Induce Hyperlipidemia in Rats Using High Fat Diet Investigating Blood Lipid and Histopathology

Abstract

Induce Hyperlipidemia in Rats Using High Fat Diet Investigating Blood Lipid and Histopathology. J Hematol Blood Disord 4(1):104 The experiment was conducted to investigate the effect of induced hyperlipidemia in SD rats fed with high fat diet (HFD) for 7 weeks on blood lipid profile and possible pathological changes in liver, stomach, intestine, heart, spleen, lung and kidney. There were significant differences in most rats which induced hyperlipidemia throughout the experimental period with the blood lipid levels and histopathology. Abstract

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Case Report Open Access
Volume 4 | Issue 1
Induce Hyperlipidemia in Rats Using High Fat Diet Investigating Blood Lipid
and Histopathology
Karam I*1, Ma N2, Yang Y-J2 and Li J-Y2
1Central Laboratory of Veterinary Research, Soba (Animal Resources Research Corporation ARRC) Sudan
2Key Lab of New Animal Drug Project of Gansu Province; Key Lab of Veterinary Pharmaceutical
Development, Ministry of Agriculture; Lanzhou Institute of Husbandry and Pharmaceutical Science of
CAAS, Lanzhou, P.R. China
*Corresponding author: Karam I, Central Laboratory of Veterinary Research, Soba (Animal Resources
Research Corporation ARRC) Sudan, Tel: 00249-912-624503, E-mail: isamkarm@yahoo.com
Citation: Karam I, Ma N, Yang Y-J, Li J-Y (2018) Induce Hyperlipidemia in Rats Using High Fat Diet
Investigating Blood Lipid and Histopathology. J Hematol Blood Disord 4(1):104
e experiment was conducted to investigate the eect of induced hyperlipidemia in SD rats fed with high fat diet (HFD) for 7
weeks on blood lipid prole and possible pathological changes in liver, stomach, intestine, heart, spleen, lung and kidney. ere were
signicant dierences in most rats which induced hyperlipidemia throughout the experimental period with the blood lipid levels and
histopathology.
Abstract
Keywords: Rats; Hyperlipidemia; High Fat Diet; Histopathology
Volume 4 | Issue 1
Journal of Hematology and Blood Disorders
ISSN: 2455-7641
Introduction
Hyperlipidemia is modiable risk factor for atherosclerosis and related cardiovascular diseases, including coronary heart disease,
cerebral stroke, myocardial infarction and renal failure are becoming a major health problem in the world recently [1].
Lipids are water insoluble organic compounds, which are essential for many normal functions of living organisms: they are
important components of cell membranes, they are used to store energy, and they play a signicant role as enzyme co-factors,
hormones, and intracellular messengers [6]. Of the many groups of lipids, three are most important from a clinical perspective:
fatty acids, sterols (mainly cholesterol), and acylglycerols (mainly triglycerides) [6,7].
Hyperlipidemia is a heterogeneous group of disorders characterized by an excess of lipids in the blood stream, the term
hyperlipidemia refers to increased concentrations of lipids (triglycerides, cholesterol, or both) in the blood [2-4]. ese lipids
include cholesterol, cholesterol esters, phospholipids, and triglycerides.
e term hyperlipoproteinemia refers to increased blood concentrations of lipoproteins, but it is oen used interchangeably with the
term hyperlipidemia. However, the term hyperlipoproteinemia should ideally be used only in cases where measurement of actual
lipoproteins has been performed [4,5]. Lipids are transported in the blood as large lipoproteins, increased blood concentrations
of triglycerides are referred to as hypertriglyceridemia, while increased blood concentrations of cholesterol are referred to as
hypercholesterolemia.
Four main classes of lipids can be recognized from a metabolic stand point. ese are free fatty acids, triacylglycerol, phospholipids,
and cholesterol and its esters. e principle functions of lipids are to act as energy stores and to serve as important structural
component of cells. To fulll these functions, lipids have to be transported in plasma from one tissue to another, from the intestine
or the liver to other tissues such as muscular or adipose tissue, or from the other tissues to the liver.
Fatty acids are relatively simple lipids and are also important components of many other lipids [6,7]. Cholesterol is the main sterol
in animal tissues.
Dietary intake is the major source of cholesterol, but it can also be synthesized endogenously by the liver and other tissues. It plays
a fundamental role in central metabolic pathways, such as bile acid metabolism and steroid hormone and vitamin D synthesis [6,7].

