Qualitative regional differences in adipose tissue growth and cellularity in male Wistar rats fed ad libitum

1998 ◽  
Vol 274 (5) ◽  
pp. R1460-R1467 ◽  
Author(s):  
M. DiGirolamo ◽  
J. B. Fine ◽  
K. Tagra ◽  
R. Rossmanith

Adipose tissue grows primarily by a combination of increases in fat cell volume (hypertrophy) and in fat cell number (hyperplasia), but the regional growth pattern of white adipose tissue depots in animal species and in the human is still unclear. In this study we characterized fully the age-related changes in adipose tissue growth, composition, and cellularity of four fat depots of male Wistar rats that varied in age from 7 wk to 15 mo and in body weight from 178 to 808 g. Body weight and the weight of each of the four adipose depots studied (epididymal, mesenteric, subcutaneous inguinal, and retroperitoneal) increased progressively with age and ad libitum feeding. Comparison of the cellularity of the four adipose depots, however, showed remarkable and significant differences in the pattern of growth within the same animals. The cumulative growth of the two intra-abdominal fat depots (mesenteric and epididymal) was due mostly to hypertrophy (increases in cell volume of 83 and 64%, respectively), whereas the growth of the other two depots (retroperitoneal and inguinal) was due predominantly to hyperplasia (increases in cell number of 58 and 65%, respectively). These findings uncover major and unexpected regional differences in the modulation of adipose tissue growth within aging animals fed ad libitum and suggest local, region-specific regulatory controls of this growth.

1980 ◽  
Vol 43 (1) ◽  
pp. 27-31 ◽  
Author(s):  
Patricia M. Harris

1. Male Wistar rats were allocated at birth to foster mothers in litters of three, nine or sixteen. At weaning animals from each litter size were ad lib.-fed on a stock diet. Further animals from litters of nine and sixteen were fed on the stock diet in restricted amounts until 12 weeks of age and then rehabilitated by being allowed ad lib. access to the stock diet.2. Five animals from each group were killed at 24 weeks of age and the size and number of cells determined in four specific fat depots.3. Animals reared in litters of sixteen and further undernourished from 3 to 12 weeks (group L16/U) had significantly fewer fat cells at all sites studied than animals reared in litters of three and ad lib.-fed. Group L16/U animals also had significantly fewer observable fat cells at the epididymal site than ad lib.-fed animals reared in litters of nine. These results differ from those found in the Black and White Hooded rat where, after similar treatments, no significant differences in observable fat cell number were found.


1990 ◽  
Vol 259 (6) ◽  
pp. R1117-R1125 ◽  
Author(s):  
F. D. Newby ◽  
M. DiGirolamo ◽  
G. A. Cotsonis ◽  
M. H. Kutner

We analyzed retrospectively data from 148 chow-fed male Wistar rats killed between the age of 6 wk and 2 yr while varying in body weight from 136 to 917 g. The purpose of this study was to clarify the relationship of body weight and body lipid content with the composition and cellularity of the epididymal and retroperitoneal fat depots. A positive linear association was found between body weight and body water or fat-free dry residue, whereas total body lipid exhibited a curvilinear relationship with body weight. The weight of the epididymal pads was linearly related to body weight but not to body lipid. In contrast, retroperitoneal pad weight was exponentially related to body weight and paralleled total body lipid. A strong linear correlation was found between total body lipid and weight (r = 0.959) or depot lipid content (r = 0.967) of the retroperitoneal fat pads. In this rat model of aging and spontaneous obesity, significant regional differences exist in adipose depot composition and cellularity. A practical outcome of this study is a simple and accurate prediction of body lipid content from the gravimetric determination of the retroperitoneal fat depots.


2021 ◽  
Author(s):  
Michael A. Olamoyegun ◽  
Folasade O. Ajao ◽  
Marcus O. Iyedupe

