Spinal Peroxynitrite Contributes to Remifentanil-induced Postoperative Hyperalgesia via Enhancement of Divalent Metal Transporter 1 without Iron-responsive Element–mediated Iron Accumulation in Rats. (April 2015)

• Record Type: Journal Article
• Authors: Shu, Rui-Chen; Zhang, Lin-Lin; Wang, Chun-Yan; Li, Nan; Wang, Hai-Yun; Xie, Ke-Liang; Yu, Yong-Hao; Wang, Guo-Lin
• Is Part Of: Anesthesiology. Volume 122:Number 4(2015)
• Publication Date: 2015-04
• Subjects: Anesthesiology -- Periodicals; Anesthetics -- Periodicals; Anesthesia -- Periodicals; 617.9605
• DOI: 10.1097/ALN.0000000000000562
• Languages: English
• ISSNs: 0003-3022

Abstract

<abstract> <title> <x xml:space="preserve">Abstract</x> </title> <sec> <title>Background:</title> <p>Hyperalgesia is one of the negative consequences following intraoperative analgesia with remifentanil. Peroxynitrite is a critical determinant in nociceptive process. Peroxynitrite inactivates iron-sulfur cluster that results in mitochondrial dysfunction and the release of iron, leading to mitochondrial iron accumulation. Iron accumulation mediated by divalent metal transporter 1 (DMT1) plays a key role in <italic>N</italic>-methyl-D-aspartate neurotoxicity. This study aims to determine whether peroxynitrite contributes to remifentanil-induced postoperative hyperalgesia <italic>via</italic> DMT1-mediated iron accumulation.</p> </sec> <sec> <title>Methods:</title> <p>Behavior testing was performed in rat model at different time points. Three-nitrotyrosine, nitrated manganese superoxide dismutase, and DMT1 with/without iron-responsive element [DMT1(+)IRE and DMT1(-)IRE] in spinal cord were detected by Western blot and immunohistochemistry. Spinal iron concentration was measured using the Perl stain and atomic absorption spectrophotometer. Hydrogen-rich saline imparting selectivity for peroxynitrite decomposition and iron chelator was applied in mechanistic study on the roles of peroxynitrite and iron, as well as the prevention of hyperalgesia.</p> </sec> <sec> <title>Results:</title> <p>Remifentanil induced thermal and mechanical hyperalgesia at postoperative 48 h. Compared with control, there were higher levels of 3-nitrotyrosine (mean ± SD, hyperalgesia <italic>vs.</italic> control, 1.22 ± 0.18 <italic>vs.</italic> 0.25 ± 0.05, n = 4), nitrated manganese superoxide dismutase (1.01 ± 0.1 <italic>vs.</italic> 0.19 ± 0.03, n = 4), DMT1(-)IRE (1.42 ± 0.19 <italic>vs.</italic> 0.33 ± 0.06, n = 4), and iron concentration (12.87 ± 1.14 <italic>vs.</italic> 5.26 ± 0.61 μg/g, n = 6) in remifentanil-induced postoperative hyperalgesia, while DMT1(+)IRE was unaffected. Eliminating peroxynitrite with hydrogen-rich saline protected against hyperalgesia and attenuated DMT1(-)IRE overexpression and iron accumulation. Iron chelator prevented hyperalgesia in a dose-dependent manner.</p> </sec> <sec> <title>Conclusions:</title> <p>Our study identifies that spinal peroxynitrite activates DMT1(-)IRE, leading to abnormal iron accumulation in remifentanil-induced postoperative hyperalgesia, while providing the rationale for the development of molecular hydrogen and "iron-targeted" therapies.</p> </sec> </abstract>