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

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(P0.05).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,P0.001),which was different between each 2 groups(P0.05).Conclusion:There is fibrosis in atrial myocyte during atrial fibrillation,which is not associated with PDGFR-β signaling pathway.