Tronov V A, Grin'ko E V, Beritashvili D R, Filippovich I V
Tsitologiia. 1991;33(2):94-102.
The in vitro gamma-irradiated mouse thymocytes were embedded in low melting agarose at 37 degrees C. After getting at 4 degrees C, the cells were lysed in neutral detergent solution containing proteinase K and ethidium bromide. Microscopic visualization of single lysed and stained cells showed the presence of the central "core" (nuclear matrix) surrounded with "halo" (relaxed nuclear DNA). During electrophoresis (2-5 V/sm, 5 min) this "halo" migrated towards the anode forming a "tail". The use of microdensitometric system provided measuring the size of the tail (L) and quantity of migrated DNA (S) for individual cells as well as obtaining the distribution of these parameters among the cells. The latter may be characteristic of heterogeneity of the cell population. It was shown that L and S increased linearly with the dose irradiation at least between 0.2 and and 5.0 Gy. In irradiated thymocyte (3 Gy) the DNA repair occurred within 10-20 min, but residual DNA damage could be observed even after 60 min of incubation. These damages may initiate the degradation of DNA in irradiated thymocytes that was observed after the repair of DNA.
体外经γ射线照射的小鼠胸腺细胞于37℃包埋在低熔点琼脂糖中。4℃放置后，细胞在含有蛋白酶K和溴化乙锭的中性去污剂溶液中裂解。对单个裂解并染色的细胞进行显微镜观察，可见中央“核心”（核基质）被“晕圈”（松弛的核DNA）环绕。在电泳过程中（2 - 5 V/cm，5分钟），这个“晕圈”向阳极迁移形成“尾巴”。使用微密度测量系统可测量单个细胞尾巴的长度（L）和迁移DNA的量（S），并获得这些参数在细胞群体中的分布情况。后者可能是细胞群体异质性的特征。结果表明，至少在0.2至5.0 Gy之间，L和S随照射剂量呈线性增加。在照射的胸腺细胞（3 Gy）中，DNA修复在10 - 20分钟内发生，但即使孵育60分钟后仍可观察到残留的DNA损伤。这些损伤可能引发照射胸腺细胞中DNA的降解，这种降解在DNA修复后被观察到。
