Weston Mark A, Patterson Michael S
Juravinski Cancer Centre, Physics Research, Hamilton, ON, Canada; Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON, Canada.
Photochem Photobiol. 2014 Jul-Aug;90(4):878-88. doi: 10.1111/php.12256. Epub 2014 Mar 14.
A technique is introduced that monitors the depletion of intracellular ground state oxygen concentration ([(3)O(2)]) during photodynamic therapy of Mat-LyLu cell monolayers and cell suspensions. The photosensitizer Pd(II) meso-tetra(4-carboxyphenyl)porphine (PdT790) is used to manipulate and indicate intracellular [(3)O(2)] in both of the in vitro models. The Stern-Volmer relationship for PdT790 phosphorescence was characterized in suspensions by flowing nitrogen over the suspension while short pulses of 405 nm light were used to excite the sensitizer. The bleaching of sensitizer and the oxygen consumption rate were also measured during continuous exposure of the cell suspension to the 405 nm laser. Photodynamic therapy (PDT) was conducted in both cell suspensions and in cell monolayers under different treatment conditions while the phosphorescence signal was acquired. The intracellular [(3)O(2)] during PDT was calculated by using the measured Stern-Volmer relationship and correcting for sensitizer photobleaching. In addition, the amount of oxygen that was consumed during the treatments was calculated. It was found that even at large oxygen consumption rates, cells remain well oxygenated during PDT of cell suspensions. For monolayer treatments, it was found that intracellular [(3)O(2)] is rapidly depleted over the course of PDT.
介绍了一种在Mat-LyLu细胞单层和细胞悬液的光动力治疗过程中监测细胞内基态氧浓度([(3)O(2)])消耗的技术。光敏剂Pd(II)中-四(4-羧基苯基)卟啉(PdT790)用于在两种体外模型中操纵和指示细胞内[(3)O(2)]。在悬液中，通过在悬液上方流动氮气并使用405 nm短脉冲光激发敏化剂，对PdT790磷光的斯特恩-沃尔默关系进行了表征。在细胞悬液持续暴露于405 nm激光期间，还测量了敏化剂的漂白和耗氧率。在获取磷光信号的同时，在不同治疗条件下对细胞悬液和细胞单层进行光动力治疗(PDT)。通过使用测量的斯特恩-沃尔默关系并校正敏化剂光漂白来计算PDT期间的细胞内[(3)O(2)]。此外，计算了治疗过程中消耗的氧量。发现即使在高耗氧率下，细胞悬液的PDT过程中细胞仍保持良好的氧合状态。对于单层治疗，发现细胞内[(3)O(2)]在PDT过程中迅速耗尽。
