用HPRT基因突变及CBMN研究AT细胞高辐射敏感性

Study on high radiosensitivity of AT cells by HPRT gene mutation and cytokinesis-block micronucleus method

研究了毛细血管扩张性共济失调症(Ataxia?telangiectasia,AT)患者皮肤的成纤维细胞系AT5BIVA(AT细胞)的高辐射敏感性。以源于正常人皮肤的成纤维细胞系GM0639(GM细胞)为对照,利用次黄嘌呤磷酸核糖转移酶基因(Hypoxanthinephospho?ribosyltransferase,hprt)位点突变分析技术及胞质分裂阻滞微核法(Cytokinesis?Blockmicronucleusmethod,CBMN),在AT细胞和GM细胞经Coγ射线0、1、2、3、4Gy60照射后,观察比较AT细胞和GM细胞之间hprt基因位点突变频率(hprtMF)、微核率(MNF)及微核细胞率(MNCF)的差异,并分别进行曲线拟合。在各剂量点,AT细胞hprt基因突变频率、微核率及微核细胞率均明显高于GM细胞,其差别具有显著性统计意义(p<0.01);AT和GM细胞hprt基因突变频率、微核率及微核细胞率均与照射剂量呈正相关,可拟合成剂量效应直线方程y=a+bx。结果表明,毛细血管扩张性共济失调症患者AT细胞辐射敏感性显著高于GM细胞,具有高辐射敏感性。

The high radiosensitivity of fibroblast cells (AT5BIVA cells) from the skin of the Ataxia- telangiectasia (A-T) patients were studied. Using Hypoxanthine phospho-ribosyl transferase gene mutation analysis and Cytokinesis-Block micronucleus method, the hprt mutation frequence(hprtMF), the micronucleus frequencies (MNF)and micronucleus cell frequencies (MNCF)of AT and GM cells irradiated with 0, 1, 2, 3 and 4Gy of Co γ-rays 60 were observed. The difference of hprtMF, MNF and MNCF between AT and GM cells were analyzed, and dose-response curves of hprtMF, MNF and MNCF in AT and GM cells were also established. After exposure to 0, 1, 2, 3 and 4Gy of 60Co γ-rays, hprtMF, MNF and MNCF were significantly higher in AT cells than those in GM cells (p<0.01). In the two cell types, hprtMF MNF and MNCF had a positive correlation with dose, and their linear regression equations were y=a+bx. These results show that the radiosensitivity of AT cells is significantly higher than that of GM cells and AT cells are extremely sensitive to radiation.