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Objective To evaluate the role of mitochondrial permeability transition pore (mPTP)in reduction of brain injury by sevoflurane postconditioning in a rat model of hemorrhagic shock and resuscitation (HSR).Methods Ninety pathogen-free healthy adult male Sprague-Dawley rats,weighing 300-350 g,were divided into 5 groups (n =18 each) using a random number table:sham operation group (group S),group HSR,sevoflurane postconditioning group (group SP),sevoflurane postconditioning plus atractyloside (ATR,a specific mPTP opener) group (group SP + ATR) and ATR group.Hemorrhagic shock was produced by withdrawing 40％ of the total blood volume from the right carotid artery over an interval of 30 min,and 1 h later the animals were resuscitated by infusion of the shed blood via the left jugular vein over 30 min.SP and SP+ATR groups were exposed to 2.4％ sevoflurane for 30 min starting from the onset of reinfusion.In ATR and SP+ATR groups,ATR 5 mg/kg was intravenously injected at 10 min before reinfusion.Six rats in each group were randomly sacrificed at 24 h after the end of autologous blood reinfusion,and the hippocampus was harvested for determination of the expression of Bcl-2 and Bax in hippocampal tissues (by Western blot) and degree of mPTP opening.At 72 h after the end of autologous blood reinfusion,the rest 6 rats in each group were selected and underwent Morris water maze test,and the cognitive function was evaluated.Results Compared with group S,the escape latency was significantly prolonged,the number of crossing the original platform and locomotor distance in the target quadrant were decreased,the expression of Bcl-2 was down-regulated,the expression of Bax was up-regulated,and the degree of mPTP opening was increased in group HSR (P＜0.05).Compared with group HSR,the escape latency was significantly shortened,the number of crossing the original platform and locomotor distance in the target quadrant were increased,the expression of Bcl-2 was up-regulated,the expression of Bax was down-regulated,and the degree of mPTP opening was decreased in group SP (P＜0.05),and no significant change was found in each parameter in ATR and SP+ATR groups (P＞0.05).Compared with group SP,the escape latency was significantly prolonged,the number of crossing the original platform and locomotor distance in the target quadrant were decreased,the expression of Bcl-2 was down-regulated,the expression of Bax was up-regulated,and the degree of mPTP opening was increased in group SP+ATR (P＜0.05).Conclusion The mechanism by which sevoflurane postconditioning ameliorates brain injury may be related to inhibiting mPTP opening in a rat model of HSR.
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Objective To evalute the role of phosphatidylinositol 3?kinase(PI3K)∕serine?threo?nine kinase(Akt)∕endothelial nitric oxide synthase(eNOS)signaling pathway in sevoflurane postcondi?tioning?induced attenuation of brain injury in a rat model of hemorrhagic shock and resuscitation(HSR). Methods Seventy?two pathogen?free healthy adult male Sprague?Dawleg rats, weighing 300-350 g, were divided into 4 groups(n=18 each)using a random number table: sham operation group(group S), group HSR, sevoflurane postconditioning group(group SP)and sevoflurane postconditioning plus PI3K∕Akt signaling pathway specific inhibitor wortmannin group(group SP+WT). Hemorrhagic shock was in?duced 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+WT, wortmannin 0.6 mg∕kg was administrated via the jugular vein at 30 min before establishment of the model. In SP and SP+WT groups, 2.4% sevoflurane was inhaled for 30 min starting from the onset of infusion of the shed blood. At 10 min before withdrawing blood(T0), im?mediately after the end of withdrawing blood(T1), at 30 min and 1 h after the end of withdrawing blood (T2,3)and immediately after infusion of the shed blood(T4), blood samples from the common carotid ar?tery were collected for blood gas analysis, the blood lactate concentration was recorded, and mean arterial pressure was simultaneously recorded. At 24 h after infusion of the shed blood, 6 rats were randomly select?ed from each group and sacrificed, and their brains were immediately removed for determination of cerebral infarct volume(by TTC staining), expression of hippocampal caspase?3(by immuno?histochemistry), and expression of Akt, phosphorylated Akt(p?Akt)and eNOS(by Western blot). The ratio of p?Akt∕Akt was calculated. Results Compared with group S, the mean arterial pressure was significantly decreased and the blood lactate concentration was increased at T1?3, the cerebral infarct volume was increased, and the expression of caspase?3 was up?regulated in the other three groups, and the ratio of p?Akt∕Akt was sig?nificantly increased, and eNOS expression was up?regulated in group SP(P<0.05). Compared with group HSR, the cerebral infarct volume was significantly decreased, the expression of caspase?3 was down?regula?ted, the ratio of p?Akt∕Akt was increased, and eNOS expression was up?regulated in group SP(P<0.05). Compared with group SP, the cerebral infarct volume was significantly increased, the expression of caspase?3 was up?regulated, the ratio of p?Akt∕Akt was decreased, and eNOS expression was down?regula?ted in group SP+WT(P<0.05). Conclusion PI3K∕Akt∕eNOS signaling pathway activation mediates sevoflurane postconditioning?induced attenuation of brain injury in a rat model of HSR.
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Objective To evaluate the effect of sevoflurane postconditioning on inositol-requiring enzyme 1 (IRE1) signaling pathway in the brain tissues in a rat model of hemorrhagic shock and resuscitation (HSR).Methods Sixty healthy adult male Sprague-Dawley rats,weighing 300-350 g,were divided into 5 groups (n =12 each) using a random number table:sham operation group (group Sham),group HSR,1.2％ sevoflurane postconditioning group (group SP1),2.4％ sevoflurane postconditioning group (group SP2) and 3.6％ sevoflurane postconditioning group (group SP3).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 the shed blood infused via the left jugular vein over 30 min.SP1,SP2 and SP3 groups inhaled 1.2％,2.4％ and 3.6％ sevoflurane,respectively,for 30 min starting from the beginning of infusion of the shed blood.Oxygen was inhaled for 30 min instead of sevoflurane in Sham and HSR groups.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).Arterial blood samples were obtained at T0,T1,T3 and T4 for blood gas analysis.Morris water maze test was performed at 72 h after the end of infusion of the shed blood.The animals were then sacrificed,and brains were removed for determination of the expression of caspase-3 in hippocampal CA1 region (by immunohistochemistry) and expression of IRE1 and X-box binding protein 1 (XBP1) in hippocampal tissues (by Western blot).Results Compared with group Sham,mean arterial pressure was significantly decreased at T1-3,the pH value and base excess were decreased,lactic acid concentrations were increased,the escape latency was prolonged,the frequency of crossing the original platform was decreased,and the expression of caspase-3 in hippocampal CA1 regitn and IRE1 and X BP 1 in hippocampal tissues was up-reg ulated in group HSR (P＜0.05).Compared with group HSR,the escape latency was significantly shortened,the frequency of crossing the original platform was increased,and the expression of caspase-3 in hippocampal CA1 region and IRE1 and XBP1 in hippocampal tissues was down-regulated in SP2 and SP3 groups (P＜0.05),and no significant changes were found in the parameters mentioned above in group SP1 (P＞0.05).Conclusion The mechanism by which sevoflurane postconditioning reduces brain injury may be related to activating IRE1 signaling pathway in the brain tissues in a rat model of HSR.
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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 table:sham 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.
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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 table:sham 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.