Abstract: 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 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 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.

Key words: ionizing radiation, premature chromosome condensation, the longest chromosome length and width ratio, the longest and the shortest chromosome length ratio