【摘要】 目的:研究PPARγ基因表达与ApoE-/-小鼠主动脉斑块成份的相互关系。方法:以20和40周龄ApoE-/-小鼠(n=10/组)为研究对象,相同基因背景和周龄C57BL/6 J小鼠设为对照。采用RT-PCR和免疫印迹技术检测各组小鼠主动脉PPARγ基因和蛋白表达变化;Movat 5色套染法和油红O染色检测ApoE-/-小鼠主动脉斑块成份;免疫组织化学技术检测斑块内PPARγ、SM-actin、MOMA-2抗原表达。结合免疫荧光技术分析PPARγ基因在主动脉斑块巨噬细胞、平滑肌细胞的表达及与脂质、弹性纤维、胶原和蛋白聚糖的相互关系。结果:20和40周龄C57BL/6 J小鼠主动脉壁有少量PPARγ表达,以20周龄组明显。ApoE-/-小鼠主动脉壁和斑块内PPARγ表达增多,以斑块内表达明显(P<0.05);与20周龄组比较,40周龄组表达最显著;且斑块脂质含量丰富;弹性纤维、胶原和蛋白聚糖含量减少,血管正性重塑明显;MOMA-2表达增加,SM-actin表达降低(P<0.05)。PPARγ在斑块内巨噬细胞、血管中膜平滑肌细胞和斑块内平滑肌细胞都有表达,但以脂质含量丰富处PPARγ表达最明显。结论:PPARγ在C57BL/6 J小鼠动脉壁表达随增龄而减少;在ApoE-/-小鼠主动脉壁和斑块内PPARγ表达随AS病变进程而增加。推测ApoE-/-小鼠主动脉斑块PPARγ表达上调可能是机体一种代偿行为和自我保护机制。更多还原

【Abstract】 AIM: To investigate the relationship of PPARγ gene expression with the composition of aortic plaque in apoE-knock out mice.METHODS: PPARγ gene and protein in aortic area of 20-week-old and 40-week-old apoE-knock out mice were investigated using RT-PCR and immunoblotting.The same aged wild type mice(C57BL/6J) were served as control(n=10). The composition of aortic plaques was analyzed by Movat method and oil red O staining.The expression of antigens such as PPARγ,SM-actin and MOMA-2 in aortic plaque were compared using immunohistochemistry.The relationship of PPARγ with macrophage,smooth muscle cells(SMC),lipid,elastic fiber,collagen and proteoglycan in aortic plaque were analyzed using immunofluorescence.RESULTS: PPARγ gene and protein in aortic wall and plaque of apoE-knock out mice were more significant than that in the same aged C57BL/6J mice(P<0.05).PPARγ expression at 40-week-old apoE-knock out mice was most significant and very low in C57BL/6J mice.More PPARγ expression of gene and protein at 20-week-old C57BL/6J mice than 40-week-old C57BL/6J mice were observed.Compared with 20-week-old apoE-/-mice,the lipid pool in aortic plaque at 40-week-old apoE-/-mice were increased remarkably,while elastic fiber,collagen and proteoglycan in plaque were decreased and aortic remodeling was very significant.Even,upregulation of MOMA-2 and downregulation of SM-actin were also detected in latter(P<0.05).In addition to SMC of aortic tunica media,PPARγ also expressed in SMC and macrophages in the aortic plaque of apoE-/-mice.PPARγ was very enriched in lipid pool of the plaque.CONCLUSION: PPARγ expression level decreases with aging in C57BL/6J mice,while increases with plaque progression in apoE-knock out mice.There is positive correlation between PPARγ expression and lipid composition in plaque.The observed upregulation of PPARγ gene expression in aortic plaque may be a compensatory behavior and protective mechanism in apoE-knock out mice.更多还原