The Effects Of Simvastatin On The Expression Of HMGB-1 In Atherosclerotic Rats

Objective1.Investigate the best method to induce the atherosclerotic rat model, and observe the histopathology change in the atherosclerotic plaques.2.Observe the protein and gene expression of HMGB-1 in atherosclerotic rats,to discover the mechanism related with inflammation of atherosclerrosis.3.Observe the effects of Simvastatin on the protein and gene expression of HMGB-1 and morphological of the atherosclerotic plaques in atherosclerotic rats,to discover the protective mechanism of Simvastatin for atherosclerrosis.Methods1.Four methods were used to induce atherosclerotic model,including: simple high fat diet feeding,high fat diet feeding with gastric perfusion of vitamin D3,and gastric perfusion of vitamin D3 with high fat food(splashed oil on the normal rat food with yolks and peanuts),compared these methods to discover which was the best one, and histopathology change of the atherosclerotic plaques in aorta were observed by normal and histopathologic sections and Hematoxylin staining.2.The protein expression of HMGB-1 of the atherosclerotic plaques in aorta were evaluated by immunohistochemistry,and the gene expression of it were measured with real time PCR.3.The atherosclerotic rats were treated with Simvastatin(2.5mg/kg/d, gatric perfusion) for 2 or 4 weeks,and used above methods to observe the histopathology change and evaluate the protein and gene expression of HMGB-1 in the atherosclerotic plaques of aorta.Results1.The body weight of the rats with simple high fat diet feeding increased unobviously,the endarterium of aorta were smooth,without atherosclerotic plaques after 2 months;in the rats with high fat diet feeding and gastric perfusion of vitamin D3,the ring-shape calcified atherosclerotic plaques were found in the all endarterium of aorta.2.Simvastatin could inhibit the formation of the atherosclerotic plaques obviously:the area of plaques decreased evidently in 2 weeks treated group,and the decline degree in the 4 weeks treated group were more obvious than the 2 weeks treated group,showing the miliary atherosclerotic plaques,and in some rats,only the endarterium were not smooth without obvious atherosclerotic plaques.3.The expression of HMGB-1 in the atherosclerotic plaques:(1) immunohistochemistry:in normal vessels,the expression of HMGB-1 located in the vascular endothelial cells,smooth muscle cells and the nuclei of the fibroblastl;the expression of HMGB-1 were enhanced in the area infiltrted with inflammtory cells and in the matrix around the necrotic area,in the former,mainly located in the nuclei of monocyte-macrophage,cytoplasm and stroma,while in the latter, mainly distributed in the edge of the necrotic area;the opositive expression of HMGB-1 were higher in the simple high fat diet feeding group comparing with the simvastatin 4 weeks treated group,and lower in the simvastatin 2 week2 treated group comparing with simple high fat diet group,while higher than 4 weeks treated group.(2)The gene expression in the atherosclerotic plaques:the HMGB-1 mRNA expression in the all atherosclerotic model groups increased comparing with contral group,the discrepancy were significant(p);in the simvastatin treated group,the gene expression of HMGB-1 were lower than the simple high fat diet group,while more higher than the contral group,and in the 2 weeks treated group were higher than in the 4 weeks treated group.Conclusion1.Gastric perfusion of Vitamin D3 once a week(3 times) combined with high fat diet could induce the atherosclerotic model successfully and decrease the mortality rate,so,it is a good method to induce the atherosclerotic model.2.The protein and gene expression of HMGB-1 in the arota vessels of the atherosclerotic rats all enhanced obviously,and the expression change of HMGB-1 were related with the degree of the atherosclerotic plaques.3.Simvastatin could alleviate the formation of the plaques in the atherosclerotic rats,decrease the protein and gene expression of HMGB-1,then protected the vessels by alleviating the inflmmation.