Dystrophin cleavage and sarcolemma detachment are early post mortem changes on pass (Dicentrarchus labrax) white muscle

Using specific dystrophin antibodies directed against a conserved C-terminal sequence, we demonstrated that dystrophin of fish white muscle was quickly degraded by 50% within 24h and by 100% within 2 days, in parallel with titin cleavage and alpha-actinin release from Z-disks. These changes were accompanied by sarcolemma detachment from the myofibers in costameres (the structures containing dystrophin) and Z-disks weakening. For muscle stored during 2 to 6 mo before thawing, total dystrophin disappearance was observed at 4 degrees C in <8h. Dystrophin may serve as a marker for stored fish to evaluate post mortem changes or detect a thawing-freezing process.