Matsuki Naoaki, Inaba Mutsumi, Ono Kenichiro
Department of Veterinary Clinical Pathobiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Japan.
J Vet Med Sci. 2002 Apr;64(4):341-7. doi: 10.1292/jvms.64.341.
Loss of adenosine-5'-triphosphate (ATP) and accumulation of inosine-5'-monophosphate (IMP) are the major purine metabolic changes in the skeletal muscle during hypoxia. This study addressed whether chemical metabolic inhibition reflects those changes in cultured skeletal myotube. For this aim, mouse-derived C2C12 myotubes were cultured in Hank's balanced saline solution containing 2 mM sodium cyanide (CN) and/or 1 mM iodoacetic acid (IAA) up to 180 min. Inhibition of oxidative phosphorylation by CN induced a minimal change in the intracellular adenine nucleotide levels during 180 min. Blockage of glycolysis with IAA caused an over 90% decrease in adenine nucleotides both in the cytoplasmic and intramitochondrial spaces, accompanied with allantoin release. Since 1 mM allopurinol entirely inhibited the allantoin generation, xanthine dehydrogenase/oxidase was found to play a key role in the purine catabolism in IAA-treated C2C12 myotubes. By the combined treatment with CN+IAA, ATP exhaustion and IMP accumulation was achieved with significant cell injury. These changes were comparable with those in skeletal muscles during hypoxia, indicating that our model with CN+IAA is well applicable to the investigation of hypoxia-induced myopathy.
缺氧期间，骨骼肌中三磷酸腺苷（ATP）的丢失和一磷酸肌苷（IMP）的积累是嘌呤代谢的主要变化。本研究探讨了化学代谢抑制是否反映了培养的骨骼肌肌管中的这些变化。为此，将小鼠来源的C2C12肌管在含有2 mM氰化钠（CN）和/或1 mM碘乙酸（IAA）的汉克平衡盐溶液中培养长达180分钟。CN对氧化磷酸化的抑制在180分钟内引起细胞内腺嘌呤核苷酸水平的最小变化。IAA阻断糖酵解导致细胞质和线粒体内空间中的腺嘌呤核苷酸减少超过90%，同时伴有尿囊素释放。由于1 mM别嘌呤醇完全抑制了尿囊素的产生，发现黄嘌呤脱氢酶/氧化酶在IAA处理的C2C12肌管中的嘌呤分解代谢中起关键作用。通过CN+IAA联合处理，实现了ATP耗竭和IMP积累，并伴有明显的细胞损伤。这些变化与缺氧期间骨骼肌中的变化相当，表明我们的CN+IAA模型非常适用于研究缺氧诱导的肌病。
