心室纤颤时心肌缝隙连接蛋白Cx43的变化

目的 观察心室纤颤(室颤)发生后缝隙连接蛋白Cx43的表达以及缝隙连接改造剂ZP123对Cx43表达的影响.方法 按照随机数字表法将30只家猪分为假手术组、模型组和ZP123干预组,每组10只.以80 V电压持续刺激动物5 s诱发室颤;致颤前15 min ZP123组给予ZP123 1μg/kg静脉推注+ZP12310μg·kg-1·h-1微量泵泵入;模型组泵入生理盐水50 ml;假手术组动物不致颤也不补液.室颤持续8 min后开胸取左心室游离壁心肌,用免疫荧光结合激光共聚焦显微镜技术检测Cx43的分布及水平,用蛋白质免疫印迹法(Western blotting)定量检测Cx43蛋白表达.结果 假手术组Cx43荧光信号强,分布均匀;模型组Cx43荧光信号弱,呈不均一分布;ZP123干预组Cx43荧光信号增强,不均一分布减轻.与假手术组比较,模型组心室肌组织Cx43荧光信号面积百分比、积分吸光度(A)值及蛋白表达均明显下降面积百分比:(0.64±0.36)%比(1.27±0.19)%,积分A值:15 201±2 613比30 634±4 975,Cx43蛋白表达:0.72±0.08比0.97±0.07,均P＜0.05];与模型组比较,ZP123干预组Cx43表达面积百分比(0.96±0.16)%,积分A值22 100±4 404,Cx43蛋白表达0.82±0.04]均明显升高(均P＜0.05).结论 室颤发生时心肌组织Cx43表达减少;应用ZP123可减少或逆转Cx43的降解.

Changes in myocardial connexin 43 during ventricular fibrillation

Objective To observe changes in connexin 43 (Cx43) after ventricular fibrillation (VF)and the effects of rotigaptide (ZP123) on Cx43. Methods Thirty domestic pigs were randomly assigned to three groups (10 in each group): sham group, model group and ZP123 group. VF was induced by an 80 V AC transthoracic shock for 5 seconds with the use of subcutaneous needles. Before the induction of VF,animals in ZP123 group were administered with ZP123 (1 μg/kg bolus+10 μg · kg-1 · h-1 dissolved in 50 ml normal saline and pumped for 15 minutes). Those in model group received 50 ml normal saline pumped for 15 minutes. For pigs in sham group VF was not induced and no fluid was given. After 8 minutes of VF,animals were euthanized and myocardial tissues were harvested along the long axis of each left ventricular free wall. Immunofluorescence combined with laser scanning confocal microscope was used to detect the distribution of Cx43. Western blotting was used for quantitative determination of Cx43 protein expression.Results Immunofluorescence signals for Cx43 in sham group were strong and regularly distributed. In model group, Cx43 signals were weak and distributed in heterogeneity, while in ZP123 group, Cx43 signals were enhanced and their distribution were much more orderly. Compared with sham group, the percentage area and the optical densities (A value) of Cx43 fluorescence signals and Cx43 protein expression were significantly decreased in model group the percentage area: (0. 64 ± 0. 36) % vs. (1.27 ± 0. 19) %, A value:15 201±2 613 vs. 30 634±4 975, Cx43 protein expression: 0. 72±0. 08 vs. 0. 97±0. 07, all P＜0. 05]. The level of Cx43 expression in ZP 123 group the percentage area (0. 96±0. 16)%, A value 22 100±4 404,Cx43 protein expression 0. 82 ±0.04] was much higher than model group (all P＜0.05). Conclusion During VF, down-regulation of myocardial Cx43 expression occurred, which could be attenuated by administration of ZP123.