Telford W G, King L E, Fraker P J
Department of Microbiology and Public Health, Michigan State University, East Lansing 48824.
Cytometry. 1992;13(2):137-43. doi: 10.1002/cyto.990130205.
Mouse thymocytes readily undergo apoptosis-associated DNA degradation upon exposure to glucocorticoids or ionizing radiation. It has been previously shown that flow cytometric cell cycle analysis of propidium iodide-stained apoptotic thymocytes results in the appearance of a distinct cell cycle region (the A0 region) below the G0/G1 region. Cells in this region were shown to be undergoing apoptosis, and determination of apoptosis by flow cytometric analysis was proposed as a superior method for evaluating thymocyte apoptosis. In this study, a variety of DNA binding dyes with diverse primary binding mechanisms were evaluated for their ability to detect glucocorticoid and ionizing radiation-induced apoptosis in mouse thymocytes. Apoptotic thymocytes stained with DNA binding dyes from the phenanthridinium, acridine, actinomycin, chromomycinone, anthracycline, and bisbenzimidazole groups all demonstrated clearly defined A0 regions with percentages comparable to those obtained for propidium iodide. These results indicate that the appearance of the A0 region is not dependent on a particular dye binding characteristic and may be the consequence of extensive changes in chromatin structure resulting in a significant degree of dye exclusion.
小鼠胸腺细胞在暴露于糖皮质激素或电离辐射后很容易发生与凋亡相关的DNA降解。先前已经表明，对碘化丙啶染色的凋亡胸腺细胞进行流式细胞术细胞周期分析会导致在G0/G1区域下方出现一个独特的细胞周期区域（A0区域）。该区域的细胞被证明正在经历凋亡，并且提出通过流式细胞术分析来确定凋亡是评估胸腺细胞凋亡的一种更优方法。在本研究中，评估了具有不同主要结合机制的多种DNA结合染料检测小鼠胸腺细胞中糖皮质激素和电离辐射诱导凋亡的能力。用菲啶、吖啶、放线菌素、色霉素酮、蒽环类和双苯并咪唑类DNA结合染料染色的凋亡胸腺细胞均显示出明确的A0区域，其百分比与碘化丙啶获得的百分比相当。这些结果表明，A0区域的出现不依赖于特定的染料结合特性，可能是染色质结构广泛变化导致显著程度的染料排斥的结果。
