在光动力光疗中类卟啉稀土配合物光敏作用原初反应的特征: 产生自由基I型机制的ESR研究

本文用ESR方法研究了类卟啉稀土配合物(CO2H-APPC)Gd]Cl2的光敏反应。用4-hydro-tetramethylpiperidine-N-oxide radical(4-hydro-TEMPO)作探针, 通过对其消自旋的作用, 证实(CO2H-APPC)Gd]Cl2光敏反应中有阳离子自由基(CO2H-APPC)Gd]^+产生, 加入还原剂可促使(CO2H-APPC)Gd]^+生成。经由5, 5-Dimethyl-1-pyrrolineN-oxide(DMPO)对超氧阴离子(O2^-)和羟基自由基(.OH)的自旋捕捉及对该自旋加合物DMPO-O2^-]和DMPO-OH]的ESR测定, 证实有O2^-和.OH产生, 并用SOD清除O2^-和甲酸钠清除.OH的实验, 进一步证实O2^-和.OH的产生。上述结果说明(CO2H-APPC)Gd]Cl2光敏反应存在着产生(CO2H-APPC)Gd]^+和活性氧自由基的I型机制。

Characterization of the initial photosensitization of porphyrin-like rare-earth metal complex in photodynamic therapy---ESR study of the type I mechanism of free radical producation

By means of ESR, we studied the photosensitization of porphyrin-like rareearth metal complex (CO2H-APPC)Gd]Cl2. By using 4-oxo-TEMPO as a probe and through its spin elimination, the production of cation free radical (CO2H-APPC)Gd]^+ in (CO2H-APPC)Gd]Cl2 photosensitization was established and moreover it might be promoted by using BNAH as a reducing agent. Through trapping O2^- and .OH with DMPO and measuring the ESR spectra of the spin adducts of DMPO-O2^-] and DMPO-OH], the O2^- and .OH were found to be definitely generated. These results showed the presence of oxygen radicals in (CO2H-APPC)Gd]Cl2 photosensitization, and shed light on the type I mechanism.