Institute of Advanced Biomedical Engineering and Science, TWIns, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan.
J Tissue Eng Regen Med. 2010 Jun;4(4):291-9. doi: 10.1002/term.241.
Electrical coupling between cardiomyocytes is important in synchronous beating and normal heart functions. Cardiomyocytes are also electrically coupled to non-cardiomyocytes. The electrical interactions between cardiomyocytes and non-cardiomyocytes, or those between separated cardiomyocytes, are important for normal heart function because abnormalities of the coupling and variation of the cell population induce pathological heart functions and arrhythmias. In this study the three-dimensional time course of the electrical interaction between two rat neonatal cardiomyocyte sheets separated by non-cardiomyocyte sheets was analysed by a multiple-electrode extracellular recording system. The two cardiomyocyte sheets separated by a single- or double-layered mouse fibroblast NIH3T3 cell sheet coupled electrically at 113 +/- 28 or 287 +/- 87 min after layering, respectively. The time course of the electrical coupling, when the single-layer NIH3T3 cell sheet was inserted, is similar to that of a layered cardiomyocyte sheet. Immunocytological analysis and dye transfer assay suggested the formation of gap junctions at heterocellular junctions of cardiomyocytes and NIH3T3 cells. On the other hand, when a double-layered NIH3T3 cell sheet was inserted, an incomplete electrical coupling of two cardiomyocyte sheets, including a conduction delay, was observed. The electrical coupling of cardiomyocyte sheets was completely blocked (conduction block) by insertion of a triple-layered NIH3T3 cell sheet, a communication-defective HeLa cell sheet or a Ca(2+)-antagonist LaCl(3)-treated cell sheet. These electrophysiological analyses of heterogeneously stacked cell sheets might provide insights into complex electrical conduction systems that resemble those of native or damaged heart and transplanted tissues.
心肌细胞之间的电偶联对于同步跳动和正常心脏功能至关重要。心肌细胞也与非心肌细胞电偶联。心肌细胞与非心肌细胞之间或分离的心肌细胞之间的电相互作用对于正常心脏功能很重要,因为偶联的异常和细胞群体的变化会导致病理性心脏功能和心律失常。在这项研究中,使用多电极细胞外记录系统分析了由非心肌细胞层分隔的两个大鼠新生心肌细胞片之间的三维时程电相互作用。当分别插入单层或双层 NIH3T3 成纤维细胞片时,两个心肌细胞片在 113 ± 28 或 287 ± 87 分钟后电偶联。插入单层 NIH3T3 细胞片时电偶联的时程与分层心肌细胞片的时程相似。免疫细胞化学分析和染料转移测定表明,在心肌细胞和 NIH3T3 细胞的异细胞连接处形成了缝隙连接。另一方面,当插入双层 NIH3T3 细胞片时,观察到两个心肌细胞片之间不完全的电偶联,包括传导延迟。插入三层 NIH3T3 细胞片、通讯缺陷的 HeLa 细胞片或钙(Ca 2+ )拮抗剂 LaCl 3 处理的细胞片完全阻断了心肌细胞片的电偶联(传导阻滞)。这些对异质堆叠细胞片的电生理学分析可能为类似天然或受损心脏和移植组织的复杂电传导系统提供了深入的了解。