Effect of sevoflurane postconditioning on expression of activating transcription factor 6 in brain tissues 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 activating transcription factor 6 (ATF6) in the brain tissues in a rat model of hemorrhagic shock and resuscitation.Methods Thirty-six pathogen-free healthy adult male Sprague-Dawley rats,weighing 300-350 g,were randomized into 3 groups (n=12 each) using a random number tablesham operation group (group S);hemorrhagic shock and resuscitation group (group HSR);sevoflurane postconditioning group (group SP).Hemorrhagic shock was induced by withdrawing blood (40％ of the total blood volume) from the right common carotid artery over an interval of 30 min,and 1 h later the animals were resuscitated with infusion of the shed blood via the left jugular vein over 30 min.In group SP,2.4％ sevoflurane was inhaled for 30 min starting from the onset of infusion of the shed blood.Mean arterial pressure was recorded before withdrawing blood (T0),immediately after the end of withdrawing blood (T1),at 30 min after the end of withdrawing blood (T2),before infusion of the shed blood (T3),and immediately after infusion of the shed blood (T4).The arterial blood samples were obtained at T0,T1,T3 and T4 for blood gas analysis.At 72 h after infusion of the shed blood,6 rats were selected from each group,and cognitive function was assessed by Y-maze test.The animals were then sacrificed,and brains were removed and sliced for determination of the expression of caspase-12 in hippocampal CA1 region by immunohistochemistry.The rest 6 rats in each group were sacrificed at 72 h after infusion of the shed blood,and the hippocampus was isolated for determination of the expression of ATF6 and caspase-12 by Western blot.Results Compared with group S,mean arterial pressure was significantly decreased at T1-3 (P＜0.05),the pH value and base excess were significantly decreased at T1.3,and the blood lactic acid was significantly increased at T1,3 in HSR and SP groups,and the number of total training was significantly increased,the rate of memory retention was significantly decreased,the expression of caspase-12 in hippocampal CA 1 region was significantly up-regulated,and the expression of ATF6 and caspase-12 in hippocampal tissues was significantly up-regulated in group HSR (P＜ 0.05).Compared with group HSR,the number of total training was significantly decreased,the rate of memory retention was significantly increased,the expression of caspase-12 in hippocampal CA1 region was significantly down-regulated,and the expression of ATF6 and caspase-12 in hippocampal tissues was significantly down-regulated in group SP (P＜0.05).Conclusion The mechanism by which sevoflurane postconditioning improves cognitive function is related to down-regulation of ATF6 expression in the brain tissues in a rat model of hemorrhagic shock and resuscitation.