Four stages of mitochondrial deterioration in hemorrhagic shock

It is of great importance to define the manner in which cells are damaged and how intracellular derangement becomes irreversible during shock. When supply of both oxygen and substrates to cells is limited during shock, cellular energy metabolism of vital organs is severely depressed. In this experiment, the relationship was clarified between the reversibility of shock and the cellular energy status, from the viewpoint of hepatic energy change, mitochondrial redox state, ATP synthesis of isolated mitochondria, and fragility of mitochondrial membrane in rat livers. The derangement of energy metabolism passed through a series of four stages during hemorrhagic shock. At Stage I (initial stage), the cellular energy level decreased greatly due to marked energy consumption, without any organic damages in the mitochondria. Stage II (cell distress stage) showed that cellular energy imbalance occurred due to the depressed mitochondrial activity in vivo, although it was reversible when the blood supply was restored. Stage III (transitional stage) was the phase at which mitochondrial fragility increased severely. At Stage IV (terminal stage), mitochondria were markedly damaged organically and cellular energy metabolism was not remedied by any intensive therapies, which inevitably meant the death of vital organs.