Kojima E, Tsuboi A
Division of Radiation Hazard, National Institute of Radiological Sciences, Chiba-shi.
Jpn J Cancer Res. 1992 Jul;83(7):783-8. doi: 10.1111/j.1349-7006.1992.tb01980.x.
The effects of whole-body irradiation on survival and the hematopoietic system were studied in mice treated with 5-fluorouracil (5-FU). Animals (ddY-SLC male mice, 8-10 weeks old) were injected with 5-FU (i.p.) as a single dose (150 mg/kg) at various times before or after irradiation with X-rays at graded doses (4.8 to 7.6 Gy). The treatment of mice with 5-FU 5 days before irradiation was the most effective for the reduction of radiation lethality, having a radioprotective effect. The dose reduction factor (DRF) was 1.24. However, treatment with 5-FU at 1 day and 2 hours before, or at various times after irradiation significantly increased the radiation lethality compared to the untreated controls, creating a radiosensitizing effect. The decrease or the increase of radiation lethality exhibited by 5-FU was similar to the radiation-dose relationship pattern shown by endogenous and exogenous CFU-S. The pattern of change of thrombocyte counts in the circulating blood after irradiation was greatly modified by pretreatment with 5-FU 5 days before irradiation, effectively lessening the radiation-induced depression. In contrast, the post-irradiation patterns of leukocyte and erythrocyte variation did not show any significant change due to pretreatment with 5-FU.
研究了全身照射对用5-氟尿嘧啶（5-FU）处理的小鼠存活及造血系统的影响。动物（8 - 10周龄的ddY-SLC雄性小鼠）在以分级剂量（4.8至7.6 Gy）进行X射线照射之前或之后的不同时间，腹腔注射单剂量（150 mg/kg）的5-FU。在照射前5天用5-FU处理小鼠对降低辐射致死率最为有效，具有辐射防护作用。剂量降低因子（DRF）为1.24。然而，在照射前1天和2小时或照射后的不同时间用5-FU处理，与未处理的对照组相比，显著增加了辐射致死率，产生了放射增敏作用。5-FU所表现出的辐射致死率的降低或增加与内源性和外源性脾集落形成单位（CFU-S）所显示的辐射剂量关系模式相似。照射前5天用5-FU预处理极大地改变了照射后循环血液中血小板计数的变化模式，有效减轻了辐射诱导的降低。相比之下，由于5-FU预处理，照射后白细胞和红细胞变化模式未显示任何显著变化。
