甘氨双唑钠对离体V_（79）细胞的放射增敏作用

RADIOSENSITIZING EFFICIENCY OF SODIUM GLYCIDIDAZOLE ON V_(79) CELLS IN VITRO

以离体细胞克隆形成法进一步研究了甘氨双唑钠（ＳＧＤＤ）对乏氧Ｖ７９细胞的放射增敏作用。结果表明：ＳＧＤＤ的毒性较低，且对乏氧细胞的毒性比有氧时强。它对有氧细胞无增敏作用，但在乏氧情况下，对Ｖ７９细胞有明显的放射增敏效果，当ＳＧＤＤ在１．３８ｍｍｏｌ／Ｌ以下时，其ＳＥＲ值随浓度的增加而增高，Ｃ１．６＝０．４８ｍｍｏｌ／Ｌ（Ｃ１．６代表ＳＥＲ为１．６时所需增敏剂的浓度），ＳＥＲ最大值２．３时的浓度为１．３８ｍｍｏｌ／Ｌ，不到ＩＤ５０的１／７０。另外，ＳＧＤＤ与ＭＩＳＯ和甲硝唑同时对比的实验，显示ＳＧＤＤ的ＳＥＲ值大于ＭＩＳＯ，并大大地高于其母体化合物甲硝唑。本研究进一步证实了我们先前分子与细胞实验的结果，ＳＧＤＤ是一种低毒、寓效，且能选择性地增强乏氧细胞的放射敏感性的放射增敏剂，有希望成为提高肿瘤放疗效果的新药。

Radiosensitizing effect of sodium glycididazole(SGDD) on the typoxic V79 cells by stanoard in vitro colon formation method has been further studied. The results showed its toxicity was low. Its ID50 in cells under hypoxic and aerobic condition were 23 .5 and 35 .7 mmol/L respectively. These indicated that SGDD showed more toxicity under hypoxic than that aerobic condition(p<0 .01 ).SGDD did not produce any radiosensitizing effect under air condition, however,irradiation under hypoxic SGDD showed radiosensitization and its SER increased as a function of drug concentration below 1 .38 mmol/L. Its C1.6 was 0 .48 mmol/L.Its maxium SER was 2. 3 at 1 .38 tnmol/L. Comparison of radiosensitizing effect ofSGDD versus MISO and its mother compound (metronidazole) under the same experimental condition, SER for SGDD, MISO and metronidazole were 1 .75, 1 .53 and 1 .07 at 0 .3 mmol/L respectively. SGDD showed more radiosensitizing efficiency than MISO and much greater than metronidazole. This study further confirms our previous results i.e. SGDD is a hypoxic radiosensi tizer with low toxic. High efficiency and selectively enhances the radiosensitivity of hypoxic cells .for tumor radiotherapy.