动物模型,高血脂症 z-bo 2020-08-10 512

　　1 Hyperlipidemia mouse model

　　(1) Replication method Use male KM mice weighing about 35g, in addition to giving them normal feeding conditions, at a dose of 10ml/kg body weight to the mice fat emulsion (preparation of fat emulsion: put 80g lard in In a 500ml beaker and heat it on an electric stove to melt, add 40g of cholesterol and melt it, then add 8g of sodium cholate and 4g of propylthiouracil tablets, stir well, and then add an appropriate amount of distilled water and polysorbate-80( Tween 80), 80ml of 1, 2 propylene glycol, constantly stir, add double distilled water to 400ml and mix well, that is, it is formulated to contain 100g/L cholesterol, 200g/L lard, 20g/L sodium cholate and For a fat emulsion of 10g/L propylthiouracil, store the fat emulsion in a refrigerator at 4°C and use it to melt when used), once a day, for 12 weeks. Twenty-four hours after the last gavage, the eyeballs were removed and blood was taken, and plasma was separated. At the same time, the mice were pathologically dissected, the animal heart, liver, spleen and kidney were taken and weighed, and the organ coefficients were calculated. Measure blood glucose (Glu), total cholesterol (TC), triacylglycerol (TG), high density lipoprotein (HDL), low density lipoprotein (LDL), and uric acid (URIC) in plasma.

　　(2) Model characteristics. After 12 weeks of continuous administration of fat emulsion, the mouse body has obvious fat metabolism disorder, which is manifested by a significant increase in total cholesterol and low-density lipoprotein, and an increase in liver coefficient and spleen coefficient, indicating that the animal has Liver damage and spleen damage occurred. Fat metabolism disorders in the body can lead to steatosis of liver cells, and can further cause fatty liver and even cirrhosis; that is, long-term fat emulsion gavage can cause hyperlipidemia and liver and spleen damage in mice. Using long-term low-dose mouse fat emulsion gavage, the established mouse hyperlipidemia model has a simple modeling method, low cost, uniform modeling conditions, good controllability, and dyslipidemia is closer to clinical classification. Model animals The pathogenesis is similar to that of clinical patients.

　　(3) Comparative medicine In daily life, human hyperlipidemia is usually related to a long-term high-fat diet, and hyperlipidemia is recognized as one of the causes of many diseases such as coronary heart disease, hypertension and diabetes. There are many types of clinical manifestations of hyperlipidemia patients, including simple hyperTCemia with elevated total cholesterol as the main manifestation (may be accompanied by elevated LDL); there are also elevated triglycerides as the main manifestation Simple hypertriglyceridemia (may be accompanied by increased LDL); there are also mixed hyperlipidemia with elevated total cholesterol and triacylglycerol as the main manifestation; and high-density lipoprotein (HDL) reduction as the main manifestation Manifestations of low-high-density lipoproteinemia. At present, there are many human hyperlipidemia animal models. Due to the selection of model animals and the use of different high-fat feed formulations, different hyperlipidemia animal models can usually show different levels of dyslipidemia. For example, the hyperlipidemia model of rats replicated with high-fat diet has mixed hyperlipidemia similar to humans as the main manifestation; and the established golden hamster hyperlipidemia model has TC, TG and HDL. Increased as the main manifestation; and some researchers reported that the rabbit model of hyperlipidemia caused by gavage of homemade fat emulsion showed that TC, TG, and LDL were all increased, while HDL decreased as the main manifestation; some researchers also used feeding The mouse hyperlipidemia model caused by feeding high-fat diet is mainly manifested by simple hyperTCemia with elevated TC. In this method, a small dose of mouse fat emulsion is used to gavage the stomach. The established mouse hyperlipidemia model is mainly characterized by simple hyperTCemia similar to human TC and LDL increase, so it is closer to the clinical dyslipidemia IIa Type of hyperlipidemia. In addition, golden hamsters and guinea pigs have many similarities with humans in terms of lipid metabolism, especially male golden hamsters, which can easily cause arteriosclerosis in a short time when given high cholesterol feed. Therefore, the golden hamster hyperlipidemia model has unique application value in the study of arteriosclerosis. Because HDL in rat serum is the main carrier of blood cholesterol, and the rat itself has the characteristics of fighting atherosclerosis, the study of atherosclerosis caused by hyperlipidemia model is suitable for rabbits and golden hamsters. Feeding rabbits with high-fat diet for a long time can easily develop atherosclerosis. Therefore, the rabbit hyperlipidemia model is often used for atherosclerosis research. However, due to the high ratio of LDL to TC in the serum of healthy rabbits, It is quite different from humans, and attention must be paid when evaluating experimental results. However, large animals such as dogs are difficult to use for rapid research on hyperlipidemia and atherosclerosis due to the long experimental period.

