犬右室流出道快速起搏后急性期缝隙连接蛋白43的重构

目的采用快速心室流出道起搏制作犬急性流出道室性心动过速(VT)模型,观察心室肌缝隙连接蛋白43(Cx43)含量和分布的改变。方法20只犬随机分为对照组和VT组。将刺激电极放置右室流出道心外膜,对照组不予快速起搏,VT组以180次/分频率行快速起搏模拟VT,起搏120min后开胸取流出道间隔部的左室侧和右室侧心肌组织,用Western blot检测Cx43的含量,用免疫荧光抗体标记激光共聚焦显微镜检测Cx43的分布。结果VT组左室侧和右室侧心肌组织Cx43含量较对照组心肌组织明显降低,端端分布减少(左、右室侧荧光斑面积分别为0.45±0.09μm2/μm3 vs 2.29±0.21μm2/μm3;0.26±0.12μm2/μm3 vs 1.46±0.25μm2/μm3;P均<0.01),侧侧分布相对增加,以细胞间端端连接减少为主,二者均呈现不均一分布。结论快速右室流出道起搏可致右室流出道心肌Cx43的重构。

Connexin43 remodeling in acute stage induced by rapid pacing in dog right ventricular outflow tract

Objective To investigate the changes of connexin (Cx) 43 levels and distribution in dog with right ventricular outflow tract(RVOT) tachycardia induced by rapid pacing. Methods 20 dogs were randomized into two groups (n=10): normal control group and ventricular tachycardia(VT) group . VT was produced by RVOT pacing(180bpm). This sections of the right ventricle side and left ventricle side of RVOT septum were immunolabeled with antibodies against Cx43 and analysed by immunofluorescence and confocal laser scanning microscopy to examine Cx43 contents and their distribution. Results In VT group , Cx43 levels decreased significantly comparing with those in the normal control group (CX43 levels in left and right ventricle side were 0.45±0.09 μm2/μm3 vs 2.29±0.21 μm2/μm3;0.26±0.12 μm2/μm3 vs 1.46±0.25 μm2/μm3;respectively ,all P<0.01) and they were mainly located at the side to side interconnections instead of being confined to the intercalated discs as observed in the normal control group. The heterogeneous distribution in Cx43 as measured in the VT group were also observed. Conclusion Cx43 remodeling with redistribution and reduction of protein expression can be induced by ventricular tachycardia after rapid right ventricular outflow tract pacing.