高温及联合^(60)Co—γ射线对L5178y细胞DNA链断裂与修复的影响

EFFECTS OF HYPERTHERMIA AND ITS COMBINATION WITH ^(60)Co-γRAYS ON DNA STRAND BREAKS AND THEIR REPAIR IN L5l78y CELLS

本实验应用灵敏度较高的同位素标记—硷洗脱法研究了高温及联合^(60)Co—γ射线对L5178y细胞DNA链断裂与修复的影响。结果表明,43℃加温30分钟能明显导致DNA链断裂,并能显著地加强γ射线引起细胞DNA断裂的效应及抑制其修复;42℃则未观察到这些作用。提示高温对DNA结构的损伤及其辐射增敏作用可能存在临界温度。加温顺序对这种辐射增敏作用有影响,照前加温效果较好。

The effects of hyperthermia and its combination with C60 -γ rays on DNA strand breaks and their repair in L517.8y cells were studied , using alkline elution technique. When cells were heated at 42℃ for 30 min there was neither detectable DNA strand break nor increase in the damage induced by r-irradiatiori. But at 43℃ for 30 min the considerable amount of DNA strand breaks was detected, and obvious increase in the damage caused by r-irradiation and the inhibition of its repair were observed. These results suggested that there seems to be a critical threshold in the effects of hyperthermia either alone or in combination with r-rays on DNA strand breaks and their repair. Time sequence could influence the effects. The effect of hyperthermia before irradiation was better.