Abstract Background: Obesity greatly increases the risk of metabolic diseases and preventive approaches for obesity are often inadequate to effectively prevent and manage the diseases. Altering feeding time strategy intervention decreases caloric intake without calorie counting and may be an effective therapy. Therefore, this study investigates the effect of 4-h time restricted feeding on body weight, leptin concentration and lipid profile in healthy non-obese male Wistar rats. Methods: Rats placed on time-restricted feeding (TRF) regimen had freely access to food for 4 hour per day at designated periods. Twenty four rats divided into four groups (n=6) were used. Group I animals were placed on a 4 hour per day TRF between 8am-12noon. Group II rats were also placed on a 4 hour per day TRF between 12noon-4pm. Group III rats also placed on a 4 hour per day TRF between 8pm-12 midnight while Group IV rats had access food and water ad libitum. This diet strategy resembles taking only breakfast, lunch or dinner once a day. The study lasted for a period of 4 weeks with daily food intake and weekly body weight determined throughout the period. At the end of the experimental period, blood glucose, lipid profile and leptin concentration were assessed. SPSS 21.0 package was used for data analysis, one-way analysis of variance (ANOVA) was used to compare the mean values of variables among the groups and bonferroni’s posthoc test was used for significance of pair wise comparisons of mean values among the groups. Significance was set at p < 0.05.Results: In this study, the body weights and leptin concentrations of 8pm – 12am and ad libitum groups significantly increased compared with the 8am - 12noon and 12noon -4pm groups. Dyslipidemia was observed in the ad libitum group when compared with the 8am - 12noon and 12noon - 4pm groups. Conclusion: From this study, 4-hr time restricted feeding has beneficial effects on body weight, blood glucose, lipid profile and leptin concentration. This feeding restriction patterns may be helpful in obesity management and in preventing metabolic diseases development in non obese.


Behaviour ◽  
1966 ◽  
Vol 26 (3-4) ◽  
pp. 351-356 ◽  
Author(s):  
Edward T. Uyeno ◽  
R. Alan Graham

AbstractMale Wistar rats were deprived of food for 3 days and then forced to swim continuously to a criterion of exhaustion. Controls swam after ad libitum feeding. In the first experiment a load equal to 11% of the rat's body weight was attached to the dorsal skin near the tail during the swim. In a second study, two matched groups, treated identically as those in the first study swam without a load in water treated with a wetting agent, "Aerosol O.T." In a third experiment, controls as well as experimentals were deprived of food for three days. The control group, however, was fed for 30 minutes, immediately before the swim. A fourth experiment was conducted in a similar manner as the third, except both groups were deprived 6 hours. In each of the experiments the deprived groups swam significantly longer than the fed groups.


1975 ◽  
Vol 229 (1) ◽  
pp. 107-112 ◽  
Author(s):  
M Digirolamo ◽  
J Esposito

Resting blood flow was measured in isolated, innervated, epigastric fat-pads of 27 male rabbits during growth in the 1st yr of life and found to vary widely in range (7.6-28.1 ml/100 g tissue per min). Definition of adipose tissue composition and of fat-cell size and number made it possible to explain the wide range of flow and to identify two types of relationships between adipose blood flow and tissue constituents. Expressed in the usual manner (ml/100 g tissue per min), adipose blood flow declined with increasing adiposity of the fat depots, and a negative correlation was found between flow and fat-cell volume (r equals -.571, P less than .01). In contrast, when blood flow was expressed on the basis of fat-cell number (ml/108 fat cells/min), a positive and highly significant correlation was found between blood flow per fat cell and fat-cell volume (r equals .842, P less than .001). In the rabbit tissue the relationship of blood flow to fat-cell number and size was more predictable than the usual expression of flow in terms of tissue wet weight. Food deprivation for 18-24 h did not significantly alter these relationships. The results indicate that changes in adipose tissue composition and cellularity, resulting from growth and from accumulation of lipid in enlarging adipocytes, are important determinants of blood flow regulation to adipose tissue.


2003 ◽  
Vol 83 (3) ◽  
pp. 583-592 ◽  
Author(s):  
P. S. Mir ◽  
E. K. Okine ◽  
L. Goonewardene ◽  
M. L. He ◽  
Z. Mir

