| Abstract:Objective:To explore whether Extract of Ginkgo Biloba(EGB) could induce the expression of heme oxygenase-1(HO-1) safely and persistently in rat's aorta and play an anti-atherosclerosis(AS) role mediated by HO-1. Methods:The 46 healthy aged of 3 months male Wistar rats were used. The rats were divided into 5 groups randomly,including control group(group A, n=8), simple high-fat diet group (group B,n=14), Extract of Ginkgo Biloba group(group C,n=8), Zinc protoporphyrinâ…¨(ZnPPâ…¨) group(group D,n=8), EGB and ZnPPâ…¨group(group E,n=8),the total experimental time was 14 weeks.The experiment include 4 steps:1.Modeling and detection of AS.A group was given normal diet while the other group received high-fat diet,and the first time in more than one time in each group were given disposable injection of vitamin D 700,000U/kg.2 rats from group B were executed at the end of 6,10,14 weeks respectively,took the 1-2 cm initial segment of descending aorta to detect the pathological changes and the AS degree.2.The research about drugs affecting HO-1 expression and its activity. AS model in the initial establishment of drug intervention began, in which rats in group C were intra-peritoneal injected with EGB 30mg/kg 1 time every 2 days;Rats in group D were intra-peritoneal injected with ZnPPIX 7.5mg/kg 1 time every 2 days.Rats in group E were intra-peritoneal injected with EGB 30mg/kg and ZnPPIX 7.5mg/kg 1 time every 2 days,The group of A and B were intra-peritoneal injected with saline 1 time every 2 days.The total experiment time is 14 weeks. At the end of the experiment,took part of the initial segment of descending aorta tissue from rats in each group to detect the expression and distribution about HO-1 protein by immunocytochemistry (IHC).The positive cells showed brown granule in cytoplasmic, counting all nucleated cells,the percentage of positive cells were calculated; The HO-1 activity of descending aorta tissue were detected. According to the principle that heme can be degraded to bilirubin by HO-1,so we could measure the output of bilirubin in the reaction system to represent the HO-1 activity.3.The research of induction and inhibition of HO-1 expression on the impact of AS and related mechanisms.At the end of experiment,descending aorta tissue were taken from all rats in each group and then fixed in 10% neutral buffered formaldehyde solution,after conventional paraffin sections and Hematoxylin and Eosin (HE) staining,the pathological changes include Vascular smooth muscle cells(VSMC),foam cells,the aortic tunica intima,tunica media were observed under light microscope.The thickness about aortic tunica intima,tunica media and its ratio and the plaque area were also measured by multi-media graphic analysis system.4.The blood was drawn via heart from all rats in each groups and used to detect the liver and renal function, blood lipids,high-sensitivity C-reactive protein(hs-CRP),monocyte chemoattractant protein-1(MCP-1) and oxidized low-density lipoprotein(ox-LDL).The rat's liver and kidney functions of every group were taken to detect the safety evaluation of EGB. Results:1.The rat model of AS was established successfully. Compared with group A, rats in group B showed that the aortic tunica intima thickening apparently and outstanding to the lumen, a large number of foam cells collected below the tunica intima,and the smooth muscle cells malalinement, polarity disappeared, the thickness ratio of intima/media increased significantly(P<0.05) at 14th weekend.2.The HO-1 expression and its activity increased significantly and the degree of AS decreased markedly in group C Compared with that in group A,B,D and E. Rats in group D got much lower HO-1 expression and its activity than any other group and with the most severe degree of AS.Group D and group E had a similar expression and activity of HO-1(P>0.05),and the degree of AS of group E was similar to group B (P>0.05) but lighter than group D(P< 0.05).3.The biochemical indicators such as blood lipid,liver and renal function,hs-CRP,MCP-1and ox-LDL were significant difference between each group.all the biochemical indicators in group D were higher than that in group B (P<0.05),but in group C were all lower than that in group B (P<0.05).4. The rat's liver and kidney functions had no significant difference between group C and the other groups.Conclusions:1.High fat diet combined with vitamin D intra-peritoneal injection could make rate AS model successfully.2.Extract of Ginkgo Biloba could induce HO-1 protein overexpression and increase its activity in rat's aorta,however this induction were blocked significantly by ZnPPâ…¨.3.Inducing HO-1 expression might be the main anti-AS mechanism of Ginkgo Biloba Extract.4. Extract of Ginkgo Biloba might existence other anti-AS mechanisms in addition to the roles of inducing HO-1 expression.5.Extract of Ginkgo Biloba administration persistently was security, no toxic or side effects were observated in this experiment.
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