Tsoncheva V L, Kirov K S, Valkova C A, Milchev G I
Department of Cell Biology, Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia.
Z Naturforsch C J Biosci. 2001 Jul-Aug;56(7-8):660-5. doi: 10.1515/znc-2001-7-827.
To assess the lethal doses of gamma radiation and corresponding apoptotic response in new established human melanoma cell lines we exposed exponentially growing cultures to 8-100 Gy gamma radiation. The apoptosis and cell survival were determined by trypan blue exclusion, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) reaction, agarose gel electrophoresis, colony forming assay, and long-term survival assay. The maximal DNA fragmentation 3 days after irradiation was observed in cultures irradiated with 20 Gy (36.9% TUNEL positive cells). The cultures irradiated with 50 and 100 Gy contained 18.7% and 16.4% TUNEL positive cells, respectively. Cultures exposed to 8 and 20 Gy gamma radiation recovered by week 3-4. Lethally irradiated (50 and 100 Gy) cultures which contained less apoptotic cells by day 3 died by week 5. A detectable increase in melanoma cell pigmentation after irradiation was also observed. The survival of human melanoma cell cultures after exposure to gamma radiation does not correlate with the level of apoptotic cells by day 3. At high radiation doses (> 50 Gy) when the radiation induced cell pigmentation is not inhibited the processes of apoptotic DNA fragmentation might be preferentially inactivated.
为了评估新建立的人黑色素瘤细胞系中γ辐射的致死剂量及相应的凋亡反应，我们将呈指数生长的培养物暴露于8 - 100 Gy的γ辐射下。通过台盼蓝排斥法、末端脱氧核苷酸转移酶介导的dUTP缺口末端标记（TUNEL）反应、琼脂糖凝胶电泳、集落形成试验和长期存活试验来确定细胞凋亡和细胞存活情况。照射后3天，在接受20 Gy照射的培养物中观察到最大程度的DNA片段化（36.9%的TUNEL阳性细胞）。接受50 Gy和100 Gy照射的培养物中，TUNEL阳性细胞分别占18.7%和16.4%。暴露于8 Gy和20 Gyγ辐射的培养物在第3 - 4周恢复。在第3天含有较少凋亡细胞的致死性照射（50 Gy和100 Gy）培养物在第5周死亡。照射后还观察到黑色素瘤细胞色素沉着有可检测到的增加。人黑色素瘤细胞培养物在暴露于γ辐射后的存活情况与第3天的凋亡细胞水平无关。在高辐射剂量（> 50 Gy）下，当辐射诱导的细胞色素沉着未被抑制时，凋亡DNA片段化过程可能会优先失活。