Two rat feeding experiments were conducted, concurrently, for 48 d, to determine the effects of feeding synthetic food-grade conjugated linoleic acid (CLA) containing 53% cis 9, trans 11 CLA and 44% trans 10, cis 12 CLA or bio-formed CLA as high CLA beef on adipose tissue development. In exp. 1, 30 (10/diet) weaned male Wistar rats (51 ± 0.65 g) were fed, ad libitum, a control diet, control with sufficient added synthetic CLA to achieve CLA concentrations of 1.1% of diet DM or the control, where the soybean oil in the diet was replaced with sunflower oil. In exp. 2, 20 (10/diet) weaned male Wistar rats (52.5 ± 2.5 g) were fed, ad libitum, diets in which freeze dried beef replaced the casein as the protein source. The meat in the two diets was derived either from steers raised without dietary oil or from beef from steers fed oil to increase CLA content by 144% from 3.36 to 8.20 mg g-1 lipid (high CLA beef). At the end of the experiment the rats were humanely sacrificed and the organs, muscles and the retro-peritoneal and inguinal fat pads were retrieved and weighed. A portion of the fat pad was processed for enumeration of adipocytes while a second portion was used for lipid extraction, and fatty acid composition was determined. In both experiments, diets fed to the rats did not affect rate of growth or carcass, muscle and organ (liver, heart and kidney) weights. In exp. 1, dietary synthetic CLA reduced (P < 0.01) the weight of the retro-peritoneal fat pad and this may have been related to a numerical (-9.8%) but non-significant reduction in feed intake. Although fat pad weight in rats fed sunflower oil was similar to that of rats fed the control diet, the adipocyte number was increased (P < 0.05) by 37%. Dietary supplementation with synthetic CLA, increased (P < 0.05) the CLA concentration in lipids from liver, inguinal fat and retroperitoneal fat of rats. In exp. 2, muscle, organ and fat pad weights were similar for the two meat treatments, but adipocyte number in both pads was lower (P< 0.05) in rats fed the high CLA beef by 40%, which may be a response to dietary CLA and/or a lower protein intake. The lipid from liver and fat tissues of rats fed CLA enhanced beef contained a higher (P < 0.05) CLA concentration than tissues from rats fed the control beef. Data suggest that dietary CLA from either synthetic or high CLA beef may decrease lipid storage potential in fat pads. Key words: Rat, adipose, development, conjugated linoleic acid, high CLA beef


2014 ◽  
Vol 58 (4) ◽  
pp. 377-381 ◽  
Author(s):  
Luciana da Conceição Antunes ◽  
Manoela Neves da Jornada ◽  
Jessica Lorenzzi Elkfury ◽  
Kelly Carraro Foletto ◽  
Marcello Casaccia Bertoluci

Objective: The objective of this study was to evaluate the association between insulin-resistance and fasting levels of ghrelin and PYY in Wistar rats. Materials and methods: A total of 25 male Wistar rats, weighing 200-300 g, was included in this study. The animals were maintained in cages with a 12/12h light-dark cycle and fed standard chow and water ad libitum. After 12-h overnight fasting, ghrelin, PYY, insulin and glucose values were determined. Insulin resistance was assessed by means of the HOMA-IR, which was ranked and the median was used as a cut-off value to categorize insulin-resistance. HOMA-IR values equal and above 2.62 were considered insulin-resistant (IR) while values below 2.62 were considered insulin sensitive (IS). Differences between means were determined using the Student t-test. Multiple regression and Pearson’s correlation test were used to evaluate the association between variables. Results: HOMA-IR median IQ range values for IS and IR groups were, respectively, 1.56 (0.89 – 2.16) vs. [4.06 (3.50 – 4.61); p < 0.001]. The IR group presented increased levels of fasting ghrelin, PYY and insulin respectively: [50.35 (25.99 – 74.71) pg/mL vs. 12.33 (8.77 – 15.89) pg/mL; p = 0.001]; [54.38 (37.50 – 71.26) pg/mL vs. 33.17 (22.34 – 43.99) pg/mL; p = 0.016]; [18.04 (14.48 – 21.60) uU/mL vs. 7.09 (4.83 – 9.35) uU/mL; p = 0.001]. Ghrelin, but not PYY, correlated linearly and positively with HOMA-IR: ghrelin vs. HOMA-IR (r = 0.52; p = 0.008), and PYY vs. HOMA-IR (r = 0.22; p = 0.200). This correlation was independent of body weight. Conclusion: Fasting ghrelin and PYY serum levels are increased in lean, relatively insulin resistant Wistar rats, and this increase is independent of weight.


1993 ◽  
Vol 71 (3-4) ◽  
pp. 234-240 ◽  
Author(s):  
R. Savard ◽  
M. R. C. Greenwood

The response to energy intake and expenditure is thought to be influenced by the genetic background. In the present study the metabolic response to pregnancy and to exercise training during pregnancy was investigated in two strains of rats. Lean Zucker and Wistar rats were divided into three groups: control pregnant (CP), exercise-trained pregnant (TRP), and not trained and not pregnant control (CNP). Trained rats swam 3 h per day, 6 days per week, throughout pregnancy. Body weight and food intake increased similarly during pregnancy in both strains (p ≤ 0.05). However, only Wistar rats had a further increase of food intake and body weight during the second half of pregnancy: TRP weighed 29.1 more grams and ate 4.5 more grams of food per day than CP at the end of pregnancy (p ≤ 0.05). Inguinal and parametrial fat cell sizes were unchanged during pregnancy. In both strains training induced a decrease of inguinal fat cell size at the beginning of pregnancy (p ≤ 0.05), which was rapidly counteracted to reach CP values on day 20 of pregnancy. Parametrial fat cell size was also decreased by training (p ≤ 0.05), but no values returned to control levels during pregnancy. In both strains, pregnancy increased fat cell lipolysis in the inguinal depot only (p ≤ 0.05). Training during pregnancy inhibited fat cell lipolysis in inguinal and parametrial depots, especially in Zucker (p ≤ 0.05), TRP reaching values similar to control values on day 20 of pregnancy. These results suggest that the effects of exercise training on the morphology of adipose tissue are similar in different strains of rats. They also show that the mobilization of fatty acids during pregnancy could respond to training in a strain-specific manner.Key words: adipose tissue, lipolysis, rat strain differences, pregnancy.


