The effect of caspase-3 in mitochondrial apoptosis activation on degradation of structure proteins of Esox lucius during postmortem storage.

• Caspase-3 promoted the structure protein degradation of Esox lucius. • The role of caspase-3 inhibitor is efficacy on mitochondria and protein degradation. • Desmin and troponin-T were susceptible to degradation at the early storage. • Titin and nebulin were degraded at the later postmortem storage. This study aimed to investigate the effect of caspase-3 inhibitor in mitochondrial apoptosis activation on structure protein degradation during postmortem storage. Mitochondrial dysfunction, apoptotic factors, structure protein degradation and the myofibrillar rupture index between the control and caspase-3 inhibitor groups were determined. The results show caspase-3 inhibitor repressed the mitochondrial membrane permeability and mitochondrial swelling, as well as increased mitochondrial membrane potential, causing a decrease in the release of cytochrome c from mitochondria to cytoplasm and caspase-9/3 activities (P < 0.05). Subsequently, small myofibrillar proteins (desmin and troponin-T) were susceptible to degradation, initiating texture deterioration. By contrast, giant structure proteins (titin and nebulin) were degraded during later postmortem storage, predominantly contributing to fish softening. The results further suggest that caspase-3 is involved in degradation of structure proteins during postmortem through mitochondrial apoptosis pathways. [ABSTRACT FROM AUTHOR]