Savikj Mladen, Kostovski Emil, Lundell Leonidas S, Iversen Per O, Massart Julie, Widegren Ulrika
Faculty of Medicine, University of Oslo, Oslo, Norway.
Department of Research, Sunnaas Rehabilitation Hospital, Nesodden, Norway.
Physiol Rep. 2019 Aug;7(16):e14218. doi: 10.14814/phy2.14218.
Oxidative stress promotes protein degradation and apoptosis in skeletal muscle undergoing atrophy. We aimed to determine whether spinal cord injury leads to changes in oxidative stress, antioxidant capacity, and apoptotic signaling in human skeletal muscle during the first year after spinal cord injury. Vastus lateralis biopsies were obtained from seven individuals 1, 3, and 12 months after spinal cord injury and from seven able-bodied controls. Protein content of enzymes involved in reactive oxygen species production and detoxification, and apoptotic signaling were analyzed by western blot. Protein carbonylation and 4-hydroxynonenal protein adducts were measured as markers of oxidative damage. Glutathione content was determined fluorometrically. Protein content of NADPH oxidase 2, xanthine oxidase, and pro-caspase-3 was increased at 1 and 3 months after spinal cord injury compared to able-bodied controls. Furthermore, total and reduced glutathione content was increased at 1 and 3 months after spinal cord injury. Conversely, mitochondrial complexes and superoxide dismutase 2 protein content were decreased 12 months after spinal cord injury compared to able-bodied controls. In conclusion, we provide indirect evidence of increased reactive oxygen species production and increased apoptotic signaling at 1 and 3 months after spinal cord injury. Concomitant increases in glutathione antioxidant defences may reflect adaptations poised to maintain redox homeostasis in skeletal muscle following spinal cord injury.
氧化应激促进萎缩骨骼肌中的蛋白质降解和细胞凋亡。我们旨在确定脊髓损伤是否会导致脊髓损伤后第一年人体骨骼肌氧化应激、抗氧化能力和凋亡信号的变化。在脊髓损伤后1、3和12个月从7名个体获取股外侧肌活检样本，并从7名健全对照者获取样本。通过蛋白质印迹法分析参与活性氧生成和解毒的酶以及凋亡信号的蛋白质含量。测量蛋白质羰基化和4-羟基壬烯醛蛋白加合物作为氧化损伤的标志物。通过荧光法测定谷胱甘肽含量。与健全对照者相比，脊髓损伤后1个月和3个月时，NADPH氧化酶2、黄嘌呤氧化酶和前半胱天冬酶-3的蛋白质含量增加。此外，脊髓损伤后1个月和3个月时，总谷胱甘肽和还原型谷胱甘肽含量增加。相反，与健全对照者相比，脊髓损伤12个月后线粒体复合物和超氧化物歧化酶2的蛋白质含量降低。总之，我们提供了间接证据，表明脊髓损伤后1个月和3个月时活性氧生成增加以及凋亡信号增加。谷胱甘肽抗氧化防御的同时增加可能反映了脊髓损伤后骨骼肌中为维持氧化还原稳态而进行的适应性变化。
