Related Experiment Video
Updated: Oct 7, 2026
Scanning Electron Microscopy of Macerated Tissue to Visualize the Extracellular Matrix
Published on: June 14, 2016
[Stress-induced DNA fragmentation in cardiomyocytes of MDX and C57Bl mice]
1Institute of Cytology RAS, St. Petersburg.
Abstract:
The study deals with apoptosis of cardiomyocytes of adult mdx mice. Our previous investigation of the total DNA from mdx mice myocardium in 0.5% agarose and 5% PAAG revealed middle sized DNA fragments about 64 kb only. The DNA electrophoresis in 5% PAAG after alpha-32P-dATP incorporation into DNA, fragments mediated by terminal transferase, showed no presence of smaller DNA fragments. The low size DNA fragments (0.2, 0.4 and 11.0 kb) were observed only following stress (a 5 min swimming in water bath) by means of alpha-32P-dATP incorporation mediated by TdT reaction. DNA fragmentation lasted for 48 h after the stress. A study of the total DNA extracts of C57B1 mice also demonstrated middle and low molecular sized DNA fragmentation 2 h after the stress under the same condition of the experiment. But during the next 48 h the signs of DNA fragmentation of the total DNA disappeared. The authors conclude that the first stage of apoptosis is a permanent property of cardiomyocytes of mdx mice.
Insights
Cardiomyocyte apoptosis in mdx mice shows DNA fragmentation, especially after stress. This DNA fragmentation is a permanent early stage of apoptosis in mdx mice, unlike in healthy mice.
Area of Science:
- Biochemistry
- Molecular Biology
- Cardiovascular Science
Context:
- Investigating cardiomyocyte apoptosis in mdx mice, a model for Duchenne muscular dystrophy.
- Previous studies identified only large DNA fragments (64 kb) in mdx mouse myocardium.
- Terminal deoxynucleotidyl transferase (TdT) reaction revealed no small DNA fragments in unstressed mdx cardiomyocytes.
Purpose:
- To investigate the presence and characteristics of DNA fragmentation in cardiomyocytes of adult mdx mice.
- To determine if stress induces DNA fragmentation in mdx mouse cardiomyocytes.
- To compare DNA fragmentation patterns between mdx and C57B1 mice following stress.
Summary:
- Low molecular weight DNA fragments (0.2, 0.4, 11.0 kb) were observed in mdx mouse cardiomyocytes exclusively after a short swimming stress, with fragmentation persisting for 48 hours.
- C57B1 mice also exhibited DNA fragmentation post-stress, but it resolved within 48 hours.
- The study concludes that the initial stage of apoptosis, characterized by DNA fragmentation, is an inherent and permanent feature of mdx mouse cardiomyocytes.
Impact:
- Provides critical insights into the early molecular mechanisms of cardiomyopathy in mdx mice.
- Highlights the role of stress in exacerbating cardiomyocyte apoptosis.
- Establishes a permanent apoptotic marker in mdx mouse cardiomyocytes for future research and therapeutic targeting.
