Miyoshi N, Igarashi T, Riesz P
Department of Pathology, Fukui Medical University, Japan.
Ultrason Sonochem. 2000 Jul;7(3):121-4. doi: 10.1016/s1350-4177(99)00042-5.
The possible role of singlet oxygen in the mechanism of sonodynamic therapy, the synergistic effect of ultrasound and certain sonosensitizers, was investigated. We used 4,4'-bis(1-p-carboxyphenyl-3- methyl-5-hydroxyl)-pyrazole (DRD 156), a sensitive new reagent which reacts specifically with singlet oxygen (1O2) but not with OH radicals, superoxide anion radicals or H2O2, to produce an EPR detectable signal. Sonolysis (48 kHz) of 90% D2O oxygen-saturated PBS solutions of Hematoporphyrin or Rose Bengal did not lead to the formation of detectable EPR signals of the semiquinone radical of DRD156. In contrast, the EPR signal of the semiquinone radical of DRD156 was observed during photoirradiation of Hematoporphyrin at 505 nm or of Rose Bengal at 544 nm. These results are inconsistent with a major role for singlet oxygen formation in the sonolysis of aqueous solutions of these compounds. An alternative mechanism for sonodynamic therapy involving peroxyl and alkoxyl radicals is discussed.
研究了单线态氧在超声动力学疗法机制中的可能作用，即超声与某些声敏剂的协同效应。我们使用了4,4'-双(1-对羧基苯基-3-甲基-5-羟基)-吡唑(DRD 156)，一种新型敏感试剂，它能与单线态氧(1O2)特异性反应，但不与羟基自由基、超氧阴离子自由基或过氧化氢反应，以产生可通过电子顺磁共振(EPR)检测到的信号。对血卟啉或孟加拉玫瑰红的90% D2O氧饱和磷酸盐缓冲盐水(PBS)溶液进行超声分解(48 kHz)，未导致形成可检测到的DRD156半醌自由基的EPR信号。相反，在505 nm光照血卟啉或544 nm光照孟加拉玫瑰红的过程中，观察到了DRD156半醌自由基的EPR信号。这些结果与这些化合物水溶液超声分解过程中形成单线态氧的主要作用不一致。讨论了一种涉及过氧自由基和烷氧自由基的超声动力学疗法替代机制。
