Preliminary Study On Preparation Of Atherosclerosis Model Using Guangxi Bama Mini-Pig

Atherosclerosis(AS), the basis of the pathogenesis of cardiovascular disease, is a kind of arterial disease caused by heredity and environment. Its main features are the intimal-thickening, the narrowing of lumen, the rupture of unstable fibrous cap and the formation of acute thrombosis. Its pathogenic mechanism is not very clear, therefore, it is of vital importance to establish animal models to research the mechanism of its generation and development. Miniature pigs are similar to human in anatomy, physiology, blood chemical indexes, the mechanism of pathogenesis and so on, consequently, they are used to build animal models of cerebrovascular diseases and diabetes mellitus. In this study,10diabetes mellitus pigs were selected as experimental group1, and10pigs of three months and10pigs of six months in age fed with conventional diet were respectively selected as group2and experiment group3. Meanwhile,10pigs of six months in age were selected as control. Pigs from groups1,2and3were fed with diet containing high fat and high cholesterol, and those from control group were fed with the normal diet.There were the occurrences of hypercholesterolemia and the increases of atherosclerosis index (AI>4.0) in pigs from group1which were fed with high fat and high cholesterol diet for three months. In addition, the results of vascular slices showed the different levels of damages of vascular intima, obvious intimal thickening of abdominal aorta and arteria coronaria, the swelling of fibrous plaques and the narrowing of lumen. Meanwhile, it had been observed that there were smooth muscle cells arranged in loose disorder, a lot of inflammatory cells and foam cells, the typical crystallization of cholesterol and calcification of the bottom of the plaque and the level V of pathology in the lesion through HE staining examination.The weight of pigs in group2and group3obviously increased after fed with high fat and high cholesterol diet. Four animals from group2had a AI value of more than3.8which lasted for3months after fed with high fat and high cholesterol diet for5months. Two pigs from group3showed a AI value of more than3.8lasting for3months after fed with high fat and high cholesterol diet for2to3months. In the vascular tissue section of pigs from group3fed diet with high fat and high cholesterol content for3months or6months, there were the damages of vascular intima, the obviously swelling of fibrous plaque, the disorderly medial smooth muscle cells, the scattered inflammatory cells and foam cells, the crystallization and unconspicuous calcification of cholesterol and the level Ⅱ or Ⅲ of fibrosis lesion through HE staining examination. It was preliminarily determined that pigs showed AS should has a AI above3.8which lasted for3or more than3months through the relative analysis between pathogenic results from the tissue section study and the AI. In accordance with the standard, the percentage of incidence of AS pigs in group1,2and3were100%,40%and20%at the end of the experiment, respectively.The length (300bp) of coding sequence (CDS) of monocyte chemotactic protein1(MCP-1) of Guangxi BAMA mini-pigs acquired by cloning was completely consistent with the MCP-1sequence of Sus scrofa released in NCBI. The sequence displayed homology (84.4%) to human, rabbit (82.1%) and mice’s (74.2%) MCP-1sequence, respectively. Moreover, the predicted conservative location of cysteine in MCP-1from Guangxi BAMA mini-pigs was in consistency with that from human. Therefore, It was suggested that their secondary structure should be the same or similar.The expressions difference of MCP-1, LOX-1and Matrix metalloproteinases9(MMP-9) between group3and control group were researched. Immunohistochemical analysis results showed that there were strong positive expression of MCP-1, MMP-9and LOX-1in experimental group3, and no or weak expression in the control group. The results of qRT-PCR showed there were the increases of expression of MCP-1in the experimental group3with the increasing of the experimental period. A significant increase (p<0.05) of the expression of MCP-1at the carotid artery was observed in the experimental group3but not in control group, no significant difference of the expression of MMP-9was detected between the experimental group3and control group (p>0.05).