2017 ◽  
Vol 68 (7) ◽  
pp. 1481-1484 ◽  
Author(s):  
Radu Mihail Mirica ◽  
Mihai Ionescu ◽  
Alexandra Mirica ◽  
Octav Ginghina ◽  
Razvan Iosifescu ◽  
...  

Obesity involves the growth of adipose tissue cells (adipocytes and preadipocytes), as well as microvascular endothelial cells. Matrix metalloproteinases (MMPs) are relevant ezymes for the modulation of extracellular matrix (ECM) and adipocyte and preadipocytes differentiation. They are elevated in obese patients, generating abnormal ECM metabolism.[1]. This article proposes a thorough study of literature with focus on the important roles of matrix metalloproteinases in the pathophysiology of obesity. The article represents a narrative review based on an English-language PubMed research of the medical literature regardind important aspects of the proposed aim. MMP-2 activity was signi�cantly higher than MMP-9, both activities were detectable. MMP-9 was strongly correlated with body weight parameters before surgery, as well as after significant body weight reduction as a result of bariatric surgery. Concerning MMP-2 and MMP-9 they are also involved in the turnover of basement membranes both those of adipose tissue and endothelial. MMP-9 levels were moderately correlated with HDL cholesterol levels. Taken together, the present data suggest that changes in ECM through MMP-mediated degradation might play a critical role in the adipocyte differentiation process. These findings are detected both in clinical trials and in laboratory animal experiments. It is then tempting to speculate that the adipocyte-derived MMPs might represent a new pharmacological target for the inhibition of adipose tissue growth by inhibiting adipose differentiation as well as angiogenic process.


2020 ◽  
Vol 20 (07) ◽  
pp. 16984-16996
Author(s):  
MMC Anyakudo ◽  
◽  
DO Adeniji ◽  

The metabolic response to nutrient ingestion and the rate of digestion and absorption of nutrient molecules in bowel physiology plays an important role in the metabolic control of some human chronic non-infectious diseases. This experimentally-controlled designed nutritional study which lasted eight weeks aimed to determine the effects of proportional high-protein/low-carbohydrate (HP/LC) formulated diet on glycemic tolerance, glycemic control, body weight, organ weight and organ morphometry in healthy and diabetic adult male Wistar rats. Twenty-four male Wistar rats purchased from a disease-free stock were randomly categorized into four groups (n = 6, each) after two weeks acclimatization period in raised stainless steel cages with 6 mm2mesh floor and replaceable numbered blotters papers placed under each cage in a well-ventilated animal house. Animal groups include: Healthy control group (HC), Healthy treated group (HT), Diabetic control group (DC) and Diabetic treated group (DT. The animals were fed according to the experimental design with water ad libitumfor eight weeks. Diabetes was inducted with freshly prepared alloxan monohydrate solution (150 mg/kg bw, intraperitoneally). Body weights and fasting blood sugar concentrations were measured twice weekly, while oral glucose tolerance test was conducted on the last day of the eighth-week study and subsequently followed by organs extraction after anesthesia for weight and gross assessment. Proportional high-protein/low-carbohydrate formulated diet caused significant reduction in mean body weight of treated diabetic (DT: 22.6%; P= .001) and healthy (HT: 5.8%; P= .007) rats while the control animals on control diet recorded significant (P< .05) increase in body weight gain (DC: 12.4%; HC: 11.2%). Glycemic tolerance and control improved significantly in diabetic treated rats over that of the healthy treated rats. Gross morphometry of the extracted organs (kidneys, liver, heart, lungs, spleen and testes) revealed sustained normal morphological features without any visible lesion. In conclusion, consumption of proportional high-protein/low-carbohydrate formulated diet enhanced body weight reduction and sustained normal organ morphological features with good glycemic tolerance and control in experimental rats, suggesting its dietary potentiality, safety and suitability to ameliorate obesity-related diabetes.


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