[Apoptosis and DNA degradation of cardiomyocytes of mdc and C57Bl mice]

DNA destruction and apoptosis of ventricular cardiomyocytes were studied using DMX and C57Bl10/J mice. According to our electron microscope observations the cardiomyocyte nuclei undergo chromatin condensation with the nuclear membrane folding. In cardiomyocytes with significant nuclear destruction, structural disturbances in the cytoplasm are also seen. The 0.5% agarose gel electrophoresis reveals DNA fragments, sized 64 kb and more, inside the total DNA of MDX mice myocardium. No kinds of DNA fragments are available inside samples of the total DNA of C57Bl mice myocardium. Swimming during 5 min induces formation of the same type of DNA fragments inside the total of DNA of C57Bl mice myocardium, which was registered after 2 and 22 hours of the experiment. The DNA fragments disappear from the total C57Bl mice myocardium DNA within 48 h after the stress. Trypan blue evokes formation of the same 64 kb fragments inside DNA of myocardium within 24 h after injection to C57Bl mice. Electrophoresis of the total DNA with 2% agarose gel or 5% PAAG revealed no DNA samples analysed during this study. The authors conclude that DNA destruction and apoptosis characteristic features of MDX mice cardiomyocytes of mice, have a common mechanism of DNA degradation that works both after the stress of trypan blue action in case of C57Bl mice, and as a consequence of dystrophin absence in cardiomyocytes in the case of MDX mice.