Zou Dan, Liu Peng, Chen Ka, Xie Qi, Liang Xinyu, Bai Qian, Zhou Qicheng, Liu Kai, Zhang Ting, Zhu Jundong, Mi Mantian
Research Center for Nutrition and Food Safety, Institute of Military Preventive Medicine, Third Military Medical University; Chongqing Key Laboratory of Nutrition and Food Safety, Chongqing Medical Nutrition Research Center, Chongqing, PR China.
PLoS One. 2015 Apr 28;10(4):e0124727. doi: 10.1371/journal.pone.0124727. eCollection 2015.
Exercise tolerance is impaired in hypoxia. The aim of this study was to evaluate the effects of myricetin, a dietary flavonoid compound widely found in fruits and vegetables, on acute hypoxia-induced exercise intolerance in vivo and in vitro.
Male rats were administered myricetin or vehicle for 7 days and subsequently spent 24 hours at a barometric pressure equivalent to 5000 m. Exercise capacity was then assessed through the run-to-fatigue procedure, and mitochondrial morphology in skeletal muscle cells was observed by transmission electron microscopy (TEM). The enzymatic activities of electron transfer complexes were analyzed using an enzyme-linked immuno-sorbent assay (ELISA). mtDNA was quantified by real-time-PCR. Mitochondrial membrane potential was measured by JC-1 staining. Protein expression was detected through western blotting, immunohistochemistry, and immunofluorescence.
Myricetin supplementation significantly prevented the decline of run-to-fatigue time of rats in hypoxia, and attenuated acute hypoxia-induced mitochondrial impairment in skeletal muscle cells in vivo and in vitro by maintaining mitochondrial structure, mtDNA content, mitochondrial membrane potential, and activities of the respiratory chain complexes. Further studies showed that myricetin maintained mitochondrial biogenesis in skeletal muscle cells under hypoxic conditions by up-regulating the expressions of mitochondrial biogenesis-related regulators, in addition, AMP-activated protein kinase(AMPK) plays a crucial role in this process.
Myricetin may have important applications for improving physical performance under hypoxic environment, which may be attributed to the protective effect against mitochondrial impairment by maintaining mitochondrial biogenesis.
低氧状态下运动耐力会受损。本研究旨在评估杨梅素（一种在水果和蔬菜中广泛存在的膳食类黄酮化合物）对体内和体外急性低氧诱导的运动不耐受的影响。
雄性大鼠给予杨梅素或赋形剂7天，随后在相当于海拔5000米的气压环境下暴露24小时。然后通过跑至疲劳实验评估运动能力，并通过透射电子显微镜（TEM）观察骨骼肌细胞中的线粒体形态。使用酶联免疫吸附测定（ELISA）分析电子传递复合体的酶活性。通过实时聚合酶链反应（real-time-PCR）对线粒体DNA（mtDNA）进行定量。用JC-1染色法测量线粒体膜电位。通过蛋白质免疫印迹、免疫组织化学和免疫荧光检测蛋白质表达。
补充杨梅素可显著防止低氧状态下大鼠跑至疲劳时间的下降，并通过维持线粒体结构、mtDNA含量、线粒体膜电位和呼吸链复合体的活性，在体内和体外减轻急性低氧诱导的骨骼肌细胞线粒体损伤。进一步研究表明，杨梅素通过上调线粒体生物发生相关调节因子的表达，在低氧条件下维持骨骼肌细胞中的线粒体生物发生，此外，AMP激活的蛋白激酶（AMPK）在此过程中起关键作用。
杨梅素在改善低氧环境下的体能方面可能具有重要应用价值，这可能归因于其通过维持线粒体生物发生对线粒体损伤的保护作用。
