O'Brien J M, Sieber F
Department of Pediatrics, Medical College of Wisconsin, Milwaukee 53201.
Exp Hematol. 1989 Feb;17(2):166-70.
Merocyanine 540 (MC 540) is a photosensitizing dye with antineoplastic and antiviral properties. Because photoexcited MC 540 generates singlet molecular oxygen and possibly other reactive oxygen species there is concern that MC 540-mediated photosensitization may be mutagenic. In this paper, we report on the induction of ouabain- and 6-thioguanine-resistant mutants in Chinese hamster ovary (CHO) cells by MC 540 and light. Incubation with merocyanine 540 in the dark was not mutagenic. Simultaneous exposure to dye and high-intensity (70-75 W/m2) white or green light caused a small but significant increase in the frequency of both ouabain- and 6-thioguanine-resistant mutants. Similar increases in mutation frequencies were observed when the cells were exposed to white or green light in the absence of dye. When the fluence rate of the white light source was reduced by 50% (i.e., to 35 W/m2) but the duration of exposure doubled to keep the fluence constant, dye-mediated photosensitization and exposure to light alone generated few if any mutants. These results indicated that MC 540-mediated photosensitization is not mutagenic (as defined by the employed assays) as long as a nonmutagenic light source is used to excite the photosensitizer. They caution against the use of very powerful light sources in clinical applications of MC 540-mediated photosensitization.
部花青540（MC 540）是一种具有抗肿瘤和抗病毒特性的光敏染料。由于光激发的MC 540会产生单线态分子氧以及可能的其他活性氧物种，人们担心MC 540介导的光致敏作用可能具有致突变性。在本文中，我们报告了MC 540和光诱导中国仓鼠卵巢（CHO）细胞中对哇巴因和6-硫鸟嘌呤耐药的突变体。在黑暗中与部花青540孵育不具有致突变性。同时暴露于染料和高强度（70 - 75 W/m²）的白色或绿色光下，会使对哇巴因和6-硫鸟嘌呤耐药的突变体频率出现小幅但显著的增加。当细胞在无染料的情况下暴露于白色或绿色光时，也观察到了类似的突变频率增加。当白色光源的通量率降低50%（即降至35 W/m²）但暴露持续时间加倍以保持通量不变时，染料介导的光致敏作用以及单独的光照几乎不会产生突变体。这些结果表明，只要使用非致突变光源来激发光敏剂，MC 540介导的光致敏作用就不会致突变（按照所采用的检测方法定义）。它们提醒在MC 540介导的光致敏作用的临床应用中要谨慎使用非常强大的光源。
