摘要
采用荧光分光光度法对裂解ＤＮＡ进行定量，并用琼脂糖凝胶电泳法定性研究Ｘ射线全身照射后小鼠胸腺细胞凋亡。结果表明，４ＧｙＸ射线照后２小时胸腺细胞凋亡开始增加，于照后１４小时达峰值，尔后呈下降趋势。ＤＮＡ裂解率在照后２４小时降至１４小时的５０％，这可能是内环境中巨噬细胞吞噬凋亡小体所致。在照射后１４小时研究其剂量－效应关系发现，高剂量照射使ＤＮＡ裂解明显增多，形成１８０ｂｐ（ｂａｓｅｐａｉｒｓ）左右或其整倍数的ＤＮＡ断片，电泳呈现＂梯形图谱＂；而低剂量辐射可使ＤＮＡ裂解率降低。剂量－效应曲线呈Ｊ型。
Radiation-induced apoptosis of thymocytes in mice was quantified by measuring the percentage of DNA fragmentation by fluorescence spectrophotometry, and qualitatively analysed by agarose electrophoresis. The results showed that DNA fragmentation of thymocytes began to increase 2 hours after exposure to 4Gy, reaching its peak value at 14 hours. After that the percentage of DNA fragmentation came down to about 50 % of the peak value at 24 hours. It was found that the apoptosis could be induced by high dose irradiation. A typical 'ladder pattern' appeared on agarose gel electrophoresis after 1-4Gy irradiation. The pattern of fragmentation represents oligonucleosomes with approximately 180bp and its multiples. The dose-effect relationship of DNA fragmentation as measured by fluorescence spectrophotometry after whole-body irradiation with 0. 025-4. 0Gy showed a J-shape curve with significantly reduced apoptosis at low doses.
出处
《中华放射医学与防护杂志》
CAS
CSCD
北大核心
1996年第5期296-298,共3页
Chinese Journal of Radiological Medicine and Protection
