Development of a Gene Transfer and Functional Evaluation System for an Isolated Single Cardiac Myocyte as a model for the Gene Therapy

为了研究单个心肌细胞在大范围负荷下的机械活动，我们开发了一种新型的碳纤维力测量系统。新制备的碳纤维极大地促进了细胞膜与纤维的牢固附着。一对纤维附着在细胞的两端；刚性纤维作为机械接地，柔性纤维作为应变计。通过将柔性光纤连接到压电转换器上，并将位置信号施加到驱动器上，我们可以使肌细胞在大范围的负载条件下收缩。此外，我们已经实现了测量细胞内钙浓度的光学系统，从而可以同时记录单个心肌细胞的力和钙瞬态。我们观察到钙瞬态的强负荷依赖性，这与之前的报道有明显的对比。该系统的反馈控制也使我们能够研究单个心肌细胞在生理负荷序列下的功能。我们还测量了转染GFP腺病毒的肌细胞产生的力。该系统可用于研究遗传干预下心肌细胞的机械活动，从而为心力衰竭的研究提供有用的工具。

In order to study the mechanical activity of a single cardiac myocyte under a wide range of load, we have developed a novel force measurement system using carbon fibers. Newly fabricated Carbon fibers greatly facilitate the firm attachment of cell membrane to the fibers. A pair of fibers was attached to both ends of the cell ; the rigid fiber as a mechanical ground and the compliant fiber for the strain gauge. By connecting the compliant fiber to the piezoelectric translator and applying the position signal to the driver, we could make the myocyte contract under wide range of loading conditions. Furthermore, we have implemented the optical system for the measurement of intracellular calcium concentration thus the simultaneous recording of force and calcium transient of a single cardiac myocyte was made possible. We observed a strong load dependence of calcium transient, which shows clear contrast to the previous reports. Feedback control of the system also enabled us to study the function of a single cardiac myocyte under physiological loading sequence. We have also measured the force developed by a myocyte transfected with GFP adenovirus. This system can be a useful tool in studying the mechanical activity of the cardiac myocyte under genetic interventions thus serving as a useful tool in the study of heart failure.