碳离子辐照诱导人外周血淋巴细胞染色体畸变的时间和剂量效应

目的：研究碳离子辐照诱导淋巴细胞染色体畸变的时间和剂量效应。方法：以加速的碳离子为辐射源,吸收剂量分别为2、4Gy的碳离子辐照人外周血淋巴细胞后,分别培养48、72、84h后收集细胞,用姊妹染色单体区别染色法分析淋巴细胞第一次分裂中期染色体畸变,以研究畸变的时间效应;吸收剂量为0、0.5、1、2、3、4Gy的碳离子辐照人外周血淋巴细胞后,培养48h,用常规染色体技术研究碳离子辐照诱导淋巴细胞染色体畸变的剂量效应。结果：辐照后分别培养48、72和84h得到的双着丝粒和着丝粒环畸变（＂双＋环＂畸变）频率没有明显差异;在0.5～4Gy剂量范围内,＂双＋环＂畸变的量效关系符合线性关系：Y=0.0005＋0.689D。结论：在本实验辐照条件下,碳离子辐射诱导淋巴细胞染色体畸变不存在时间效应,可以用48h的培养时间来研究碳离子的生物学效应,并发现染色体＂双＋环＂畸变随剂量的增加而呈线性增加。

Time and dose effects of chromosome aberrations in human blood lymphocyte induced by carbon ion irradiation

OBJECTIVE: To study the time-course and dose-response of chromosome aberrations in human blood lymphocyte induced by carbon ion irradiation. METHODS: Peripheral blood samples from volunteers were irradiated with carbon ions with a mean LET of 46 keV/μm. For the time-course study, the irradiation doses were 2 Gy and 4 Gy. First division metaphase cells were collected after different culture times of 48,72 and 84 h, and chromosome aberrations were determined by using sister chromatid differential staining method. For dese-response study, the irradiation doses were 0,0.5,1,2,3and 4 Gy. First division metaphase cells were collected after a culture time of 48 h, and chromosome aberrations were determined by using conventional chromosome technology. RESULTS: There was no significant difference between the frequencies of "dic + ring" obtained in these three culture times. The frequency of "dic + ring" increased linearly with doses, with the equation of Y = 0.0005 + 0.689D. CONCLUSION: In these irradiation conditions, there was no time-course effect in PBL chromosome damage induced by ~(12)C ions. A culture time of 48 h is acceptable for studing the biological effectiveness of carbon ions, and the number of chromosome aberrations increased linearly with dose.