Changes of proton transportation across the inner mitochondrial membrane and H~+ -ATPase in endotoxic shock rats

摘要

Objective: To investigate the changes of proton transportation across the inner mitochondrial membrane (IMM) and H~+ -ATPase of hepatocytes in endotoxic shock rats. Methods: Endotoxin from E. Coil of 5.0 mg/kg or saline of 1 ml/kg was injected into the femoral vein. The rats were sacrificed pre-injection and 1,3, 5, 8 hours after injection, and plasma and liver tissue samples were collected respectively. The liver tissue samples were used for preparation of mitochondria and submitochondrial particles ( SMPs). The proton-translocation of SMPs and H~+-ATPase, phospholipase A_2 ( PLA_2 ) activities and malondialdehyde (MDA) content, membrane fluidities of different level of mitochondria membrane and plasma MDA content were assayed. Results: (1) Five hours after E. Coli. O111B4 injection, the maximum fluorescence quenching ACMA after adding ATP, nicotinamide adenin dinucleoacid hydrogen ( NADH), and the succinate were significantly decreased (P < 0.05). The time of maximum fluorescent quenching and the half time of fluorescent quenching were significantly prolonged (P < 0.01), especially when NADH was used as a substrate. (2) The mitochondrial H~+ -ATPase activity was significantly increased at early stage of endotoxic shock (P <0.05), and significantly decreased at late stage of endotoxic shock ( P < 0.01). (3) The mitochondrial membrane bound PLA, activity, plasmal and mitochondrial MDA content were significantly increased and succinate dehydrogenase ( SDH ) activity of mitochondria decreased markedly in endotoxic shock rats (P < 0.05). (4) The mitochondrial membrane fluidity of different lipid regions was decreased, especially in the head of phospholipid. Conclusions: Proton transportation across IMM and mitochondrial H~+-ATPase activity are significantly decreased in endotoxic shock.