An image analysis technique for detection of radiation-induced DNA fragmentation after CHEF electrophoresis

CHEF-electrophoresis was used as a technique to detect radiation-induced DNA breakage with special emphasis to biological relevant X-ray doses (0-10 Gy). Fluorescence detection of DNA-fragments using a sensitive image analysis system was directly compared with conventional scintillation counting of 3H-thymidine prelabelled DNA in HeLa S3 cells. It is shown that the image analysis-based fluorescence detection of fragmented DNA after ionizing radiation is as sensitive and reproducible as detection using radioactively prelabelled cells without the putative shortcomings of fluorescence detection methods described earlier (Blöcher and Kuhni 1990). Therefore, the image analysis-based detection of radiation-induced DNA fragmentation after CHEF electrophoresis seems to be the most reliable method for applications to non-cycling cells and biopsy material.