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载荷下的力学活动，我们开发了一种新型的碳纤维测力系统。新制造的碳纤维极大地促进了细胞膜与纤维的牢固附着。一对纤维连接到电池的两端;刚性纤维作为机械接地，柔性纤维用于应变计。通过将柔性光纤连接到压电换能器上，并将位置信号施加到驱动器上，可以使心肌细胞在较宽的载荷条件下收缩。此外，我们已经实现了用于测量细胞内钙浓度的光学系统，从而使同时记录单个心肌细胞的力和钙瞬变成为可能。我们观察到钙瞬变的强负荷依赖性，这与以前的报道形成了鲜明的对比。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。我们还测量了用GFP腺病毒转染的肌细胞产生的力。该系统可用于研究基因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.