低浓度丝裂霉素C诱导抗大剂量辐射照射的适应性反应

ADAPTIVE RESPONSE INDUCED BY LOW CONCENTRATIONS OF MMC IN HUMAN PERIPHERAL LYMPHOCYTES

本文以人外周血淋巴细胞为实验材料，在血样培养至３８ｈ时给予不同浓度（０．０１～０．１μｇ／ｍＬ）丝裂霉素Ｃ（ＭＭＣ）作预先处理，４ｈ后再给予１．５ＧｙＸ射线照射，以观察化学物质和电离辐射的交叉抗性。结果表明，当ＭＭＣ处理浓度分别为０．０５，０．０７５μｇ／ｍＬ和０．０１μｇ／ｍＬ时，染色体畸变率和姊妹染色单体互换（ＳＣＥ）频率分别明显低于预期值；而当ＭＭＣ预处理浓度为０．０５、０．０７５、０．１０μｇ／ｍＬ时微核发生率明显高于预期值。提示在研究化学物质与电离辐射的交叉抗性时，不同观察指标结论可能不一致。

Samples of cultured human peripheral lymphocytes were pre treated with mitomycin C (MMC) in concentrations of 0.01～0.1 μg/mL at 34 h of incubation and then exposed to 1.5 Gy of X rays.Chromosome aberrations,sister chromatid exchanges and micronuclei for these lymphocytes were observed.The results show that the chromosome aberration rates for lymphocytes pre treated with MMC in concentrations of 0.5 and 0.075 μg/mL and the frequences of sister chromatid exchanges for lymphocytes pre treated with MMC in concentrations of 0.01 μg/mL were significantly lower than their own expected values but the rates of micronuclei for lymphocytes pre treated with MMC in concentrations of 0.05,0.075 and 0.1 μg/mL were significantly higher than the expected values.Such results suggest that for studing the cross resistance of lymphocytes to chemicals and ionizing radiation, inconsistent conclusions may be obtained if different endpoints are based on.