Comparisons Of The Expression Of Hsp70between Different Arteries And Its Relationship With Atherosclerosis In Rabbits

Objective:Atherosclerosis (AS) has been a common foundation of many cardiovascular and cerebrovascular diseases. It is widely recognized that AS is a kind of chronic and diffuse disease that affects all vascular beds. However, some vascular beds are not more prone to atherosclerosis than others. Some studies have shown that internal mammary arteries (IMA) plays a negative role in the occurrence and development of atherosclerosis. Compared with coronary artery, IMA has low incidence rate of AS and was used in Coronary Artery Bypass Grafting. Recent researches results reveal that there has the difference of HSP70gene in the human IMA and coronary artery. As a sort of stress protein, heat shock protein70(HSP70) plays a dural part in the progress of AS. So the purpose of this study, through the establishment of AS model by feeding high-fat-diet, compare the gene and protein expression for HSP70in the IMA and coronary artery of the both group, further elucidating that the correlation of HSP70and AS, discussing the difference of different arteries. It brings us an original idea for studying anti-atherosclerosis mechanism of IMA.Methods:In this experiment30New Zealand rabbits were randomly assigned to control group (n=10) and high-fat diet group (n=20). The control group were fed with normal diet.The high-fat diet group were fed with high-cholesterol food (1%cholesterol+5%lard+10%dried egg yolk+84%feed). Twelve weeks later, in part one, AS model should be established. We also observed the morphology of the IMA and coronary artery with the skill of HE staining. In part two, the expression levels of HSP70in IMA and coronary artery tissue were analysed by western blotting, RT-PCR, Real-time PCR and immunohistochemistry skills.The statistical software SPSS17.0was employed to perform comparison and analysis between data in different group.Results:1. At the end of experiment, the control group with ten rabbits and the high-fat diet group with eighteen rabbits were analyzed statistically. In the fourth week, the eighth week and the twelfth week, the blood lipid of rabbits in high-fat diet group rise significantly in comparison with control group (p<0.05).2. In high-fat group, HE stained paraffin section have observed the formation of coronary artery AS plaque. IMA intima was rough without AS plaque. In the control group, the intima of IMA and coronary artery specimens were intact.3. With immunohistochemistry skill, twelve weeks later, the HSP70expression was both observed in high-fat diet group and the control group.4. The IMA and the coronary artery HSP70gene and protein expression of high-fat diet group significantly decreased compared with those expressions in the control group (P<0.05). Compared with the coronary artery, HSP70gene and protein expression of the IMA significantly increased in the control group (P<0.05), however in the high-fat diet group HSP70gene and protein expression of the IMA significantly decreased (P<0.05).Inclusions:1. High-fat diet feeding in the period of12weeks could make coronary artery form AS plaque and induce IMA intima to be rough without AS plaque.2. Compared with the coronary artery, HSP70gene and protein expression of the IMA significantly increased in the control group.however, in the high-fat diet group HSP70gene and protein expression of the IMA significantly decreased. The result suggested that there has the difference in the IMA and the coronary artery. It provides us an original clue to analysis the mechanism of anti-AS.3. The IMA and the coronary artery HSP70gene and protein expression of high-fat diet group significantly decreased compared with those expressions in the control group. The result revealed that HSP70plays a role in the pathogenesis of AS. But the mechanism is unknown. The emphasis of the further study would be in the cellular level.