The Effect And Possible Mechanism Of Polygonum Multiflorum Total Glycosides On Atherosclerosis Plaque Stability

Acute Coronary Syndrome (ACS) is a clinical syndrome by acute myocardial ischemia, including acute myocardial infarction(AMI) and unstable angina (UA) and sudden cardiac death.The pathological basis of ACS mainly result from rupture or erosion of a vulnerable coronary atherosclerotic plaque and formation of thrombus. The reason of plaque rupture are complicated, but involve with activity of oxidation low density lipoprotein (OX-LDL) and matrix metalloproteinase9(MMPs).ObjectiveUse apolipoprotein E knockout mice as atherosclerotic model, to investigate the effect of polygonum multiflorum total glycosides(PMTG) on oxidant stress and the expressions of protein in aortic atherosclerotic plaques of ApoE gene-deficient (ApoE-/-) mice, so as to discuss the possible mechanism of PMTG stabilizing atherosclerotic plaque and to research the regulation mechanism of MMP-9, to supply new option with increasing stability of As plaque.MethodsWe use 8 weeks-old apoE-/- mice as research objective with high cholecterol diet feeding 16 weeks. They were randomly divided into four groups:model group, high PMTG dose group, low PMTG dose group, positive control group. Use C57BL/6mice as negative control group.After 16 weeks, we examine the morphology and quality of aorta carotid As plaque. To determine blood lipid, liver function and kidney function with conventional method. Serum nitro oxide (NO), total antioxidation capacity (TAC), malondialdehyde (MDA)were measured by routine biochemical method. Consecutive paraffin slice obtained from the root of mice main artery were histochemically colorated to observe the pathological changes of the atherosclerosis(As);to observe the collagen content of As plaque with Masson staining. To observe the expression of CD68,α-SMA ,MMP-9,NF-κB,TIMP-1 inside of As plaque with immunohistochemical staining method.Result1.Copy As plaque animal modelAfert 16 weeks feeding, the lesions of As were obvious in model of ApoE-/- mice,we can observe clearly punctiform or patching uplift in other ApoE-/- mice groups aorta,they mainly locate from aortic sinus to aortic arch, then locate uplift and abdominal aorta. In negative model group, we have no see As lesion and the intima were smooth.2.to observe IMT and As plaque morphy with UBMWe found that aorta intima of all apoE-/-mice were not smooth, and IMT were thick,but have no significant difference(P>0.05);As plaque could be found in all apoE-/-mice and mainly distribute at ascending aorta .Bulk of them were stable plaque,could observe calcification and acoustic shadow. We found soft plaque in model group and have no see As plaque in negative group.3.to observe Effect on the blood lipid and oxidant stress in ApoE-/- miceComparing with those of the model group, serum NO levels of high PMTG dose group and low dose group were significantly increased(32.89±25.79 vs. 3.50±2.35;28.57±12.60vs. 3.50±2.35, respectively, p<0.01), TAC levels were obviously improved(185.23±51.99 vs. 73.69±38.28;184.54±42.06 vs. 73.69±38.28, respectively, p<0.01), contents of MDA were marked decreased(12.83±2.25 vs. 45.47±5.34,p<0.01;12.63±3.21 vs. 45.47±5.34,p<0.05).There were not only no significant difference in serum TC, TG, HDL-C among treatment groups and model group(p>0.05), but also no obvious difference between treatment groups(p>0.05).4. Effect on the formation of As in ApoE-/- miceFour groups have typical fibrolipid plaques and/or atheromatous plaques. But model group's plaques are advanced plaque, fibrous cap of model group's plaques are thinner and have large lipid core,we can observe large foam cells in fibrous cap and plaque. Low PMTG group and positive group wre As plaque. High PMTG dose group have two fibrous plaque,the others were As plaque. The model group's vessel blood walls were diffusedly thicken. Low PMTG dose group and positive group were As plaque. The plaque of high PMTG dose and positive group have thick fibrous cap and little cholesterol crystal. The plaque areas and lumen areas of every group have no significant difference.( p>0.05).5.observe the colleagen content of As plaque with Masson stainingComparison with mdel group and high PMTG dose group and low PMTG group, we found that colleagen content of model group significantly decrease(P<0.05)and the VSMCs content decrease samely.6. Effect on the protein expression of CD68,α-SMA,NF-κB,MMP-9,TIMP-1 in ApoE-/- mice As plaqueThe SMCs and macrophages had different extent of existence in fibrous cap and lipid cores of atheromatous plaques in three groups.The percent of SMCs in high PMTG dose group and low dose group was significantly higher than that of model group(0.24±0.11 vs. 0.14±0.11;0.23±0.17 vs. 0.14±0.11,respectively, p<0.05), on the contrary, the percent of macrophages was notably lower than that of model group(p<0.01).The MMP-9 expression in High and low PMTG group were significantly decreased compare with model group. (respectively, p<0.05). The NF-κB expression of High and low PMTG group were significantly decreased compare with model group. (respectively, P<0.01;p<0.05). The TIMP-1 expression in High and low PMTG group were significantly increased compare with model group. (respectively, P<0.01).Conclusion1. The PMTG have visible antioxidant effect, it could decrease MDA significantly and increase NO, TAC.2. The PMTG could increase colleagen content of As plaque.3. The PMTG could inhibit the expression of CD68,MMP-9,NF-κB and increase the expression ofα-SMA,TMP-1 on plaque.4. The PMTG could stable the vulnerable As plaque .The mechanism of stabling vulnerable plaque was inhibiting the expression of MMP-9. The regulatory pathway of MMP-9 maybe down-regulate expression of NF-κB, up-regulate expression of TIMP-1.To supply new option with increasing stability of As plaque and coronary heart disease prevention and cure.