早熟染色体凝聚最长染色体长宽比和最长与最短染色体长度比作为估算辐射剂量指标的研究

Chromosome length to width ratio and length ratio as radiation biomarkers

目的:用花萼海绵体诱癌素A(calyculin A,CA)诱导早熟染色体凝聚(prematurc chromosome condensation,PCC),探索将G_2/M-PCC细胞中最长染色体长宽比(L/B)和最长与最短染色体长度比(L/L)用于分析电离辐射损伤和作为估算辐射剂量指标的可行性。方法:分别用0、4、8、12、16和20Gy(剂量率为1Gy/min)的^(60)Coγ射线照射外周血,培养48h后用50nmol/L CA诱导PCC。分析各射线照射剂量组G_2/M-PCC指数,并进一步分析G_2-PCC、M-PCC中L/B和L/L值的变化,建立L/B和L/L值与射线照射剂量之间的剂量-效应曲线。结果:用CA可成功诱导人外周血淋巴细胞产生PCC,G_2/M-PCC指数随着照射剂量水平的增高而降低(P<0.05)。G_2-PCC、M-PCC分裂相中的L/B和L/L值在8～20 Gy范围内显著增大(P<0.05或P<0.01),在同样照射剂量水平上L/L值较L/B值增加更快(P<0.05或P<0.01)。结论:CA诱导淋巴细胞G_2/M-PCC中的L/B和L/L值可用于电离辐射损伤程度的测定和作为估算辐射剂量的指标。

OBJECTIVE：To explore the feasibility of the longest chromosome length and width ratio（L/B）,the longest and shortest chromosome length ratio（L/L） in detecting the degree of radiation injury,observed in calyculin A（CA） induced premature chromosome condensation（PCC）.METHODS：Human peripheral blood samples were irradiated by 60Coγ-rays with the doses of 0,4,8,12,16 and 20 Gy,and cultured for 48 hours to obtain PCC with CA.The G2/M-PCC index at different doses was analyzed,and the L/B,L/L values were also calculated.The dose-response curve between L/B, L/L and absorbed dose were also established.RESULTS：PCC was successfully induced by CA,and the G_2/M-PCC index was significantly decreased with dose level（P〈0.05）.The L/B and L/L values in G2-PCC or M-PCC were significantly increased at 8-20 Gy irradiation（P〈0.05 or P〈0.01）,and L/L was higher than L/B at each dose level（P〈0.05 or P〈0.01）. CONCLUSION：The L/L and L/B values in peripheral blood G_2/M-PCC cells induced by CA could be used to quantify the extent of ionizing radiation damage.