碳-12重离子诱导正常人疱疹病毒-转化淋巴细胞非稳定性染色体畸变研究

Study on unstable chromosome aberrations in human Epstein-Barr virus-lymphocytes induced by heavy ion ^(12)C

目的探讨碳-12(12C)重离子诱导正常人疱疹病毒(EBV)-转化淋巴细胞染色体畸变的生物效应。方法以照射能量为165 Me V/u,剂量率为0.3~0.5 Gy/min,照射剂量分别为0.0、0.1、0.3、0.5、0.7、1.0和2.0 Gy的12C重离子来辐照对数增长期正常人EBV-淋巴细胞,分别培养至照后48、72 h收获细胞(分别设为48和72 h组),收获前2 h加秋水仙素,制片,计算染色体畸变细胞率、"双+环"畸变率以及总非稳定性畸变率,并拟合剂量-效应回归方程。结果 48 h组的"双+环"畸变率在0.3~2.0 Gy约为72 h组的2倍。2组染色体畸变细胞数量均随照射剂量的增加而增加,呈剂量-效应关系(P<0.01)。48 h组的畸变细胞率、"双+环"畸变率以及非稳定性畸变率在0.0~2.0 Gy的剂量-效应回归方程分别为Y=0.024+0.708 D-0.175 D2[校正决定系数(R2c)=0.963,P<0.01]、Y=-0.034+0.531 D-0.128 D2(R2c=0.950,P<0.01)和Y=0.009+0.868 D-0.089 D2(R2c=0.980,P<0.01);72 h组的上述指标分别为Y=0.039+0.388 D-0.084 D2(R2c=0.976,P<0.01)、Y=-0.013+0.247 D-0.062 D2(R2c=0.900,P<0.01)和Y=0.034+0.490 D-0.046 D2(R2c=0.987,P<0.01)。结论12C重离子诱导正常人EBV-转化淋巴细胞畸变随照射剂量增加而增加;染色体畸变在0.0~2.0 Gy存在一定剂量-效应关系,符合二次多项式回归模型。

Objective To study the biological effect of chromosome aberrations in human Epstein-Barr virus-lymphocytes induced by heavy ion12 C irradiation. Methods Human Epstein-Barr virus-lymphocytes in exponential phase were exposed to heavy ion12 C at the irradiation doses of 0. 0,0. 1,0. 3,0. 5,0. 7,1. 0 and 2. 0 Gy respectively,with the beam energy was 165 Me V / u and the dose rate was 0. 3-0. 5 Gy / min. The division metaphase cells were collected after different culture times of 48 and 72 hours（ respectively as 48 h group and 72 h group）,colchicines was added to the samples 2 hours before collecting. For these assays,300 cells were scored per dose and time-point to study the relationship of chromosome aberration cell rate,dicentric ＋ ring aberration rate and the unstable chromosome aberration rate,and the regression equations of dose-response were matched. Results The dicentric ＋ ring aberration rates of 0. 3-2. 0 Gy in 48 h group were double the number of that in 72 h group. Both in the two groups,the numbers of chromosome aberration cells were significantly increased with increasing irradiation dose（ P〈0. 01）,and showed dose-effect relationship. The regression equations of dose-effect of chromosome aberration cell rate,dicentric ＋ ring aberration rate and the unstable chromosome aberration rate in 48 h group were Y = 0. 024 ＋ 0. 708 D- 0. 175 D2[adjusted coefficient of determination（ R2c） = 0. 963,P〈0. 01],Y =- 0. 034 ＋ 0. 531 D- 0. 128 D2（ R2c= 0. 950,P〈0. 01）,Y = 0. 009 ＋ 0. 868 D- 0. 089 D2（ R2c= 0. 980,P〈0. 01）. The regression equations of dose-effect of chromosome aberration cell rate,dicentric ＋ ring aberration rate and the unstable chromosome aberration rate in 72 h group were Y = 0. 039 ＋ 0. 388 D- 0. 084 D2（ R2c= 0. 976,P〈0. 01）,Y =- 0. 013 ＋ 0. 247 D- 0. 062 D2（ R2c= 0. 900,P〈0. 01）,Y = 0. 034 ＋ 0. 490 D- 0. 046 D2（ R2c= 0. 987,P〈0. 01）.Conclusion It provides further evidence that the chromosome aberration in human Epstein-Barr virus-lymphocytes induced by heavy ion12 C were increased with the increasing irradiation dose,and the chromosome aberrations shows dose-effect relationship at the dose range of 0. 0-2. 0 Gy,which is in accordance with quadratic polynomial regression model.