralleled the amount of adipose tissue the composition of which was not significantly altered by any of the hormonal manipulations.