School of Fundamental Science and Technology, Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
School of Fundamental Science and Technology, Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
Photodiagnosis Photodyn Ther. 2017 Sep;19:93-97. doi: 10.1016/j.pdpdt.2017.05.008. Epub 2017 May 11.
To obtain therapeutic condition precisely by in vitro experiment, we studied the irradiance dependence of the electrical conduction blockage caused by a photodynamic reaction using a high extracellular concentration of talaporfin sodium on a novel in vitro cardiomyocyte electrical conduction wire.
The cardiomyocyte wires were constructed on patterned cultivation cover glass, which had cultivation areas 60μm in width, and a maximum length of 10mm. The talaporfin sodium concentration was set to 20μg/mL. The photodynamic reaction with a high extracellular photosensitizer concentration was performed with a short time interval (approximately 15min) between photosensitizer exposure and irradiation. A 663-nm laser was applied to the cardiomyocyte wire, and the irradiance was varied between 3 and 120mW/cm. The cardiomyocyte electrical conduction was evaluated using the cross-correlation function of intracellular Ca probe fluorescence brightness from an upper and lower section outside the laser irradiation area of a wire every 10s, which lasted up to 600s.
The onset of electrical conduction blockage was defined by an 85% decrease in the cross-correlation function, compared with its initial value. The time for the electrical conduction blockage decreased from 600 to 300s as the irradiance was increased. Also, the probability of electrical conduction blockage was found to increase with increasing irradiance.
We found a strong dependence on the irradiance for the time and probability of electrical conduction blockage.
为了在体外实验中准确获得治疗条件，我们使用新型体外心肌细胞电传导线，在高细胞外浓度的他拉泊芬钠作用下，研究了由光动力反应引起的电传导阻断与辐照度的关系。
心肌细胞线构建在图案化培养盖玻片上，该盖玻片的培养区宽度为 60μm，最大长度为 10mm。他拉泊芬钠浓度设定为 20μg/mL。采用短时间间隔（约 15min）在细胞外暴露和照射之间进行高细胞外光敏剂浓度的光动力反应。用 663nm 激光照射心肌细胞线，辐照度在 3 到 120mW/cm 之间变化。用细胞内 Ca 探针荧光亮度的上下部分之间的互相关函数来评估心肌细胞的电传导，每 10s 测量一次，持续时间长达 600s。
与初始值相比，电传导阻断的起始定义为互相关函数降低 85%。随着辐照度的增加，电传导阻断的时间从 600 秒减少到 300 秒。此外，电传导阻断的概率随着辐照度的增加而增加。
我们发现电传导阻断的时间和概率与辐照度有很强的依赖性。
