Insights into the differences of caspase and apoptosis levels in pork longissimus thoracis muscles with different tenderness: A perspective on S-nitrosylation modification

Abstract

This study investigated the differences of caspase and apoptosis levels in pork with different tenderness from the perspective of S-nitrosylation and further explored their role during pork tenderization. Ten longissimus thoracis muscles selected from 36 individual carcasses based on shear force were divided into high (HT) and low (LT) tenderness groups (n = 5), respectively. Results demonstrated that total nitric oxide synthase activity and protein S-nitrosylation levels of LT group were higher than HT group, while myocyte apoptosis levels were lower in LT group (p < 0.05). Additionally, LT group possessed a lower caspase-3 activity while a higher abundance of intact caspase-3 and greater S-nitrosylation levels of cleaved caspase-3 (p < 0.05). However, none of the above differences were found in caspase-9 (p > 0.05). The lower tenderness in LT group might be associated with reduced caspase-3 activity resulted from increased S-nitrosylation levels of its active subunits, which delayed myocyte apoptosis and thereby lowed the degradation desmin and troponin T.