Abstract:In present experiment the temporal increase of the calcium level both in cytoplasma and nuclear of single culture endothelial cell was observed after stimulation of tumor necrosis factor-a (TNFa, 1MIU·L-1), however, the increase of calcium level was more significant in nuclear and decreased slowly. The calcium level was not changed obviously in white cell after stimulation of TNFa in same dosage. The calcium level both in endothelial cell and white cell increased rapidly and ten decreased less than the original level alter stimulation of phorbol myristate acetate (3. 5nmol·L-1 ) which is a activator for protein kinase C (PKC). Finally, it was found that the nuclear calcium of endothelial cell was output entirely, but there was calcium reside in the n[lclear of white cell. The results suggested that the effects of TNFa stimulation are different on the different kinds of target cells. the changes of calcium level are different in different region of cell,and the PKC plays an important role in the calcium output from inside of the cell.but it may don't participate in the offect of TNFa on the cell calcium. Investigating the calcium change in the single endothelinalcell should benefit the research on the role of Ca²⁺ in the pathogenesis of atherosclerosis.

Abstract:The effects of endothelin-1 on DNA synthesis and expression of genes related to cell proliferation in rat vascular smooth muscle cells (VSMC) were investigated by 3H-TdR incorporation and Northern blot analysis. The results suggest that 3H-TdR uptake increased at 12 h after stimulation with endothelin-1, with reaching a peak at 24 h.Endothelin-1 induced rapidly and transiently the expression of the proto-oncogenes c-fos and c-jun,the activity of their expression peaked at 30 min after stimulation, and rapidly declined there after. The expression of the p34cdc2 kinase gene augmented at 12 h after endothelin-1 stimulation and continuously expressed at relatively high levels until 24 h. These data indicate that endothelin-1 stimulates DNA synthesis of VSMC by inducing the transcription of genes related to cell proliferation.

Abstract:In this study, two monoclonal antibodies (McAb) against malondialdehyde-modified low density lipoprotein (MDA-LDL) were obtained, designated as HML1 and HML2 respectively, both of them can react to MDA-LDL with a high titer and belong to the subclass of IgG2a. The McAb additivity test shown that two McAb were against the same determinants of MDA-LDL. Solid-phase competitive biotinavidin EIA indicated that HML1 recognized MDALDL, MDA-alburnin, MDA-polylysine but not native LDL.It is postulated that the covalent aducts of MDA with lysine residues are involved the formation of MDA-derived epitopes on apolipoprotein B.

Abstract:To explain the relationship between low density lipoprotein(LDL) and local anticoagulation in the atherosclerotic pathogenesis, the effect of varied LDL concentration with different incubation time on the activation of protein C by thrombomodulin (TM) of the surface of cultured newborn bovine aortic endothelial cells was investigated. After incubation, thrombin, protein C, and S-2238 were used for measuring TM-dependent protein C activation. The results showed a significant decline of TM activity after incubation with over 6 mg·L-1 of LDL and a significantly negative correlation between the LDL concentration and TM activity (y=-0. 25x + 65.96, r=-0. 87, n= 175, p<0. 001 ). The longer the incubation time with more than 50 mg·L-1 of LDL was taken, the more significant inhibition of TM activity would be shown. Reaction rate of activated protein C generation was decreased in early, and increased later.These data suggest that elevated blood levels of LDL may contribute to the atherosclerotic pathogenesis by decreasig function of local anticoagulation.

Abstract:To investigate the relationship between the quantitative morphometric characteristics of intimal thickening and coronary atherosclerosis, 306 coronary arteries from 102 autopsied cases, 61 males and 41 females.aged 15 to 39 years (divided into 5 age groups), in Beijing were morphometrically studied.Methods By using an image analysis system, intimal and medial thickness was measured,intimal to medial thickness ratio, eccentricity index, luminal stenosis rate. and average annual increasing rate in intimal thickness were calculated.Results The intimal thickness increased with ageing.The intima was markedly thicker in males than in females of the same age group. Among the 3 coronary arteries[left anterior descending (LAD),right coronary (RC) .and left circumalex(LC) ]studied, the rate and degree of intimal thickening were most marked in the LAD and then the RC and LC. Intimal thickening increased more rapidly in the LAD in both sexes in the 20 ～24 years group with average annual increasing rates of 8. 6 % (males) and 9. 5% (females). The thickness then remained steady. However, a second peak of thickening of the LAD in the 35～39 years group in males with a average annual increasing rate of 9. 2% ,meanwhile the percentage of luminal stenosis was 57.4%. The average annual increasing rate of LAD was up to 3. 8% in females in the 30 to 34 y6ars group with no further increase in the 35～39 years group,but the percentage of luminal stenosis was <51 %. Two different types of thickening,namely diffused and eccentric,were found, the latter with characteristic features of atherosclerosis is prone to develop into atherosclerosis plague. The type of thickening of LAD which shows the highest prevalence of CHD clinically was eccentric.Conclusions Intimal thickening with ageing is a changing from physiological to pathological process and intimal thickening froms the structural base for atherosclerosis.

