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Temporal and Quantitative Analysis of Atherosclerotic Lesions in Diet-Induced Hypercholesterolemic Rabbits
Qi Yu,Yafeng Li,Ahmed Bilal Waqar,Yanli Wang,Bingqiao Huang,Yulong Chen,Sihai Zhao,Peigang Yang,Jianglin Fan,Enqi Liu
Journal of Biomedicine and Biotechnology , 2012, DOI: 10.1155/2012/506159
Abstract: The diet-induced atherosclerotic rabbit is an ideal model for atherosclerosis study, but temporal changes in atherosclerotic development in hypercholesterolemic rabbits are poorly understood. Japanese white rabbits were fed a high-cholesterol diet to induce sustained hypercholesterolemia, and each group of 10–12 animals was then sacrificed at 6, 12, 16, or 28 weeks. The rabbit aortas were harvested, and the sizes of the gross and intima atherosclerotic lesions were quantified. The cellular component of macrophages (Mφs) and smooth muscle cells (SMCs) in aortic intimal lesions was also quantified by immunohistochemical staining, and the correlation between plasma cholesterol levels and the progress of atherosclerotic lesions was studied. The ultrastructure of the atherosclerotic lesions was observed by transmission electron microscopy (TEM). Widely variable atherosclerotic plaques were found from 6 weeks to 28 weeks, and the lesional progress was closely correlated with cholesterol exposure. Interestingly, a relatively reduced accumulation of Mφ, an increased numbers of SMCs, and a damaged endothelial layer were presented in advanced lesions. Moreover, SMCs were closely correlated with cholesterol exposure and lesional progress for the whole period. Cholesterol exposure directly determines atherosclerotic progress in a rabbit model, and the changes in the cellular component of advanced lesions may affect plaque stability in an atherosclerotic rabbit model.
Hypercholesterolemia Impaired Sperm Functionality in Rabbits  [PDF]
Tania E. Saez Lancellotti,Paola V. Boarelli,Maria A. Monclus,Maria E. Cabrillana,Marisa A. Clementi,Leandro S. Espínola,Jose L. Cid Barría,Amanda E. Vincenti,Analia G. Santi,Miguel W. Fornés
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0013457
Abstract: Hypercholesterolemia represents a high risk factor for frequent diseases and it has also been associated with poor semen quality that may lead to male infertility. The aim of this study was to analyze semen and sperm function in diet-induced hypercholesterolemic rabbits. Twelve adult White New Zealand male rabbits were fed ad libitum a control diet or a diet supplemented with 0.05% cholesterol. Rabbits under cholesterol-enriched diet significantly increased total cholesterol level in the serum. Semen examination revealed a significant reduction in semen volume and sperm motility in hypercholesterolemic rabbits (HCR). Sperm cell morphology was seriously affected, displaying primarily a “folded head”-head fold along the major axe-, and the presence of cytoplasmic droplet on sperm flagellum. Cholesterol was particularly increased in acrosomal region when detected by filipin probe. The rise in cholesterol concentration in sperm cells was determined quantitatively by Gas chromatographic-mass spectrometric analyses. We also found a reduction of protein tyrosine phosphorylation in sperm incubated under capacitating conditions from HCR. Interestingly, the addition of Protein Kinase A pathway activators -dibutyryl-cyclic AMP and iso-butylmethylxanthine- to the medium restored sperm capacitation. Finally, it was also reported a significant decrease in the percentage of reacted sperm in the presence of progesterone. In conclusion, our data showed that diet-induced hypercholesterolemia adversely affects semen quality and sperm motility, capacitation and acrosomal reaction in rabbits; probably due to an increase in cellular cholesterol content that alters membrane related events.
