Hypobaric hypoxia can cause severe brain damage and mitochondrial dysfunction,and is involved in hypoxic brain injury.However,little is currently known about the mechanisms responsible for mitochondrial dysfunction in hypobaric hypoxic brain damage.In this study,a rat model of hypobaric hypoxic brain injury was established to investigate the molecular mechanisms associated with mitochondrial dysfunction.As revealed by two-dimensional electrophoresis analysis,16,21,and36 differential protein spots in cerebral mitochondria were observed at 6,12,and 24 hours post-hypobaric hypoxia,respectively.Furthermore,ten protein spots selected from each hypobaric hypoxia subgroup were similarly regulated and were identified by mass spectrometry.These detected proteins included dihydropyrimidinase-related protein 2,creatine kinase B-type,isovaleryl-CoA dehydrogenase,elongation factor Ts,ATP synthase beta-subunit,3-mercaptopyruvate sulfurtransferase,electron transfer flavoprotein alpha-subunit,Chain A of 2-enoyl-CoA hydratase,NADH dehydrogenase iron-sulfur protein 8 and tropomyosin beta chain.These ten proteins are all involved in the electron transport chain and the function of ATP synthase.Our findings indicate that hypobaric hypoxia can induce the differential expression of several cerebral mitochondrial proteins,which are involved in the regulation of mitochondrial energy production. Hypobaric hypoxia can cause severe brain damage and mitochondrial dysfunction, and is involved in hypoxic brain injury. Host, little is currently known about the mechanisms responsible for mitochondrial dysfunction in hypobaric hypoxic brain damage. In this study, a rat model of hypobaric hypoxic brain injury. was established to investigate the molecular mechanisms associated with mitochondrial dysfunction. As revealed by two-dimensional electrophoresis analysis, 16, 21, and 36 differential protein spots in cerebral mitochondria were observed at 6, 12, and 24 hours post-hypobaric hypoxia, respectively. , ten protein spots selected from each hypobaric hypoxia subgroup were similarly regulated and were identified by mass spectrometry. These detected proteins included dihydropyrimidinase-related protein 2, creatine kinase B-type, isovaleryl-CoA dehydrogenase, elongation factor Ts, ATP synthase beta-subunit , 3-mercaptopyruvate sulfurtransferase, electron transfer flavoprotein alpha-subunit, Chain A. of 2-enoyl-CoA hydratase, NADH dehydrogenase iron-sulfur protein 8 and tropomyosin beta chain. These ten proteins are all involved in the electron transport chain and the function of ATP synthase. These are the hypothetical hypoxia can induce the differential expression of several cerebral mitochondrial proteins, which are involved in the regulation of mitochondrial energy production.