心房颤动犬心肌组织中血小板源生长因子受体β的表达

Expression of platelet-derived growth factor β receptor in atrial tissue during atrial fibrillation of dogs

目的:探讨心房颤动(房颤)时心房肌成纤维细胞血小板源生长因子受体β(PDGFR-β)的表达及在心肌重塑中的作用。方法:杂种犬10条,植入起搏器进行右心房快速起搏(520次/min),制作持续房颤模型。5条在起搏术后第2天开始给米贝地尔,共24周,为房颤+米贝地尔组;5条未服药的为单纯房颤组。另取5条未植入起搏器犬作正常对照组。观察24周后取心房肌组织,用RT-PCR检测PDGFR-βmRNA的表达,用免疫组织化学法检测PDGFR-β及Ⅲ型胶原蛋白的表达,用Van-Gieson(V-G)法检测心肌组织总胶原。结果:3组犬心肌组织中PDGFR-βmRNA的表达差异有统计学意义(F=10.017,P=0.004),房颤+米贝地尔组较单纯房颤组降低(P<0.05)。3组犬心肌组织PDGFR-β、Ⅲ型胶原和总胶原表达差异均有统计学意义(F=111.015、39.358和174.805,P均<0.001),3组间两两比较,差异均有统计学意义(P均<0.05)。结论:房颤时心房肌存在纤维化;心房肌纤维化可能与PDGFR-β信号通路无关。

Aim：To detect the expression and the effects of PDGFR-β on myocardial remodeling during atrial fibrillation.Methods：Ten dogs underwent continuous rapid atrial pacing（500 beats/min）to create persistent atrial fibrillation.In five rapidly-paced dogs,mibefradil dihydrochloride was given beginning 2 days after pacemaker implantation,continuing until the twenty-fourth week.A group of size-match dogs（n=5）without given mibefradil was used as pure atrial fibrillation group.Another group of size-matched dogs（n=5）without pacemaker implantation was used as control group.RT-PCR was used to detect the expression of PDGFR-β mRNA.Immunohistochemistry was used to detect the expressions of PDGFR-β and cardiac collagen subtype Ⅲ.Van-Gieson（V-G）method was used to detect total cardiac collagen.Results：The expressions of PDGFR-β mRNA in atrial tissue were different among the 3 groups（F=10.017,P=0.004）,which was lower in mibefradil group than that of atrial fibrillation group（P〈0.05）.The expressions of PDGFR-β,cardiac collagen subtype Ⅲ,and total cardiac collagen in atrial tissue were different among the 3 groups（F=111.015,39.358,and 174.805,P〈0.001）,which was different between each 2 groups（P〈0.05）.Conclusion：There is fibrosis in atrial myocyte during atrial fibrillation,which is not associated with PDGFR-β signaling pathway.