Effect of sevoflurane postconditioning on expression of CHOP in a rat model of hemorrhagic shock and resuscitation / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effect of sevoflurane postconditioning on the expression of CCAAT/enhancer-binding protein homologous protein (CHOP) in a rat model of hemorrhagic shock and resuscitation.Methods Thirty-six healthy adult male Sprague-Dawley rats,weighing 300-350 g,were divided into 3 groups (n=12 each) using a random number tablesham operation group (group S),hemorrhagic shock and resuscitation group (group HSR) and sevoflurane postconditioning group (group SP).Hemorrhagic shock was induced by withdrawing 40% of the total blood volume from the right carotid artery over an interval of 30 min,and 1 h later the removed blood was reinfused via the left jugular vein for resuscitation.Group SP inhaled 2.4% sevoflurane for 30 min starting from the onset of reinfusion.Mean arterial pressure was monitored and recorded at a 10 min interval.Before withdrawing blood (T0),immediately after the end of withdrawing blood(T1), at 1 h after the end of withdrawing blood(T2) and immediately after the end of reinfusion (T3),blood samples were collected from the common carotid artery for blood gas analysis.At 4 days after reinfusion,6 rats of each group were selected to detect spatial learning and memory ability by using Morris water maze test.The animals were then sacrificed,brains were removed for determination of neuronal apoptosis in hippocampal CA1 area using TUNEL.The rest 6 rats in each group were sacrificed at 72 h after reinfusion,and the hippocampus was isolated to detect the expression of CHOP by Western blot.Results Compared with group S,mean arterial pressure was significantly decreased,and lactic acid concentrations were increased at T1,2 in HSR and SP groups,and the escape latency was significantly prolonged,the percentage of time staying at the target quadrant was decreased,the number of apoptotic neurons in hippocampal CA1 area was increased,and the expression of CHOP was up-regulated in group HSR (P<0.05).Compared with group HSR,the escape latency was significantly shortened,the percentage of time staying at the target quadrant was increased,the number of apoptotic neurons in hippocampal CA1 area was decreased,and the expression of CHOP was down-regulated in group SP (P<0.05).Conclusion The mechanism by which sevoflurane postconditioning improves cognitive function is related to down-regulation of CHOP expression and inhibition of apoptosis in hippocampal neurons in a rat model of hemorrhagic shock and resuscitation.