目的:用花萼海绵体诱癌素A(calyculin A,CA)诱导早熟染色体凝聚(premature 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20 Gy(剂量率为1 Gy/min)的<'60>Coγ射线照射外周血,培养48 h后用50 nmol/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 60Co γ, -rays with the doses of 0, 4, 8, 12, 16 and 20 Gy, and cultured for48 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 G2/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 G2/M-PCC cells induced by CA could be used to quantify the extent of ionizing radiation damage.
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