Ferrigno Andrea, Rizzo Vittoria, Bianchi Alberto, Di Pasqua Laura G, Berardo Clarissa, Richelmi Plinio, Vairetti Mariapia
Department of Internal Medicine and Therapeutics, University of Pavia, 27100 Pavia, Italy.
Department of Molecular Medicine, Fondazione IRCCS Policlinico S. Matteo, 27100 Pavia, Italy.
Biomed Res Int. 2014;2014:627434. doi: 10.1155/2014/627434. Epub 2014 Aug 27.
We investigated the effects of hepatic ischemia/reperfusion (I/R) injury on asymmetric dimethylarginine (ADMA, a nitric oxide synthase inhibitor), protein methyltransferase (PRMT) and dimethylarginine dimethylaminohydrolase (DDAH) (involved, resp., in ADMA synthesis and degradation), and the cationic transporter (CAT). Male Wistar rats were subjected to 30 or 60 min hepatic ischemia followed by 60 min reperfusion. ADMA levels in serum and bile were determined. Tissue ADMA, DDAH activity, DDAH-1 and CAT-2 protein, DDAH-1 and PRMT-1 mRNA expression, GSH/GSSG, ROS production, and lipid peroxidation were detected. ADMA was found in bile. I/R increased serum and bile ADMA levels while an intracellular decrease was detected after 60 min ischemia. Decreased DDAH activity, mRNA, and protein expression were observed at the end of reperfusion. No significant difference was observed in GSH/GSSG, ROS, lipid peroxidation, and CAT-2; a decrease in PRMT-1 mRNA expression was found after I/R. Liver is responsible for the biliary excretion of ADMA, as documented here for the first time, and I/R injury is associated with an oxidative stress-independent alteration in DDAH activity. These data are a step forward in the understanding of the pathways that regulate serum, tissue, and biliary levels of ADMA in which DDAH enzyme plays a crucial role.
我们研究了肝脏缺血/再灌注（I/R）损伤对不对称二甲基精氨酸（ADMA，一种一氧化氮合酶抑制剂）、蛋白质甲基转移酶（PRMT）和二甲基精氨酸二甲胺水解酶（DDAH）（分别参与ADMA的合成和降解）以及阳离子转运体（CAT）的影响。将雄性Wistar大鼠进行30或60分钟的肝脏缺血，随后再灌注60分钟。测定血清和胆汁中的ADMA水平。检测组织中的ADMA、DDAH活性、DDAH-1和CAT-2蛋白、DDAH-1和PRMT-1 mRNA表达、谷胱甘肽/氧化型谷胱甘肽（GSH/GSSG）、活性氧（ROS）生成以及脂质过氧化。在胆汁中发现了ADMA。I/R增加了血清和胆汁中的ADMA水平，而在缺血60分钟后检测到细胞内ADMA水平下降。在再灌注结束时观察到DDAH活性、mRNA和蛋白表达降低。在GSH/GSSG、ROS、脂质过氧化和CAT-2方面未观察到显著差异；I/R后发现PRMT-1 mRNA表达下降。肝脏负责ADMA的胆汁排泄，本文首次证明了这一点，并且I/R损伤与DDAH活性的氧化应激非依赖性改变有关。这些数据在理解调节ADMA血清、组织和胆汁水平的途径方面向前迈进了一步，其中DDAH酶起着关键作用。