Vascular Dysfunction in Short-Term Hypercholesterolemia despite the Absence of Atherosclerotic Lesions
Alireza Garjani,Yadollah Azarmiy,Arezoo Zakheri,Negar Allaf Akbari
Journal of Cardiovascular and Thoracic Research , 2011,
Abstract: Introduction: The atherosclerotic effect of hypercholesterolemia on the vascular function is well-known. However, limited studies were done on the effect of hypercholesterolemia without atherosclerotic lesion on the vascular compliance. The aim of this study was to investigate the effects of hyperlipidemia induced by cholesterol rich diet on vessel function in isolated rat aorta in the absence of atherosclerotic lesion. Methods: Male wistar rats were randomly divided into 3 groups of 6 animals in each. The rats in normal control group were fed a standard laboratory diet and two other groups were fed a high fat diet for 36 days. A group of high fat fed rats was treated orally with Lovastatin started at day of 16 and continued for last 20 days of the experimental period. At the end of the experiment, inferior vena cava blood was collected to measure the lipid levels and the thoracic aorta was excised and used for isolated vessel preparation and histological study. Results: The results of this study indicated that high-cholesterol diet significantly increased total choles-terol and LDL levels in serum (p<0.001). The increase in the serum levels of cholesterol was associated with a profound reduction of endothelium dependent vasodilatation of the thoracic aorta. However, in histopathological study no atherosclerotic lesion was observed. Short-term treatment by Lovastatin (10 mg/kg/day) produced a significant reduction (p<0.05) in the level of total cholesterol and LDL. The endothelium-dependent vasodilata-tion was improved significantly (P<0.01) by Lovastatin as an anti-hyperlipidemic drug. Conclusion: Hypercholesterolemia is associated with endothelial dysfunction in aorta, despite the absence of atherosclerotic lesions.
Effect of simvastatin on the atherosclerotic plaque stability and the angiogenesis in the atherosclerotic plaque of rabbits
Lu Zhang,YueRong Jiang,Mei Xue,CaiFeng Wu,JingShang Wang,HuiJun Yin
Chinese Science Bulletin , 2009, DOI: 10.1007/s11434-009-0509-4
Abstract: In this study, the effect of simvastatin on the atherosclerotic plaque stability and the angiogenesis in the atherosclerotic plaque of rabbits was observed. Thirty New Zealand rabbits were randomly divided into the normal control group, the model control group and the simvastatin group, 10 in each group. Rabbits in the normal control group were fed with normal forage, while rabbits in the rest two groups were fed with high fat forage. The balloon injury was performed two weeks later to establish an abdominal aortic atherosclerosis model, and then high fat forage was successively fed to them. Meanwhile, simvastatin at the daily dose of 2.5 mg/kg body weight was administered to rabbits in the simvastatin group. After 6 weeks of successive administration, levels of blood lipids were measured after blood sampling, and the serum high sensitivity C-reactive protein (hsCRP) and matrix metalloproteinase-3,-9 (MMP-3,-9) were detected using enzyme-linked immunosorbent assay. The macroscopically pathological indices of the plaque tissue were observed using hematoxylin and eosin (HE) staining of abdominal aorta specimens under a light microscope, and the plaque area (PA), cross-sectional vascular area (CVA) and correcting plaque area (PA/CVA) were determined quantitatively using imaging software. The protein expressions of the vascular endothelial growth factor (VEGF), factor VIII related antigen (FVIIIRAg), MMP-3 and cluster of differentiation antigen 40 ligand (CD40L) in the plaque were detected with the immunohistochemical method. Compared with the model control group, the levels of VEGF, FVIIIRAg, MMP-3, CD40L protein expression and the serum expression levels of hsCRP, MMP-3, MMP-9 in the simvastatin group were significantly reduced (P<0.05, P<0.01). The ratio PA/CVA in the simvastatin group was more significantly reduced when compared with that in the model control group (P<0.01). The levels of serum total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL) were significantly reduced in the simvastatin group when compared with those in the model control group (P<0.05, P<0.01). Simvastatin plays a certain role in stabilizing the atherosclerotic plaque, and inhibiting the angiogenesis in the atherosclerotic plaque may be one of possible mechanisms.
Effect of L- Arginine On Electrocardiographic Changes Induced By Hypercholesterolemia And Isoproterenol In Rabbits  [cached]
Pradeep Kumar,Manish Goyal,J L Agarwal
Indian Pacing and Electrophysiology Journal , 2009,
Abstract: Hypercholesterolemia, a well-known cardiovascular risk factor, is associated with prolonged action potential duration, longer QTc intervals (rate controlled QT interval), suggested that Hypercholesterolemia may have a direct effect on ventricular repolarization. Hypercholesterolemia was induced in rabbits and L-arginine was given orally to animals for sixteen weeks. The isoproterenol was injected in all the animals to produce electrocardiographic changes. ECG was recorded in lead II at start of study, after hypercholesterolemic diet and/ or L-arginine supplementation.It is observed that L-arginine significantly reduced the hypercholesterolemia induced QTc prolongation. Isoproterenol induced increase in QTc intervals were decreased only in normolipidemic animals. No significant changes were observed in QRS complex and heart rate. Our study suggests that L-arginine definitely have effect on repolarization processes of myocardium.