Abstract:The atherosclerotic prevalence and characteristic of atherosclerotic lesion were investigated in the .coronary arteries from 100 subjects who died from accidents and aged 15～30. The results were as follows:Some fatty streak was possibly to transfer into plaque through intermediated lesion. Atherosclerotic plaques of the youn were characterized with proliferative cellular fibrous tissues. The overall prevalence of coronary atherosclerosis was 56. 0% which was higher in males than in females and it also showed increasing tendency with increasing age. The prevalence of coronary stenosis had positive correlation with the prevalence of plaque. The study demonstrated a higher atherosclerotic prevalence, especially the higher prevalence of coronary stenosis,in the young subjects in Beijing,suggesting the prevention and cure of atherosclerosis be emphasized in youth.

Abstract:Chondroitin sulfate proteoglycan (CSPG) was analyzed quantitatively on the basis of immunohistochemistry in 19 coronary arteries from district of high prevalence of atherosclerosis (Beijing)and 13 coronary arteries from district of low prevalence of atherosclerosis (Ningbo) with image analyzer,and the coronary arteries of one heart were chosen for immunoelectron microscopy. The results were as follow: ①The network-like CSPG positive substances were distributed diffusely in extracellular matrix (ECM): CSPG content was higher in intima than in medial ②The more colloidal gold particles were distributed in the loose region of ECM and the less on the surface of collagenl;③CSPG content in coronary arteries was higher in Beijing than in Ningbo. Suggesting that difference of CSPG content in coronary artery is likely related to diversity of coronary morbidity betWeen districts of atherosclerosis high and low prevalence.

Abstract:By means of cell counting and MTT assay, we observed that cultured bovine aortic smooth muscle cells (SMC) incubated with oxidized low density lipoprotein (OLDL, 0. 2 g protein·L-1 )for 12 hours and xanthine (X, 100 μmol·L-1) plus xanthine oxidase(XO, 100 U. L-1 ) for 2 hours showed multiplication of bovine aortic smooth muscle cells and that the effects of OLDL and X-XO were significantly inhibited by probucol. Synthesis inhibitor of nitric oxide (NO) NG-nitro-L-arginine(NG-L-Arg, 100 μmol· L-1) could not abolish the effect of probucol. Our data indicates that probucol could contend with multiplication of SMC induced by OLDL or X-XO.

Abstract:Reductions in nitric oxide (NO)activity persist after arterial intimal injury and may be a factor in the development of atherosclerosis. NO inhibits in vitro or in vivo platelet aggregation,leukocyte adhesion,and smooth muscle cell growth,all of which are key components in the process of intimal hyperplasia. We hypothesised that supplementation with Larginine, the presursor of NO, would increase NO production and thereby improve endothelium-dependent vasorelaxation and inhibit the development of atherosclerosis. Twenty-four New zealand white male rabbits were divided to four groups: ①uninjury, ②unilateral iliac artery injury + 2% cholesterol, ③ LArginine, ④unilateral iliac artery injury + 2% cholesterole 2K L-arginine. The iliac arteries were harvested for functional and morphometric studies. Maximal endothelium-dependent vasorelaxation in group ①,③and ④ was significantly greater than in group ②, but there was no significant difference of endothelium-dependent vasorelaxation among group ①, ③ and ④, L-arginine could partly inhibit the development of atheroselerotic plaques. These data suggest that L-arginine supplementation enhances NO production at sites of vascular healing and may reduce the development of proliferative atherosclerotic lesions.

Abstract:New Zealand white rabbits were divided at random into three groups which were, fed a normal chow (Control ) and a high-cholesterol diet (HCD), a high cholesterol diet suplemented with Larginine(HCD-Arg) for 4 or 8 weeks respectively. In the high-holesterol diet group (vs HCD-Arg group),scanning electron micrographs of rabbit aortic arteries stained with silver nitrate showed that endothelium cells had irregular sizes and lacked the typical alignment in the direction of blood flow. Permeability of endothelium cells of atherosclerotic plaques was increased in HCD group (vs HCD-Arg group). Meanwhile, L-arginine could partly inhibit the development of atherosclerotic plaques. These data suggest that hypercholesterolemia enhances the endothelium lesion ;this effect is affenuated by dietary L-arginine.

