Lipid molecules are important participants in mitochondria-mediated apoptosis. This study explored the effect of mitochondrial lipids on mitochondria-mediated apoptosis, mitochondrial reactive oxygen species (ROS) production, and muscle oxidation of beef longissimus lumborum (LL, n = 6) and psoas major (PM, n = 6) during 24 h postmortem. A total of 432 lipid species matched with 21 lipid classes were identified. Remarkably, at 12 h postmortem, the levels of cardiolipin and phosphatidylserine in PM and ceramide, cardiolipin, phosphatidylserine, and sphingosine in LL increased significantly compared with 1 h postmortem, indicating that mitochondria-mediated apoptosis in beef muscle was accelerated during early postmortem. Moreover, PM had higher levels of cardiolipin and phosphatidylserine than LL, also suggesting a higher degree of apoptosis in PM during postmortem. Lipid molecules may assist the production of mitochondrial ROS and decrease the mitochondrial membrane potential (MMP) during postmortem apoptosis, resulting in muscle oxidation and the damage of antioxidant system. Notably, compared with LL, PM had higher abundance of apoptosis-related lipid molecules, a higher amount of ROS, faster diminishment in MMP, and then a higher degree of apoptosis. These findings provided new insights into the apoptosis and muscle biochemistry in beef during early postmortem.

中文翻译：

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线粒体脂质组的改变及其对死后早期牛肉细胞凋亡、线粒体活性氧产生和肌肉氧化的潜在影响

脂质分子是线粒体介导的细胞凋亡的重要参与者。本研究探讨了线粒体脂质对线粒体介导的细胞凋亡、线粒体活性氧 (ROS) 产生和牛肉腰最长肌 (LL, n = 6) 和腰大肌 (PM, n= 6) 在死后 24 小时内。共鉴定出与 21 个脂质类别相匹配的 432 种脂质种类。值得注意的是，在死后 12 小时，PM 中的心磷脂和磷脂酰丝氨酸水平以及 LL 中的神经酰胺、心磷脂、磷脂酰丝氨酸和鞘氨醇水平与死后 1 小时相比显着增加，表明线粒体介导的牛肉肌肉细胞凋亡在死后早期加速。此外，PM 比 LL 具有更高水平的心磷脂和磷脂酰丝氨酸，这也表明死后 PM 中的细胞凋亡程度更高。脂质分子可能在死后细胞凋亡过程中协助线粒体 ROS 的产生并降低线粒体膜电位 (MMP)，从而导致肌肉氧化和抗氧化系统的损伤。值得注意的是，与 LL 相比，PM具有更高丰度的凋亡相关脂质分子、更高量的ROS、更快的MMP减少，然后更高程度的细胞凋亡。这些发现为死后早期牛肉中的细胞凋亡和肌肉生化提供了新的见解。