The Study Of Hyperlipemia And Atherosclerosis Model In The Rabbits Fed An Atherogenic Diet

Coronary heart disease(CHD) affects human healthy seriously, and its incidence rate and death rate are much higher in cardiovascular diseases. At present, it has already become a detriment to human life. Atherosclerosis (AS) is the basic pathological processes of CHD. Therefore, it is important to set up an AS animal model similar to the disease in human. Many investigators have used high fat diet to induce AS in animals. But Clifton et al. found that there was a difference amony individuals who responded to changes in dietary fat and in cholesterol. Previous experiments indicated that the building of AS model in rabbits need long time. So far, it is not clear the individual variations responsible for development of hyperlipemia and atherosclerosis in the rabbits fed a high fat diet. In the precent study, we established a hyperlipemia and AS model using rabbit fed an atherogenic diet, and observed morphological changes in blood vessels.Aim: To establish a hyperlipemia and AS animal model in the rabbit fed an atherogenic diet, and observed morphological changes in blood vessels.Methods: Ten rabbits were selected from 80 New Zealand white male rabbits and fed a normal diet, the rest rabbits were fed an atherogenic diet. At the end of the 4th week, 22 rabbits fed an atherogenic diet were dead. At the end of the 4th week, blood samples of 48 rabbits fed an atherogenic diet were taken. Eight rabbits in whom the serum cholesterol level was less than 10 mmol?L-1 were divided in diet-insensitive group, and the serum cholesterol level of others exceeded 10 mmol?L-1. Ten animals were select randonly from the 40 rabbits diet-sensitive group. At the end of the 13th week, rabbits were anesthetized with an intravenous injection of pentobarbital sodium (25mg?kg-1, iv). Then, the blood samples and aorta were taken.Results:1 Changes in body on the weight in the sensitive or insensitive to atherogenic diet rabbits.Before and after giving an atherogenic diet, there were no significant differences in body weight of rabbits among 3 groups (P>0.05).Compared with the beginning of the experiment, body weight in the normal diet group, diet-sensitive group and the diet-insensitive group were increased significantly (P<0.05, P<0.01).2 Survival rates of the rabbits fed an atherogenic diet for 13 weeks.The death rates in normal diet group and diet-insensitive group were lower than that in diet-sensitive group, but the difference was not statistically significant (P>0.05). 3 Serum lipid levels in the rabbits fed an atherogenic diet.Before giving an atherogenic diet, there was no difference in the level of serum total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C) among the 3 groups (P>0.05).After giving an atherogenic diet, the levels of serum TC, TG, HDL-C and LDL-C in the diet-sensitive group were significantly increased in comparison with the beginning of the experiments (P<0.01). From the 7th week to the 13th week, the levels of serum TC, HDL-C and LDL-C in the diet-insensitive group were increased significantly (P<0.01). The level of serum TG in the diet-insensitive group was differently in normal diet group (P<0.01).4 Morphological changes in the aortic arch, thoracic aorta and abdominal aorta of the rabbits fed an atherogenic diet.Observed by macroscopic observation, the vessel wall in aortic arch, thoracic aorta and abdominal aorta of rabbits fed a normal diet were smooth and glossy. While, the diet- sensitive and diet-insensitive groups were rough in the vessel wall, and formed AS plaque mix together.Observed by light microscope, there was no AS plaque formed in the vessel wall of the aortic arch, thoracic aorta and abdominal aorta of rabbits fed a normal diet. The diet-sensitive group and the diet-insensitive group had rough and thick inner membrane, and contained a great quantity foam cells. 5 Morphological changes in the femoral artery and common carotid artery of the rabbits fed an atherogenic diet.Observed by macroscopic observation, the vessel wall in femoral artery and common carotid artery of rabbits fed a normal diet were smooth and glossy. The diet-sensitive group was rough in the vessel wall, and formed few AS plaque. The diet-insensitive group was smooth in the vessel wall, but the elasticcity of vessel wall was weaker slightly than that of the normal vessel wall.Observed by light microscope, endothelial cell lined up in order, there was no foam cell and lipids formed in the inner membrane and tunica media of the femoral artery or the common carotid in the normal diet group. The diet- sensitive group and the diet-insensitive group had a few fibrous plaques.Conclusion: We built the hyperlipemia and AS model in the rabbits fed an atherogenic diet. The rabbits had differ- ence on the sensitivity of the atherogenic diet. Then, it was divided into diet-sensitive group and diet-insensitive group according to the difference on the sensitivity of the atherogenic diet. The disease resistance and the adaptability of the environment in the diet-insensitive group were higher than that in the diet-sensitive group. Compared with the diet-insensitive group, the survivability of the diet-sensitive group was stronger. The level of serum TC, TG, HDL-C and LDL-C in the diet-insensitive group were increasing slowly. Although had difference on the sensitivity of the atherogenic diet, the vessels all formed AS. The degree of the AS was different. The research indicated that AS formed in big vessels were easier and more severity than in small vessels.