title: Methane ameliorates spinal cord ischemia-reperfusion injury in rats: Antioxidant, anti-inflammatory and anti-apoptotic activity mediated by Nrf2 activation.
abstract: Methane is reported to have antioxidant, anti-inflammatory and anti-apoptotic properties. We investigated the potential neuroprotective effects of methane-rich saline (MS) on spinal cord ischemia-reperfusion injury and determined that its therapeutic benefits are associated with the activation of nuclear factor erythroid 2-related factor 2 (Nrf2). Rats received 9min of spinal cord ischemia induced by occlusion of the descending thoracic aorta plus systemic hypotension followed by a single MS treatment (10ml/kg, ip) and 72h reperfusion. MS treatment attenuated motor sensory deficits and produced high concentrations of methane in spinal cords during reperfusion, which increased Nrf2 expression and transcriptional activity in neurons, microglia and astrocytes in the ventral, intermediate and dorsal gray matter of lumbar segments. Heme oxygenase-1, superoxide dismutase, catalase and glutathione were upregulated; and glutathione disulfide, superoxide, hydrogen peroxide, malondialdehyde, 8-hydroxy-2-deoxyguanosine and 3-nitrotyrosine were downregulated in MS-treated spinal cords. MS treatment reduced neuronal apoptosis in gray matter zones, which was consistent with the suppression of cytochrome c release to the cytosol from the mitochondria and the activation of caspase-9 and -3. Throughout the gray matter, the activation of microglia and astrocytes was inhibited; the nuclear accumulation of phosphorylated nuclear factor-kappa B p65 was reduced; and tumor necrosis factor α, interleukin 1β, chemokine (C-X-C motif) ligand 1, intercellular adhesion molecule 1 and myeloperoxidase were decreased. MS treatment attenuated blood-spinal cord barrier dysfunction by preventing the expression and activity of matrix metallopeptidase-9 and disrupting tight junction proteins. Consecutive intrathecal injection of specific siRNAs targeting Nrf2 at 24-h intervals 3 days before ischemia reduced the beneficial effects of MS. Our data indicate that MS treatment prevents IR-induced spinal cord damage via antioxidant, anti-inflammatory and anti-apoptotic activities that involve the activation of Nrf2 signaling. Thus, methane may serve as a novel promising therapeutic agent for treating ischemic spinal cord injury.
authors.affiliation: Department of Anesthesiology, Fuzhou General Hospital of PLA, Fuzhou 350025, Fujian Province, People's Republic of China.
authors.forename: Liping
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Changhai Hospital, Second Military Medical University, Shanghai 200433, People's Republic of China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Yao
authors.affiliation: Department of Anesthesiology, Xinyi People's Hospital, Xinyi 221400, Jiangsu Province, People's Republic of China.
authors.forename: Rong
authors.initials: R
authors.lastname: He
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Changhai Hospital, Second Military Medical University, Shanghai 200433, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Meng
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Changhai Hospital, Second Military Medical University, Shanghai 200433, People's Republic of China.
authors.forename: Na
authors.initials: N
authors.lastname: Li
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Changhai Hospital, Second Military Medical University, Shanghai 200433, People's Republic of China.
authors.forename: Dan
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Department of Diving and Hyperbaric Medicine, Faculty of Naval Medicine, Second Military Medical University, Shanghai 200433, People's Republic of China.
authors.forename: Jiajun
authors.initials: J
authors.lastname: Xu
authors.affiliation: Department of Navy Aviation Medicine, Faculty of Naval Medicine, Second Military Medical University, Shanghai 200433, People's Republic of China.
authors.forename: Ouyang
authors.initials: O
authors.lastname: Chen
authors.affiliation: Graduate Management Unit, Changhai Hospital, Second Military Medical University, Shanghai 200433, People's Republic of China.
authors.forename: Jin
authors.initials: J
authors.lastname: Cui
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Changhai Hospital, Second Military Medical University, Shanghai 200433, People's Republic of China.
authors.forename: Jinjun
authors.initials: J
authors.lastname: Bian
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Changhai Hospital, Second Military Medical University, Shanghai 200433, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Anesthesiology, Fuzhou General Hospital of PLA, Fuzhou 350025, Fujian Province, People's Republic of China. Electronic address: cgzssq2000@sina.com.
authors.forename: Guozhong
authors.initials: G
authors.lastname: Chen
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Changhai Hospital, Second Military Medical University, Shanghai 200433, People's Republic of China. Electronic address: dengphd1@hotmail.com.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Deng
mesh_terms: D021581:Active Transport, Cell Nucleus; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D000975:Antioxidants / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000378:metabolism; D018925:Chemokines / Q000378:metabolism; D004353:Drug Evaluation, Preclinical; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D008697:Methane / Q000494:pharmacology; D017628:Microglia / Q000187:drug effects / Q000378:metabolism; D051267:NF-E2-Related Factor 2 / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology*; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000188:drug therapy*; D015398:Signal Transduction; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D020760:Spinal Cord Ischemia / Q000188:drug therapy*
chemical_list: D000893:Anti-Inflammatory Agents; D000975:Antioxidants; D015815:Cell Adhesion Molecules; D018925:Chemokines; D051267:NF-E2-Related Factor 2; D016328:NF-kappa B; D018696:Neuroprotective Agents; C495637:Nfe2l2 protein, rat; D020780:Matrix Metalloproteinase 9; C572337:Mmp9 protein, rat; D008697:Methane
keywords: Methane; Neuroinflammation; Neuronal apoptosis; Nuclear factor erythroid 2-related factor 2; Oxidative stress; Spinal cord ischemia-reperfusion injury