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Triglycerides are the most common and ecient form of stored energy in mammal .ey can be derived from both dietary sources
and endogenous (hepatic) production [6,7].
Because lipids are water-insoluble molecules, they cannot be transported in aqueous solutions, such as plasma. For that reason,
lipids are transported in plasma as macromolecular complexes known as lipoproteins [2,4,6-10].
Lipoproteins are spherical structures that consist of a hydrophobic core containing lipids (i.e. triglycerides and/or cholesterol
esters), and an amphophilic (i.e. both hydrophobic and hydrophilic) outer layer of phospholipids, free cholesterol, and proteins that
forms a protective envelope surrounding the lipid core [4,6-8,10,11].
Previous works have shown that feeding rats a high fat diet induces hepatic steatosis and liver damage, which are stages of the
disease. us this study was designed to investigate the most histopathological changes which induces by feeding of high amounts
of fats particularly cholesterol on the liver [12,13].
It is worth noting that free fatty acids are transported bound to albumin and do not require incorporation into lipoproteins
for transport [2,4,6,7,9,10]. Plasma lipoproteins dier in their physical and chemical characteristics such as size, density, and
composition. In this study induces hyperlipidemia in rats using dietary intake high fat diet for seven weeks.
Materials and methods
Animals
Twenty Sprague-Dawley (SD) rats SD male rats with clean grade (Certicate No.: SCXK (Gan) 2012-0075), aged 7 weeks and
weighing 120 -130 g, were purchased from the animal breeding facilities of Gansu traditional Chinese medicine University (Lanzhou,
China). ey were housed in plastic Macrolon cages of appropriate size with stainless steel wire cover and chopped bedding. Light/
dark regime was 12/12 h and living temperature is 22 ± 2 oC with relative humidity of 55 ± 10%. Standard compressed rat feed for
group A and the other group B feed by high fat diet aer two weeks of acclimatization, the Male SD rats was fed HFD (41.5% lipids,
40.2% carbohydrates, and 18.3% proteins (kcal)). Weight, food intake, blood lipid parameters were measured during a 7weeks diet
course. Free access to either a standard rodent chow (12.3% lipids, 63.3% carbohydrates,and 24.4% proteins (kcal)), or a high-fat
diet, based on lard, swine oil, (derived from cod liver, HF-F).e food was supplied from Keao Xieli Co., Ltd (Beijing, China).
e study was performed in compliance with the Guidelines for the care and use of laboratory animals as described in the US
National Institutes of Health. Animals were allowed a 2-week quarantine and acclimation period prior to start of the study.
Feeding
e rats were feeding with standard diet for two weeks before starting the experiment as acclimatization period for adaptation,
then for group A as blank group continue for seven weeks as experimental period, for B group feeding with high fat diet for seven
weeks.
Study design
Aer the administration period the rats divided in two in each group ten rats, blood lipids levels were measured, the examinations
were carried out at the end of feeding administration; aer the rats were feed with HFD food, the blood samples were collected
from the rat tail, the rats will be fasting for 10-12 hours before collected blood samples. e serums were got through centrifuge
for 15mins at the speed of 4000g and stored at -20 oC till needed for lipid determination. e blood lipids level including TG, TC,
HDL and LDL were measured on week 7 to make sure the success of hyperlipidemia animal model. Examinations of serum total
lipids, was carried out at the end of experiment.
Blood sample was analyzed for hyperlipidemia indexes with a hematology using Erba XL-640 analyzer (German) was used to
measure the blood lipid level. Moreover, an automatic biochemistry analyzer was used to examine the serum obtained from the
blood sample for the content of TG, TC, LDL, and HDL.
Histology
Aer xation (and subsequent weighing, vide supra), organs sampled for histological examination were dehydrated and paranized
and embedded according to standard sampling and trimming procedures [14]. Sections of 4µm were stained with hematoxylin
and eosin (HE) in an automated way. Microscopic observations were done by initial unblinded comparison of control and tested
samples. Blind and/or semi-quantitative scoring was applied when changes were detected by the initial inspection.
Statistics
All data are expressed as mean ± standard deviation (SD). e dierences of ratios of indexes were analyzed using Dunette’s test
(SPSS 12.0 soware, USA), and inter-group comparisons were made using the Multivariate of General Linear Model.P-values of
<0.05 were considered statistically signicant.

