不同的照射方式对小鼠造血系统残留损伤的影响

研究了剂量分割对ICR/JCL和LACA小鼠的活存率,股骨中骨髓细胞(BMC)和造血干细胞(CFU-S)数,以及CFU-S自我更新能力的影响。剂量分割对小鼠的存活率有明显的影响。在18Gy照射后2个月,接受3.0Gy 6次照射和4. 5 Gy 4次照射的小鼠分别活存40％和15％,但6.0 Gy3次照射小鼠已全数死亡。当总剂量12Gy分割成2—4次照射时,大多数小鼠能活存5个月以上。虽然每根股骨中的BMC数在照后2个月恢复至正常或接近正常水平,但股骨CFU-S含量只相当于同令对照的40％,CFU-S自我更新能力只相当于25％。这种造血残留损伤在照后11个月时仍然存在,在不同的剂量分割组之间未见明显的差别。

THE EFFECTS OF VARIOUS IRRADIATION SCHEDULES ON THE HEMOPOIETIC RESIDUAL DAMAGE IN MICE

The effects of dose fractionation on the survival rate, the numbers ofbone marrow cells (BMC) and hemopoietic stem cells (CFU-S) per femur, and the self-renewal capacity of the CPU-S in ICR/JCL and LACA mice were investigated. It wasfound that dose fractionation affected the mouse survival rate significantly. At 2 monthsafter 18 Gy irradiation. the survival rates of mice received 6 doses of 3.0 Gy and 4 dosesof 4.5 Gy were about 40% and 15% respectively, but all mice died after 3 doses of 6.0Gy. When the total dose of 12 Gy was split into 2-4 fractions, most mice survivedmore than 5 months. Although the numberof BMC per femur recovered to normal ornear normal level after 2 months of irradiation, the number of CFU-S per femur wasonly about 40% and the self-renewal capacity of the CFU-S was only about 25% of theage-paired controls. This kind of hemopoietic residual damage remained unchanged up to11 months after irradiation and no significant differences were found among the variousdose fractionation groups.