　　2 Hyperlipidemia genetically engineered animal model

　　(1) Replication method In the study of hyperlipidemia model animals, there are wild type, natural defect and genetic modification. Mainly, genetic engineering animal models are made through transgene and gene knockout technology. ①ApoE is a structural protein of CM, VLDL, intermediate density lipoprotein (IDL) and part of HDL. As a ligand, it binds to the HDL receptor and ApoE receptor and mediates the clearance of VLDL, IDL and CM residues. ApoE mutation or lack is often It can cause dyslipidemia and AS, which has attracted widespread attention in the medical community. Studies have used transgenic mice expressing human ApoE2/B to study type III hyperlipoproteinemia (HL P). The DNA of the transgenic mouse is pHEGLL Ecys158, which contains the complete human ApoE2 gene, which is transferred into ICR embryos to breed transgenic mice. ②The method of ApoE*3Leiden transgenic mice is to microinject the target gene ApoE*3Leiden (a variant of ApoE3) into the pronucleus of fertilized eggs produced by mating with the same genetic background (C57BL/6JxCBA/J). The first transgenic mice were mated with C57BL/6J mice to produce a series of transgenic mice. ③After recombining the promoter of the mouse transferrin gene with the protein coding region of the human LDL receptor gene, a mouse carrying this fusion gene was prepared, and the gene was highly expressed in the liver. ④Using gene targeting technology, mice lacking ApoE gene were prepared.

　　(2) Model features

　　1) Transgenic hyperlipidemia animal model The transgenic animals used for blood lipid and AS research are mainly mice. The main reason is that in addition to the genetically clear wild species of mice, there are also a variety of mutant and recombinant species, and the increasingly mature gene mapping technology. ① Human ApoE2/B transgenic mice: This transgenic mouse can highly express ApoE2 in the liver, and then mate with a heterozygous ApoE2 transgenic mouse (ICR) and a heterozygous human ApoB transgenic mouse (C57BL). The offspring have 4 genotypes. Transgenic mice expressing human ApoE2/ApoB are selected. The blood lipid characteristics (VLDL and IDL are significantly increased, while LDL and HDL are decreased) are similar to human HLP. It is a good model for studying the pathogenesis of human HLP. ②ApoE3/Leiden transgenic mice established by Groot et al. This mouse model of hyperlipidemia and AS can be used to study the influence of environmental factors and genetic factors on HLP, and it can also be used to screen blood lipid regulating drugs and anti-AS drugs. This transgenic mouse is highly prone to hyperlipidemia and AS induced by a high-fat diet (even a low-fat diet), and this model has a significant advantage in that it can study the relationship between serum TC exposure and AS area . ③In addition, Yokode et al. used the transferrin gene promoter and the protein coding region of the human LDL receptor gene to study the effect of increased LDL receptor gene expression on the TC level after high-fat diet feeding. After feeding on a high-fat diet for 3 weeks, the plasma TC level in the normal control group increased by an average of 4.8 mmol/L, while in the transgenic mice it only increased by 0.7 mmol/L. The reason is that due to the high expression of LDL receptor protein in transgenic mice, only a small increase in cholesterol in VLDL; while in normal mice, cholesterol in VLDL, IDL and LDL all increase.

　　2) The gene knockout hyperlipidemia animal model lacks the ApoE gene, and the homozygous transgenic mice do not have ApoE in the plasma. Under normal diet, the plasma TC level is 5 times that of the normal control group. The main reason is VLDL , IDL and LDL increased cholesterol content, while HDL-C decreased by 55%. The above-mentioned changes in blood lipids are similar to humans with congenital absence of ApoE. It is a model for researching drugs or gene therapy for hyperlipidemia.

　　(3) Comparative Medicine AS is also an inflammatory disease. Hypercholesterolemia and LDL are one of the most important pathogenic factors, and they play an important role in the pathogenesis. The genetically modified animal model provides a reference for the selection of experimental animal models for hyperlipidemia research, and provides a brand-new experimental system for the study of the relationship between hyperlipidemia and AS. It is of great significance to the research of hyperlipidemia. Transgenic animal models must It will be the development trend of animal models in the future.