INTRODUCTION Carnitine is essential for long-chain fatty acid oxidation in muscle and heart. Tissue stores are regulated by organic cation/Cn transporter plasmalemmal Octn2. We previously demonstrated low carnitine in quadriceps/gluteus and heart of adult mdx mice. METHODS We studied protein and mRNA expression of Octn2, mitochondrial Octn1 and peroxisomal Octn3 in adult male C57BL/10ScSn-DMD mdx/J quadriceps, heart, and diaphragm compared to C57BL/10SnJ mice. RESULTS We demonstrated reduction in mOctn2 expression on Western blot and similar expression of mOctn1 and mOctn3 in mdx quadriceps, heart and diaphragm. There was a significant upregulation of mOctn1 and mOctn2 mRNA by qRT-PCR in mdx quadriceps and of mOctn2 and mOctn3 mRNA in mdx heart. We showed upregulation of mdx mOctn1 and mOctn3 mRNA but no increase in protein expression. DISCUSSION Dystrophin deficiency likely disrupts Octn2 expression decreasing muscle carnitine uptake thus contributing to membranotoxic long-chain acyl-CoAs with sarcolemmal and organellar membrane oxidative injury providing a treatment rationale for early L-carnitine in DMD.

中文翻译：

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有机阳离子/肉碱转运蛋白家族（Octn1，-2和-3）在mdx肌肉和心脏中的表达：早期肉碱疗法在Duchenne肌营养不良症中的意义在于改善细胞肉碱的体内稳态。

简介肉碱对于肌肉和心脏中的长链脂肪酸氧化至关重要。组织存储受有机阳离子/ Cn转运蛋白血浆Octn2调控。我们以前在成年mdx小鼠的股四头肌/臀大肌和心脏中证实了低肉碱含量。方法我们研究了成年雄性C57BL / 10ScSn-DMD mdx / J股四头肌，心脏和隔膜的Octn2，线粒体Octn1和过氧化物酶体Octn3的蛋白质和mRNA表达，与C57BL / 10SnJ小鼠相比。结果我们证明了Western blot证实mOctn2表达降低，而mdx股四头肌，心脏和隔膜中的mOctn1和mOctn3表达相似。通过qRT-PCR在mdx股四头肌中显着上调mOctn1和mOctn2 mRNA，在mdx心脏中显着上调mOctn2和mOctn3 mRNA。我们显示了mdx mOctn1和mOctn3 mRNA的上调，但蛋白表达没有增加。