兔髂动脉内膜受损后增生和c-myc基因的表达

THE STUDY ON C-MYC PROTO-ONCOGENE EXPRESSION AFTER BALLOON INJURY OF RABBIT ILIAC ARTERY

研究兔髂动脉内皮剥脱时血管壁细胞的反应特点和 c- myc基因的表达规律。用标准血管成形导管髂动脉球囊损伤 1 2只家兔的右髂总动脉后 ,分别于 3、7、40 d处死动物 ,用透射电镜观察术后 3d平滑肌细胞 ( SMC)超微结构的变化 ,光镜观察术后血管壁细胞的反应特点和 c- myc蛋白表达规律 ,同时对术后 40 d动物行血管造影。结果发现 :术后 3d兔髂总动脉中层 SMC由收缩型转变为分泌型 ,并向内膜下迁移 ,可见管腔内有血栓形成 ,1周时弹力板不完整 ,中膜 SMC排列紊乱 ,术后 40 d增生的 SMC和细胞外基质形成新生内膜 ,血管造影显示管腔狭窄 5 0 %～ 80 % ;球囊损伤段髂总动脉新生内膜 c- myc蛋白免疫组化染色为阳性 ,而对照组为阴性。结论 :球囊损伤髂动脉后可引起 SMC迁移、增生 ,其和细胞外基质一起形成新生内膜 ,管腔狭窄 ;SMC增生和 c- myc基因表达密切相关。

To well understand the molecular events regulating smooth muscle cell(SMC) proliferation following balloon jnjury of iliac artery.The SMC ultrastructure and levels of c myc proto oncogene expression in SMC were investigated. 12 white rabbits were divided into 3 groups in 3d( n =3),7d( n =3) and 40d( n =6) after balloon injury randomly.The animals were carried balloon injury to iliac artery with PTCA catheter (6 atm).We observed morphological changes of rabbit iliac artery through microscope and ultrastructure of SMC with transimissive electron microscope and the levels of c myc protein expression was assayed in 3,7 and 40d with a mouse monoclonal antibody postangioplasty.Deendothelialization of rabbit iliac artery induced a large of SMC to migrate from medium to neointimal and proliferate.The change of SMC pheotype were observed 3d after injury. These SMC displayed 'synthetic pheotype' which contained large amounts of rough endoplasmic reticulum,free ribosomes, mitochondria and little contractile appartus.There were a number of proliferative SMC in thickening neointima in 40 d;C myc protein expression was virtually undetectable in control iliac artery and detectable in the denuded iliac artery.Deendothelialization promoted SMC migration proliferation and formed neointima.C myc gene expression were closely related to SMC proliferation in the denuded artery.