Mitochondrial
NADP+-dependent
isocitrate dehydrogenase 2 (IDH2) is a major producer of mitochondrial
NADPH, required for
glutathione (GSH)-associated mitochondrial
antioxidant systems including
glutathione peroxidase (GPx) and
glutathione reductase (GR). Here, we investigated the role of IDH2 in hepatic
ischemia-reperfusion (HIR)-associated mitochondrial injury using Idh2-knockout (Idh2-/-) mice and wild-type (Idh2+/+) littermates. Mice were subjected to either 60min of partial liver
ischemia or
sham-operation. Some mice were administered with 2-(2,2,6,6-tetramethylpiperidin-1-oxyl-4-ylamino)-2-oxoethyl) triphenylphosphonium chloride (mito-TEMPO, a mitochondria-targeting
antioxidant). HIR induced severe histological and functional damages of liver in both Idh2+/+ mice and Idh2-/- mice and those damages were more severe in Idh2-/- mice than in wild-type littermates. HIR induces dysfunction of IDH2, leading to the decreases of
NADPH level and mitochondrial GR and GPx functions, consequently resulting in mitochondrial and cellular oxidative injury as reflected by mitochondrial cristae loss, mitochondrial fragmentation, shift in mitochondrial fission,
cytochrome c release, and cell death. These HIR-induced changes were greater in Idh2-/- mice than wild-type mice. The mito-
TEMPO supplement significantly attenuated the aforementioned changes, and these attenuations were much greater in Idh2-/- mice when compared with wild-type littermates. Taken together, results have demonstrated that HIR impairs in the IDH2-
NADPH-GSH mitochondrial
antioxidant system, resulting in increased mitochondrial oxidative damage and dysfunction, suggesting that IDH2 plays a critical role in mitochondrial redox balance and HIR-induced impairment of IDH2 function is associated with the pathogenesis of
ischemia-reperfusion-induced
liver failure.