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No deaths were observed in any group over the administration periods. Compared with the control group, the test group exhibited
no related changes in clinical signs such as external appearance, behavior, mental state, and daily activities. With regard to food
consumption, all rats showed a signicant increase in body weight (Table 1).
Week 7Week 6Week 5We ek 4Week 3Week 2Week 1
375.13355.2326.71305.2283.2259.62216.95Model Group
*the weight per gram unit
Table 1: All rats in the tested groups had increased high body weights during experiment
Results
Observations in animals’ health
Table 1 showed increase in body weight.
e results of blood lipid level tests are given in Table 2. ere was signicant change in blood lipid level indexes which include TC,
TG, LDL and HDL, compared with control group there was increase in TC, TG and LDL, while HDL was decrease.
Blood lipid level
TCHLDLHDLTGWeek 7
1.730.3857140.3842861.082143Blank group
2.261139*
0.558319*
0.315255*
1.617488*
Model group
*p< 0.05 signicant dierence from blank group
Table 2: Blood lipid index experimental rats
ere were histopathological changes in organs from the animals in control group and tested group.
Histopathology
Liver cell were also observed there was inltration of lipid (Figure 1). We did not nd any other histopathological changes in any
other organs assessed. e increased liver weights were associated with Centro lobular hypertrophy (Figure 1). In rats, there was a
trend that the rats receiving high fat diet had a higher ratio of fat cells in their livers compared with control. Finally, an increased
ratio of lipid hepatocytes was observed in exposed livers.
Figure 1: High power microphotographs of rat liver show lipid inltration compare control B with tested group A
e results demonstrated that in the kidney lipid happened in the glomerulus of rats and the renal tubule interval of tested groups
following high fat diet administration (Figure 2). No pathological changes such as degeneration and necrosis appeared in renal
tubular epithelial cells in high fat diet groups, while more signicant changes took place in tested groups.
Figure 2: High power microphotographs of rat kidney show lipid inltration compare control A with tested group B

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e stomach, duodenum and ileum showed an increased mucosa height aer high fat diet exposure, this was mainly due to
increased height of the villus (Figure 3).
Figure 3: Low power microphotographs of rat stomach show lipid inltration compare control A with tested group B
e results demonstrated that in the heart lipid happened in the cells (Figure 4) of rats and the muscle interval of tested groups
following high fat diet administration.
Figure 4: High power microphotographs of rat heart show lipid inltration compare control with tested group
Discussion
Hyperlipidemia, a group of metabolic disorders characterized by the elevated levels of lipids, is a major modiable risk factor for
atherosclerosis and cardiovascular disease [5]. ese lipids include cholesterol, cholesterol esters, phospholipids, and triglycerides.
Increased levels of LDL are related to the development of atherosclerosis [15,16].
e result showed that there were signicant increase in hyperlipidemia biomarker which includes TC, TG, LDL and HDL. ere
were histological changes in organs which conrm the previous result of blood lipid. at mean high fat diet successfully induces
hyperlipidemia in rats, to make disease model of hyperlipidemia.
Hyperlipidemia can be the result of an inherited disease in certain breeds of dogs [17]. In pets, hyperlipidemia most oen occurs as
a consequence of some disorder, hyperlipidemia even can also occur spontaneously aer a meal of high-fat diet, particularly table
scraps [9,10]. Hyperlipidemia is seen most commonly in ponies, miniature horses, and donkeys, and less frequently in standard-
size adult horses [18]. In non-ruminants, including primates and man, hyperlipidemia may be increased by dietary manipulations
such as feeding excessive cholesterol or fats with high saturated fatty acid content [19].
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demia rats. Acta Pharmacologica Sinica 35: 1265.
2. Watson T, Barrie J (1993) Lipoprotein metabolism and hyperlipidaemia in the clog and cat: A review. J Small Anim Pract 34: 479-87.
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