Abstract
Oxidative stress has been associated with muscle chronic diseases and aging, and it could also influence the process of post-mortem (PM) maturation of muscle into meat. Therefore, the control of the redox balance of skeletal muscle may represent a useful therapeutic approach against muscle diseases but also an innovative strategy to improve meat production. In our first study, we used human skeletal muscle cells (myoblast-cell line LHCN-M2) to investigate for the first time the antioxidant (AO) activity and potential protective effects of Lebanese saffron extracts and its main components (safranal and crocin) on H2O2-induced cytotoxic damages. Our results showed that the pretreatment with saffron and its main components, particularly crocin, effectively increased the activity of AO enzymes (GPX, SOD) and subsequently prevented H2O2-induced oxidative stress in human myoblasts, while maintaining their myogenic regulatory genes expression (myf5, myoD). Interestingly, our results suggest that, given its higher content in crocin, saffron could be a promising functional antioxidant treatment for cell-based therapies of muscular pathologies by preventing oxidative injury and potentially delaying disease progression. In our second study, we investigated the consequences of the absence of myostatin (mstn), known to induce a beneficial antioxidant status, in the regulation of muscle PM proteolysis. We reported in myostatin-deficient (mstn KO) muscles a more pronounced degradation of myofibrillar proteins (desmin, troponin T) associated with a preserved AO status while the basal autophagic flux remains lower in this genotype. During the 24 h PM kinetics our results did not show any induction of the autophagic system or the proteasome in the muscles of WT and mstn KO mice. We further demonstrated that the acute starvation during pre-slaughter period did not influence the myofibrillary degradation profile or the redox status in PM muscle of the two genotypes. In conclusion, our results suggest that the early PM proteolysis should not been attributed to an induction of proteasome and autophagy. Further our study provides a better understanding of skeletal muscle PM changes in mstn KO mice, correlating the redox state of the PM muscle and the degradation of myofibrillar proteins. Therefore, oxidative status and proteolytic rate may have important implications for the conversion of muscle into meat.