The Influence Of The Combination Of Niacin And Statins On The Vulnerability Of Experimental Atherosclerotic

Objective: The atheromatous plaque will evoke the form of thrombi, which is the main reason of causing coronary heart disease and ischemic stroke. With the rapid development of angiography and related intervening therapy in recent years, people found that above half of acute myocardial infarction are because the stenosis of lumen diameter is less than 50%, and the key factor, which determines whether the patient is liable to turn up the accident of acute thrombus, is the stability of the atheromatous plaque, not the size of the atheromatous plaque. This kind of plaque is called"vulnerable plague". Large amounts of clinical and fundamental experiments have proved that statins have a good effect on the stability of plaque. This stability not only relies on the effect of lipid-lowering drugs on lowering cholesterol levels, and meanwhile statins have the effect on anti-inflammation reaction, changing the organization of vulnerable plague, etc. This so-called"non-reducing lipid"also plays an important role in the stability of plaque. However, statins influence a little on other blood lipids except for cholesterol, and have a worse effect on patients of HLP. Niacin belongs to Class B vitamin, which in the body can rapidly change into nicotinamide that combines with ribose adenine then to form nicotinamide adenine dinucleotide(NAD) and NADPH. Niacin can lower the content of triacylglycerol(TG) in the serum, restraint the liver to synthesize LDL-C, maintain the structural and functional integrity of HDL-C, and increase the level of LDL-C in plasma. According to the above features, the combination of niacin and statins theoretically can make the vulnerable plague more stable. This dissertation uses the rabbits'atheromatous plaque as research object, intervenes them with niacin and statins, explores the effect of niacin and statins on the pathological organization of the atheromatous plaque, and at last compares the effect that is only used statins. This paper discusses whether niacin can improve the vulnerability of atheromatous plaque, and then provide theoretical basis for treating atherosclerosis in clinical patients.Methods: Divide 24 male white rabbits of New Zealand into four groups randomly. Group A is normal control, which is given normal feedstuffs. Group B is model group, which is given hypercholesterol feedstuffs. Meanwhile the abdominal aorta will be overstretched, and the model of atherosclerosis will be made. Group C is simvastatin intervention, which is fed with hypercholesterol feedstuffs, produced the model of atherosclerosis and is given simvastatin. Group D is simvastatin and niacin intervention , which is fed with hypercholesterol feedstuffs, produced the model of atherosclerosis and is given simvastatin and niacin. Group A and B are received equivalent normal saline. The rabbits are put to death after 12 weeks, dissected the specimen of the abdominal aorta plaque, carried out the tissue coloration, and then the plaque fibrous cap thickness and the ratio between the plaque fibrous cap thickness and the thickness of lipid core cross section are measured. TC, TG, LDL-C, HDL-C should be detected both before and after giving the groups medicine. At last, each group analyzes the variance of corresponding data.Results: 1.The results of serology detection: before finishing the experiment, the rabbits have been fed with hypercholesterol feedstuffs for 12 weeks, and Group C and D have been given medicine intervention at the same time. The serology detection shows that there is no significant difference in TG among all groups. Between Group C and D, there is no significant difference in TG(Pï¹¥0.05) and LDL-C(Pï¹¥0.05), but there is significant difference between these two groups and group B (Pï¹¥0.05). There is no significant difference in HDL-C(Pï¹¥0.05)between group B and D, and there is significant difference in HDL-C(P<0.01)between these two groups and group C.2.The features of plaque histology. After vertically opening the rabbit's abdominal aorta, we can see the obvious distribution of continuous atheromatous plaque below the diaphragm level. Taking specimens stained with HE, We can find ,under the microscope, the plaque fibrous cap in plaque model is thinner; the lipid core is relatively larger. While the plaque fibrous cap in intervention group is thicker; the lipid core is relatively smaller. We use image collection system to collect the image, and to measure the thickness of plaque fibrous cap and the ratio between each plaque fibrous cap thickness and the thickness of lipid core cross section. Each plaque is taken at least 10 places to measure and then to get the average. The places include both thickest and thinnest.3. The statistical analysis. The analysis of variance shows that there is significant difference in the thickness of plaque fibrous cap, the lipid core cross section, and the ratio between them between the model group (group B) and simvastatin and niacin intervention (group D) (P<0.01). There is no significant difference in the thickness of plaque fibrous cap and the thickness of lipid core cross section, but there is significant difference in the ratio between them (P<0.05).Conclusion: This research shows that the vulnerability of plaque is related to its organization features, niacin and statins are used together to lower the blood lipid reasonably and fully, and then the organization of the plaque can be improved, the development of the plaque can be prohibited, and the atheromatous Plaque can become more stable.