Effects of Curcurma comosa Roxb. on Platelet Aggregation and Atherosclerotic Plaque Development in Hypercholesterolemic Rabbits
P. Ratanachamnong,U. Matsathit,Y. Sanvarinda,P. Piyachaturawat
International Journal of Pharmacology , 2012,
Abstract: Curcuma comosa Roxb. (C. comosa), an indigenous medicinal plant containing phytoestrogens, has been reported to have hypocholesterolemic and anti-inflammatory effects. Hypercholesterolemia and inflammation play crucial roles in the development of atherosclerosis. In the present study we investigated whether the hexane extract of C. comosa inhibits atherosclerotic plaque formation and platelet aggregation in hypercholesterolemic rabbits. Rabbits were fed 0.5% cholesterol (N = 6), 0.5% cholesterol plus 5 mg day-1 of simvastatin (N = 6), 0.5% cholesterol plus 100 mg kg-1 b.wt./day of C. Comosa extract (N = 6) or normal rabbit chow (N = 6) for 12 weeks. Blood samples for cholesterol determination were collected in monthly intervals. At the end of the study period, platelet aggregation ex vivo, endothelium-dependent and -independent vascular function of isolated aortic rings ex vivo and aortic plaques were assessed. Cholesterol feeding to the rabbits for 12 weeks significantly increased plasma lipid profiles, platelet aggregation and impaired endothelium-dependent relaxations to ACh and ADP. Supplement with simvastatin or hexane extract of C. comosa attenuated platelet aggregation, plasma lipid profiles and partly restored endothelium-mediated vascular responses. Both simvastatin and hexane extract of C. comosa also improved aortic intimal thickening by about 76 and 74%, respectively. The results indicate that hexane extract of C. comosa possesses the beneficial effects in hypercholesterolemia in similar manner to simvastatin. The therapeutic potential for the prevention or regression of atherosclerosis should be further investigated.
Dietary Corn Oil Counteracts Casein-Induced Hypercholesterolemia in Rabbits
H.E. Mohamed,A. Alhaidary,A.C. Beynen
Journal of Animal and Veterinary Advances , 2012, DOI: 10.3923/javaa.2010.2085.2088
Abstract: In rabbits fed cholesterol-free, semipurified diets, an increase in the intake of casein raises serum cholesterol concentrations, whereas an increase in the dietary level of corn oil has a cholesterol-lowering effect. The question addressed in this study was whether the casein-induced hypercholesterolemia could be antagonized by a high intake of corn oil. Young growing rabbits were fed cholesterol-free, semipurified diets, containing either a relatively low (13.0 energy %) or high level of casein (21.6 energy %), to which extra corn oil (21.1 instead of 5.3 energy %) was added at the expense of an isoenergetic amount of corn starch and dextrose. An increase in casein level as only dietary variable elevated serum cholesterol, whereas an increase in corn oil caused a lowering. The addition of casein to the diet with low content of corn oil produced a high degree of hypercholesterolemia. However, the addition of casein to the diet with high content of corn oil only caused a relatively small increase in serum cholesterol. It is concluded that a high intake of corn oil negates the casein-induced hypercholesterolemia in rabbits.
Lack of Atherosclerotic Lesion Progression on Severe Hyperlipidemic Rabbits  [PDF]
HAYATI Journal of Biosciences , 2009,
Abstract: In human, coronary heart disease causes by severe pathological atherosclerosis. In this study, we established animal model to study atherosclerosis caused by hyperlipidemia. This study therefore was undertaken to define the effect of increasing atherosclerosis risk factor, include body weight as well as age, cholesterol concentration and dietary fat in rabbit chow, and time of treatment. Male New Zealand White rabbits were divided into 4 groups; Group I and III were consisted of 2 months rabbit were fed with standard rabbit chow. To introduce atherosclerosis, the chow for Group II was contained 0.25% cholesterol and 5% palm oil; whereas the chow for group IV was contained 0.5% cholesterol and 5% coconut oil to induce higher atherosclerotic lesion. Results showed that group II and IV developed hyperlipidemia. However, aortic cholesterol concentration in those groups did not different significantly (P > 0.05). We suggest that low carbohydrate composition in diet, 50% lower compared to the previous researches, was able to increase high-density lipoprotein (HDL) concentration. This study demonstrated the complex interactions between low carbohydrate diet and cholesterol metabolism and the dramatic effects of reducing atherosclerosis risk factor; however, even though hyperlipidemic condition was achieved, total plasma cholesterol HDL ratio was maintained low.
