| Objective: Sesamin,a class of lignans,is one component of sesame oil,and there havebeen relative studies suggested some of the beneficial effects of sesamin as an antic-holesteremic agent, an antihypertensive agent and an antioxidant. This study design-ned to investigate the antiatherogenic effects of sesamin and sesame oil in high cho-lesterol diet Japanese white rabbits as the evidence of economic primary preventionfrom atherosclerosis.Methods: 1.Group: 55 Japanese white rabbits were used. Rabbits fed normal dietwere used as control group (n=6),and fed high-cholesterol diet as atherosclerotic mo-del group (n=31).The remained rabbits divided into three groups (n=6, per group)were fed the high cholesterol diet containing sesamin(4mg/d, by stomach irrigating),black sesame oil(5ml/d) and white sesame oil (5ml/d) respectively. At 5th week-end 18rabbits from these established atherosclerotic models were fed the high cholesterol dietcontaining sesamin(4mg/d, by stomach irrigating, n=6), black sesame oil(5ml/d, n=6)and atorvastatin (atorvastatinCa 10mg/d, by stomach irrigating, n=6) respecti-vely.2.Model:Bovine serum albumin (250mg/kg) were used once by ear- edge intra-venous injection to these rabbits fed high cholesterol diet at beginning of this study.3. Methods: Blood samples were taken to determine the plasma lipid and lipoproteincholesterol concentrations at the times of 0, 5th, 8th- week end using oxidase met-hods for total cholesterol(TC), triglycerides(TG), low- density lipoprotein (LDL) andhigh- density lipoprotein(HDL). At the same time determined the weight of rabbitsalso. The aortic fragments were cut and stained with hematoxylin and eosin to deter-mine the intimal thickening of aorta. The areas of the intima and media of the cross-section were determined by using a light microscope and an image analysis soft- ware.The serial cross-sections of aorta tissue were stained immunohistochemically withmouse monoclonal antibodies against rabbit macrophage and rabbit polyclonal anti-bodies against c-myc, VEGF and MMP-2 for immunohistochemical analysis. Sirius red and picric acid histochemical staining was performed to determine the col- lagenfbers. Total RNA from each frozen aorta tissue sample was extracted by using theTrizol Reagent. Equal amounts of total RNA samples were reverse transcribed intocDNA. Then according to the PCR conditions of VCAM-1, ICAM-1, MMP-2,MMP-9 and GAPDH genes and all primers for each gene amplifycation, reversetranscription and PCR were performed. And these gene expressions were determinedby semiquantitative PCR, using GAPDH as an internal standard.Results: 1.Progression phase: The weight of each group expect model group increa-sed progressively during the experimental period (P＜0.05).(1)The TC and LDL insesamin group and sesame oil (black sesame oil and white sesame oil) groups weresignificantly lower than model group(P＜0.01).(2)The aorta intima in sesamin group andsesame oil groups were significantly thinner than model group (P＜0.01),and thickerthan control group. (3)Immunohistochemical analysis suggested that the posi- tiveexpression of proteins of c-myc and VEGF gene in sesamin group and black sesameoil group were significantly lower than model group(P＜0.05). The positive expressionof MMP-2 protein in sesamin group and sesame oil groups were signify- cantly lowerthan model group(P＜0.05),and the effect of sesamin was also signi- ficantlydifferent from that of sesame oil (P＜0.05). The macrophage contents weresignificantly decreased in sesamin group and sesame oil groups. The collagen con-tent in plaque in sesamin group and black sesame oil group were significantly redu-ced than model group (P＜0.01). (4) RT-PCR analysis that VCAM-1, ICAM-1,MMP-2 and MMP-9 mRNA expression in sesamin and sesame oil groups were signi-ficantly decreased than model group,and sesamin was more effective than sesame oil ondecreasing MMP-2 and MMP-9 mRNA expression.2.Treatment phase: There were nosignificant changes in the weight of rabbits within each group during the experi-mental period. (1)The LDL in black sesame oil group were significantly lower thanmodel group (P＜0.01). The TC and LDL in se- samin group were signi- fycantly lo-wer than model group (P＜0.01).The TC,TG and LDL in atorvastatin group weresignificantly lower than model group (P＜0.01). (2) The intimal aorta and plaque forma-tion in aorta were significantly decreased in sesamin, black sesame oil and atorvastatin groups than model group (P＜0.01). (3) Immunohistochemical analysis suggested thattreatment with sesamin or atorvastatin significantly reduced the positive expres-sion ofproteins of c-myc,VEGF and MMP-2 gene; also reduced the macrophage and collagencontent compared to model group (P＜0.05, respect- tively).The positive expression ofMMP-2 protein in model group was reduced com- pared to control group(P＜0.05).(4)RT-PCR analysis that treatment with sesamin, black sesame oil or atorvastatinrespectively decreased VCAM-1,ICAM-1,MMP-2 and MMP-9 mRNA expressionsignificantly than model group.Conclusions: (1)Sesamin effectively decreased the plasma concentrations of TC andLDL, reduced the lipid deposition area, and significantly inhibited the atheromatousplaque formation as well as the macrophage accumulation within plaque induced byhypercholesterolemia and the vascular immune injury in rabbits.(2)Sesamin decree-ased the number of feom macrophages,which may relate to the anti-oxidative effect-tion as well as the inhibition of ox-LDL synthesis. (3) Sesamin inhibited plaqueformation may induced by its significant inhibition of the VCAM-1, ICAM-1 andMMP-2,MMP-9 mRNA expression. (4) Sesamin reduced the protein expression ofC-myc gene and decreased VEGF protein and inhibited increase of the VSMC. (5)Sesamin is potential to be one of green health products for economic primary preventionfrom atherosclerosis. |
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