Abstract
An age-related pigment, lipofuscin (LF), which accumulates in postmitotic, long-lived cells, is formed by the oxidative degradation of cellular macromolecules by oxygen-derived free radicals. In the present study we show that LF is accumulated in some myofibres, myosatellite cells and interstitial cells in the diaphragm muscles of the X chromosome-linked muscular dystrophic (mdx) mice at the age of 10 weeks when repetitive cycles of de- and regeneration of myofibres occur. In contrast, LF is virtually absent in diaphragm muscles of age-matched C57BL/10 (C57) normal control mice. Therefore, mdx muscle is more susceptible to oxidative stress than normal muscle. We hypothesise that gene-regulated cell death (apoptosis) occurs in dystrophic muscle cells that accumulate LF as a consequence of either oxidative stress or injury. We found that 74-79% of apoptotic myosatellite cells, interstitial cells and myofibres in mdx diaphragm contain accumulated or dotted LF granules, but only 12-20% of non-apoptotic cells contain LF. Apoptotic cells are very rare in the diaphragm of age-matched C57 control mice. This suggests that the regeneration of mdx diaphragm muscle initiated from myosatellite cells is impaired by their apoptosis as the result of either oxidative stress or a product of oxidative injury.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