Lipid lowering by hydroalcoholic extracts of Amaranthus Caudatus L. induces regression of rabbits atherosclerotic lesions
Najmeh Kabiri, Sedigheh Asgary, Mahbubeh Setorki
Lipids in Health and Disease , 2011, DOI: 10.1186/1476-511x-10-89
Abstract: Twenty five rabbits were randomly divided into five groups of five each and treated 75 days as follows: Group I: normal diet(ND), Group II: Hypercholesterolemic diet (HCD) for 45 days; Group III: Hypercholesterolemic diet (HCD) for 75 days, Group IV and V: HCD for 45 days and then normal diet and normal diet + A. caudatus(150 mg·kg day) respectively for an additional 30 days(regression period). Blood samples were collected before (0 time) and after 45 days and 75 days of experimental diets for measurement of biochemical factors. The aortas were removed at the end of the study for assessment of atherosclerotic plaques.In regression period dietary use of A. caudatus in group V significantly decreased total cholesterol, LDL-cholesterol, malondialdehyde, C-reactive protein while apolipoproteinA and HDL- cholesterol was significantly increased compared to group IV. The atherosclerotic area was significantly decreased in group V. Whereas, the animals that in regression period received only normal diet showed no regression but rather progression of atherosclerosis.These results thus suggest that hydroalcoholic extracts of A. caudatus can reduce risk factors and cause regression of fatty lesons in aorta.Atherosclerosis is a dynamic and reversible process [1]. In animals fed a cholesterol-rich diet, lowering of plasma cholesterol levels promotes the regression of atherosclerotic lesions [1-3]. Evidence for atherosclerosis regression in humans has also been reported [4-6]. Although plasma lipid lowering is a major driving force, the mechanisms that promote lesion regression and stabilization are not clear [7]. Recent reports indicate that the reversal or regression of lesions can be achieved by aggressive lipid lowering or drug treatment [8,9]. Hypercholesterolemia induces oxidative stress, which is known to have adverse effects on the integrity of cells [10]. Antioxidants and hypolipidemic agents suppress the development of hypercholesterolemic atherosclerosis and induce reg
The effect of maternal hypercholesterolemia on the placenta and fetal arteries in rabbits
Frantz, Elemara;Menezes, Honório Sampaio;Lange, Kellyn Cristine;Abegg, Milena Pacheco;Correa, Cora Albrecht;Zangalli, Leoni;Vieira, Jefferson Luís;Zettler, Cláudio Galeano;
Acta Cirurgica Brasileira , 2012, DOI: 10.1590/S0102-86502012000100002
Abstract: purpose: to investigate the degree of placental permeability in dyslipidemic rabbits and the consequent vascular dysfunction in fetuses of female rabbits with high lipoprotein levels. methods: fifteen adult females new zealand white rabbits were divided into two groups. group 1(n=5) - hypercholesterolemic diet with 0.5% cholesterol, and group 2 (n=10) - control. on day 30, the levels of plasma lipoproteins and triglycerides were analyzed in the mothers, and the presence of collagen was analyzed in the placenta as well as in fetal coronary and aorta. statistical analyses used the student's t and the mann-whitney tests. results: lipoprotein levels were significantly different (p=0.02 to p<0.001) in experimental and control groups. in the hypercholesterolemic group, total cholesterol levels were in average 793mg/dl; triglycerides were in average 257mg/dl; hdl-c was 48mg/dl, and ldl-c was in average 692mg/dl. the amount of collagen per micrometers square (mμ2) in samples from hypercholesterolemic animals was significantly higher than in the control group. conclusions: the study confirmed placental permeability to lipoproteins, shown by increased amounts of collagen in fetal tissues. this alteration results in increased susceptibility to atherosclerosis in adult life, representing a risk factor for the early development of disease, which may appear even in the prenatal period.
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