Reddy N M, Lange C S
Department of Radiation Oncology, SUNY Health Science Center, Brooklyn 11203.
Int J Radiat Biol. 1989 Sep;56(3):239-51. doi: 10.1080/09553008914551411.
We have compared the repair kinetics of X-ray-induced sublethal damage (SLD) and potentially lethal damage (PLD) in V79 cells during postirradiation incubation in growth medium at 37 degrees C. Kinetics of SLD repair were studied by dose fractionation (D1 + D2 = 2 + 2, 4 + 2, 4 + 4, 10 + 4 and 10 + 7 Gy). Kinetics of PLD repair were studied by incubating cells with 0.5 M hypertonic saline (HS) for 20 min at various times after irradiation. The repair of SLD, after 2, 4 and 10 Gy, was complete in about 11, 23 and 62 min, respectively. This repair time was independent of the magnitude of dose D2 (test dose). The repair of PLD, after 2, 4 and 10 Gy, was also complete in about 9, 23 and 61 min, respectively. These data indicate that: (1) the kinetics of repair of SLD for a given dose are independent of the magnitude of the test dose D2; (2) the time taken to complete the repair (repair time) is dependent on dose D1, i.e. the larger the dose D1 the longer the repair time; (3) for a given dose, the repair times assayed either by dose fractionation or by HS treatment are similar; and (4) similarities in the repair times may imply that SLD and PLD are the same. The relationship between the repair kinetics and the shape of the shoulder on fractionated survival curves is discussed.
我们比较了V79细胞在37℃生长培养基中照射后孵育期间X射线诱导的亚致死损伤（SLD）和潜在致死损伤（PLD）的修复动力学。通过剂量分割（D1 + D2 = 2 + 2、4 + 2、4 + 4、10 + 4和10 + 7 Gy）研究SLD修复动力学。通过在照射后不同时间用0.5 M高渗盐水（HS）孵育细胞20分钟来研究PLD修复动力学。2 Gy、4 Gy和10 Gy照射后，SLD的修复分别在约11分钟、23分钟和62分钟完成。该修复时间与剂量D2（测试剂量）的大小无关。2 Gy、4 Gy和10 Gy照射后，PLD的修复也分别在约9分钟、23分钟和61分钟完成。这些数据表明：（1）给定剂量下SLD的修复动力学与测试剂量D2的大小无关；（2）完成修复所需的时间（修复时间）取决于剂量D1，即剂量D1越大，修复时间越长；（3）对于给定剂量，通过剂量分割或HS处理测定的修复时间相似；（4）修复时间的相似性可能意味着SLD和PLD是相同的。讨论了修复动力学与分次存活曲线肩部形状之间的关系。