Abstract:Endothelial injury and thrombosis are essential events initiating restenosis after ballooning argioplasty. An arterial stenosis model was estabished in New Zealand rabbits by external crushing of the ear central artery. Vascular endo-thelial growth tactor and hirudin were injected subcutaneously in the vicinity of and retorgrade, intra-arterially distal to the crushing sits. The cross-sectional percentage of stenosis, calculated by measuring the areasof the patent lumen and neointima on sections with the most prominent smooth muscle cell hyperplasis, was compared between the study group and control group.No signiticant difference was found (P > 0. 05 ). The faiture of the treatment was discussed.

Abstract:In order to study collagens' change with aging and its relation to atherosclerosis,left anterior descending branches of 26 autopsies, aged 15 to 39 years,died by accidents, such as violence and traffic accidents were collected from Beijing (16), one of the atherosclerosis higher prevalence location. and Ningbo (10), one of the atherosclerosis lower prevalence location. They were stained picrosirius red and observed using polariscope. The results showed that collagens type Ⅰ and Ⅲ atherosclerotic had the trend of increasing with the development of atherosclerosis and also had the trend of increasing with aging in left anterior descending branches, type Ⅰwas in majority and it was more obvious in Beijing than in Ningbo,this may be susceptible to atherosclerosis.

Abstract:Effecfs of vitamin B₆ on experimental atherosclerosis of rabbits induced by high lipid diet were observed. Twenty-four New Zealand white male rabbits were at random divided into three groups: ① dieting a normal feed, ② dieting the deed that contains 1% cholesterol and 1% triglyceride, ③dieting the feed that contains 1% chblesterol and 1%triglyceride and vitamin B₆ for 12 weeks. The result showed that after 8 weeks the concentration triglyceride of plasma total cholesterol and in the experimental group was lower than that in the control group and of significance in statistics (p<0. 01 ). But,the concentration of high density lipoprotein cholesterol was similar in the 2 groups. The atherosclerotic lesion in the experimental group was significant difference from and smaller than that in the control group (75.8 ± 9.0% vs 85. 0±5. 4% ) after 12 weeks. Thus indicating that vitamin B₆ may inhibit the formation and development of atherosclerosis.

Abstract:Oil red O staining and analysis of cell image are used to quantitate and compare the uptake of oxidized low density lipoprotein (OLDL)bymoues peritoneal macrophages under different cultural conditions. The results show that absence of LDL (1640 medium contains 5 percent BSA) and OLDL preincubation enhances the uptake of OLDL by 25 and 105 percent respectively, while high concentration of LDL (1640 medium contains 200 mg. L-1 LDL) or 1 g ·L-1 BCG preincubation decrease the uptake by 46percent and 26 percent. No predminant alteration occurs after pretreatment of 100 mg·L-1 SiO2. The results suggest that absence of LDL and OLDL preincubation induce the scavenger receptor activity, while high concentration of LDL or BCG suppress those receptors.

Abstract:Changes of vascular relaxation after balloon denudation of the rabbit aorta were investigated. Endothelium-dependent relaxation of ballooninjured vessels to acetylcholine was reduced significantly, 27. 7±9. 9% and 51. 1± 11. 4% of control at 2and 4 weeks after denudation, respectively. However,sodium nitroiprusside-induced relaxation and noradrenaline-induced contractile remained unchanged in the denuded vessel rings. After balloon denudation,vascular smooth muscle cell proliferation increased,and intima thickened. These findings indicated that function of vascular endothelinm-dependent relaxation was injured, and endothelum-derived relaxing factor production may diminished after balloon denudation.Vascular smooth muscle cell proliferation was related to these changes.

Abstract:To look for the effective method of prevention and treatment for the atherosclerosis (As), we made this experiment with fatty acid sodium of evening primrose oil for observing the effect of the drug to As in morphology.Methods Sixteen rabbits were divided into one experimental and two control group. In the experimental group, 4. 1 g/kg fatty acid sodium of evening primrose oil was given to each rabbit daily for 150 days. Each rabbit of the experimental and the first control group was fed with 0. 5 g cholesterol per day. After 150 days of feeding, all the rabbits were killed by air embolism. Aorta was investigated by optics and electron microscopy.Results The result indicates that As lesions were significantly improved in experimental group than in control one.Conclusion Our study indicats that fatty acid sodium of evening primrose oil shows remarkable preventive effects on experimental As in rabbits.