The Primary Preventional Study Of Grape Seed Proanthocyanidin Extract And Atorvastatin On Rabbits' Atherosclerosis

BackgroundAtherosclerosis is a sort of disease threatening the life and health of the old, and it is the pathological basis of cardiovascular and cerebrovascular diseases. It is the main cause of death in developed countries, as for in developing countries, the incidence and mortality of it are getting higher and higher. So the investigation on the mechanism and the treatment of atherosclerosis is attracting more and more attention. Most studies in vivo and in vitro suggested that the development of atherosclerosis was a complexion, the centre of which was low density lipoprotein cholesterol (LDL-c) depositing on the vascular wall and oxidizing, then inflammation cell congregating, invading and activating, therefore atherosclerosis developed.Grape seed proanthocyanidin extract (GSPE) is a sort of polyphenols extracted from grape seeds and it has potent antioxidant activity, so GSPE might play important role in preventing and curing atherosclerosis. Statins belong to hydroxy methylglutary coenzyme A ( HMG-CoA ) reductase inhibitors, it can inhibit HMG-CoA from converting to mevalonic, consequently decrease the composition of cholesterol distinctly. Several landmark clinical trials have demonstrated the important function of lipid lowering with statins for the primary and secondary prevention of coronary heart disease (CHD). Weobserved the primary preventional effect of GSPE and atorvastatin through producing animal model of atherosclerosis, in order to develop GSPE and atorvastatin to apply in the new field of preventing and curing atherosclerosis, and to probe into the effect of lipids and oxidization in the view of atherosclerosis' pathogen. ObjectiveThe aim of the study was to investigate the anti-atherogenic effect of GSPE and atorvastatin through the animal model of experimental atherosclerosis, and to probe into its possible mechanism.(1) to observe the effect of GSPE and atorvastatin on the serum lipid profile in atherosclerosis rabbits;(2) to measure the effect of GSPE and atorvastatin on the serum peroxidation in atherosclerosis rabbits;(3) to observe the effect of GSPE plus atorvastatin on the serum lipid profile and peroxidation in atherosclerosis rabbits;(4) to observe the effect of GSPE, atorvastatin and GSPE plus atorvastatin on antiatherosclerosis by observing the aorta, heart, and cerebrum samples by optical, microscope, electron microscope separately and Immunohistochemical stain of CD68 and a-actin.Methods(1)Animals and diet: 40 male New Zealand rabbits were randomized into five groups with 8 rabbits in each group. They were individually housed in metal cages in an air-conditioned room. Throughout the experimental period, they were given restricted amount of food(100-120g/head per day) of each diet, with no limit of drinking.The control group (group A) were fed with standard diet for 12 weeks; The cholesterol group (group B) were fed with standard diet containing 1 % cholesterol for 12 weeks;The grape seed proanthocyanidin group (group C) were fed with standarddiet containing 1% cholesterol and 1% grape seed proanthocyanidin for 12 weeks;The atorvastatin group (group D) were fed with standard diet containing 1 % cholesterol and atorvastatin (2.5mg/kg/d) for 12 weeks;The GSPE plus atorvastatin group (group E) were fed with standard diet containing 1% cholesterol and 1% GSPE plus atorvastatin (2.5mg/kg/d) for 12weeks.(2)Samples taking: Blood samples were drawn from ear middle arteries of rabbits just before the experiment and at the fourth, the eighth, and the twelfth weekend of the experiment. All the rabbits were fasted for at least eight hours before the blood was drawn. The blood samples ware analyzed for total cholesterol, triglyceride, high density lipoprotein cholesterol, low density lipoprotein cholesterol and malondialdehyde. At the twelfth weekend, two rabbits were chosen randomly from each group to be sacrificed and aorta, heart and cerebrum of rabbits were excised for the morphological observation and immunohistochemical examination.(3) Measurements: Serum TC, TG, HDL-c and LDL-c were measured enzymatically by automatic facilities. Serum MDA was measured as thiobarbituric-acid-reactive substance(TBARS) by fluorometric assay. Aorta, heart and cerebrum samples were observed through optical microscope and electron microscope separately. Immunohistochemical stain of CD68 and a -actin were used to determine the amount of macrophages and smooth muscle cells in the atherosclerotic lesions of the aortas.(4) Statistical analysis: Results were expressed as means±SD. One-way-anova of SPSS 10.0 software was used to evaluate the differences between the groups.ResultsCompared with the control group and model group: (1) The serum lipid profile did not changed appreciably in the rabbits fed withgrape seed proanthocyanidin (p>0.05); while in the atorvastatin group, the serum lipid profile decreased appreciably (P<0.01) , and there is no reciprocal influence between the two groups.(2) In the GSPE group and atorvastatin group, the serum MDA content were lowered markedly (P < 0.01), especially in the GSPE plus atorvastatin group(P < 0.01) , and there is interaction between the two medications, that one can increase the effect of the other.(3) The extent and severity of atherosclerosis were obviously lighted, and the stability of the atherosclerotic plaque was strengthened by GSPE and atorvastatin. The effect of postponing the progression of atherosclerosis in GSPE plus atorvastatin group was better than the GSPE group and the atorvastatin group.Conclusions1. The impacting of GSPE on rabbit's serum lipid level was not remarkable, but it could obviously reduce animal lipid peroxidation in atherosclerosis rabbits.2. Grape seed proanthocyanidin had the efficacy of postponing the development of atherosclerosis and the efficacy of stabilizing the atherosclerotic plaque, the mechanism of which was that it could scavenge free radicals and inhibit the oxidation of lipoproteins.3. Atorvastatin could obviously decrease the serum level of TC, TG, LDL-c and the serum lipid oxidation, but increase HDL-c.4. Atorvastatin could also delay the progression of atherosclerosis and stabilize the atherosclerotic plaque, the function of which was relative to its effects including moderation serum lipid profile and anti-oxidation > anti-inflammation, etc.5. In the Atorvastatin plus GSPE group, the effect of moderating serum lipid profile was not improved prominently, but the effect of anti-oxidation was boosted up, thus the effect of anti-atherosclerosis was increased. They could not only moderate serum lipid profile but could strengthen the efficacyof anti-oxidization, so they could alleviate the development of atherosclerosis obviously, the effect was prior to GSPE or atorvastatin used singly.