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Superoxide Mediates Acute Liver Injury in Irradiated Mice Lacking Sirtuin 3
Journal article   Open access   Peer reviewed

Superoxide Mediates Acute Liver Injury in Irradiated Mice Lacking Sirtuin 3

Mitchell C Coleman, Alicia K Olivier, James A Jacobus, Kranti A Mapuskar, Gaowei Mao, Sean M Martin, Dennis P Riley, David Gius and Douglas R Spitz
Antioxidants & redox signaling, Vol.20(9), pp.1423-1435
03/20/2014
DOI: 10.1089/ars.2012.5091
PMCID: PMC3936509
PMID: 23919724
url
https://doi.org/10.1089/ars.2012.5091View
Published (Version of record) Open Access

Abstract

Aims: This study determined whether acute radiation-induced liver injury seen in Sirtuin3 −/− mice after exposure to Cs-137 γ-rays was mediated by superoxide anion (O 2 •− ). Results: Male wild-type (WT) and SIRT3 −/− mice were given 2×2 Gy whole-body radiation doses separated by 24 h and livers were harvested 20 h after the second dose. Ex vivo measurements in fresh frozen liver sections demonstrated 50% increases in dihydroethidium oxidation from SIRT3 −/− animals, relative to WT animals, before irradiation, but this increase was not detected 20 h after radiation exposure. In addition, irradiated livers from SIRT3 −/− animals showed significant hydropic degeneration, loss of MitoTracker Green FM staining, increased immunohistochemical staining for 3-nitrotyrosine, loss of Ki67 staining, and increased mitochondrial localization of p53. These parameters of radiation-induced injury were significantly attenuated by an intraperitoneal injection of 2 mg/kg of the highly specific superoxide dismutase mimic, GC4401, 30 min before each fraction. Innovation: Sirtuin 3 (SIRT3) is believed to regulate mitochondrial oxidative metabolism and antioxidant defenses in response to acute radiation-induced liver injury. This work provides strong evidence for the causal role of O 2 •− in the liver injury process initiated by whole-body irradiation in SIRT3 −/− mice. Conclusion: These results support the hypothesis that O 2 •− mediates acute liver injury in SIRT3 −/− animals exposed to whole-body γ-radiation and suggest that GC4401 could be used as a radio-protective compound in vivo . Antioxid. Redox Signal. 20, 1423–1435.
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