重离子^12C诱发人淋巴细胞染色体畸变和微核的研究

Chromosome aberration and micronucleus formation in human peripheral blood lymphocytes induced by ^12C heavy ions

目的 探讨不同LET重离子12C诱发人淋巴细胞的生物效应。方法 采集2名健康男性自愿献血者血样,用60Co γ射线及LET为29和148 keV/μm的12C重离子照射,剂量为0.5~5.0 Gy,剂量率为0.5 Gy/min。采用同时加秋水仙素和松胞素B的方法,检测了淋巴细胞染色体畸变双着丝粒和着丝粒环（双加环）及淋巴细胞微核。结果 29和148 keV/μm的重离子12C诱导染色体畸变和微核的剂量-效应关系分别为线性和线性平方模式。诱发的染色体畸变率随着LET的增高而增高;诱发的微核率剂量〈3.0 Gy,随着LET的增高而增高,剂量〉3.0 Gy微核率趋于饱和。148 keV/μm的12C离子诱导的染色体畸变双加环,随着培养时间的延长,从0.41~1.32增加到0.68~3.00。结论 重离子12C诱导的染色体畸变随着时间和LET的增高而增加,微核在一定剂量范围内随着LET的增高而增加,其生物效应比低LET辐射60Co γ射线强。

Objective To investigate the biological effects of 12C heavy ions with different LETs,and to construct the dose-effect curves of chromosomal aberrations and micronucleus. Methods Human peripheral blood lymphocytes were irradiated with 0.5-5.0 Gy of 60Co γ-rays, 29 and 148 keV/μm 12C with a dose rate of 0.5 Gy/min, respectively. The colchicine method and cytokinesis-blocking method were applied to measure chromosome aberrations and micronuclei formation, respectively. Results The chromosomal aberrations induced by 29 and 148 keV/μm of 12C ion had a linear dose response,while the dose-response of micronucleus induction followed to a linear-quadratic model.Chromosome aberration and micronucleus frequency increased with the LET of 12C ions. However, the micronucleus frequency increased slowly when the radiation doses exceeded 3.0 Gy.Chromosomal aberrations induced by 148 keV/μm 12C ions increased significantly when the time of colchicine treatment was prolonged. Conclusions Chromosome aberration and micronucleus induced by 12C ions increased with the LET, and the micronucleus frequency increased with dose less than 3 Gy. The biological effects of 12C ions were stronger than those of low LET irradiation of γ-rays.