Mitochondrial oxidative stress-mediated ferroptosis as a contributing factor of refrigerated beef tenderness: From mitochondrial biochemistry and proteomics perspective

Abstract

This study aimed to investigate the mechanism of ferroptosis mediated by mitochondrial oxidative stress and its potential associations with tenderness of beef during refrigeration. Results showed that mitochondrial reactive oxygen species (ROS) reached a maximum at day 3 (116.67 ± 8.50 mg protein), the degree of mitochondrial swelling, mitochondrial membrane permeability increased with the increase of refrigeration time, and mitochondrial free iron content increased significantly (p < 0.05), while mitochondria showed the morphological features of ferroptosis. In addition, the decreased levels of reduced glutathione, total antioxidant capacity and the activity of glutathione peroxidase, and the accumulation of malondialdehyde reflected an imbalance in mitochondrial antioxidant defense system, presenting the physiological characteristics of ferroptosis. Furthermore, mitochondrial TMT quantitative proteomics identified 7 differentially expressed proteins (DEPs) enriched to the ferroptosis pathway, including ACSL1, LOC788801, ACSL4, PRNP, VDAC2, ACSL3 and LPCAT3, which were primarily involved in lipid metabolism pathway and were the major mitochondrial pathway involved in ferroptosis during beef refrigeration. Besides, ROS and lipid peroxidation from mitochondrial oxidative stress-mediated ferroptosis attacked tissue myofibril structure and increased myofibrillar fragmentation index, which promoted the improvement of postmortem meat tenderness. These findings provided new perspectives on the role of mitochondria in cell death and the effect of ferroptosis on muscle tenderization.