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Objective To evaluate the relationship between autophagy and apoptosis during postoperative cognitive dysfunction in aged rats.Methods One hundred and twenty healthy male Sprague-Dawley rats,aged 18 months,weighing 500-550 g,were divided into 4 groups (n =30 each) using a random number table:control group (group C),surgery group (group S),autophagy inhibitor 3-methyladenine group (group MA) and autophagy agonist rapamycin group (group R).Autophagy inhibitor 3-methvlade-nine 1 mg/kg and autophagy agonist rapamycin 2 mg/kg were injected via the caudal vein in MA and R groups,respectively,while the equal volume of normal saline was given instead in group S.Exploratory laparotomy was performed under anesthesia with 3％ sevoflurane 30 min later in S,MA and R groups.Ten rats of each group were selected on 1 day before operation and 3 and 7 days after operation,and Morris water maze test was performed to assess cognitive function.Then the rats were sacrificed,brains were removed and hippocampal tissues were obtained for detection of apoptosis in hippocampal neurons and the expression of microtubule-associated protein 1 light chain 3 Ⅱ (LC3 Ⅱ) and Beclin-1 by Western blot.The apoptotic rate was calculated.Results Compared with group C,the escape latency was significantly prolonged,the frequency of crossing the original platform was decreased,the apoptotic rate was increased,and the expression of LC3Ⅱ and Beclin-1 was down-regulated on 3 and 7 days after operation in S,MA and R groups (P＜0.05).Compared with group S,the escape latency was significantly prolonged,the frequency of crossing the original platform was decreased,the apoptotic rate was increased,and the expression of LC3 Ⅱ and Beclin-1 was down-regulated in group MA,and the escape latency was significantly shortened,the frequency of crossing the original platform was increased,the apoptotic rate was decreased,and the expression of LC3Ⅱ and Beclin-1 was up-regulated in group R (P＜0.05).Conclusion The mechanism of postoperative cognitive dysfunction is related to inhibiting autophagy and promoting apoptosis in hippocampal neurons of aged rats.
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Objective To evaluate the effect of remifentanil on Toll-like receptor 2 (TLR2) mRNA expression during renal ischemia-reperfusion (Ⅰ/R) in rats.Methods Fifty-four male Sprague-Dawley rats,weighing 200-250 g,were randomly divided into 3 groups (n=18 each) using a random number table:sham operation group (group S),Ⅰ/R group and remifentanil group (group R).Renal Ⅰ/R injury was produced by clamping the bilateral renal arteries for 45 min followed by reperfusion in Ⅰ/R and R groups.Bilateral renal arteries were only exposed but not clamped in group S.Remifentanil 1.0 μg · kg-1 · min-1 was infused via the tail vein starting from 15 min before ischemia until 30 min of reperfusion in group R,while the equal volume of normal saline was given instead in S and Ⅰ/R groups.The animals were sacrificed at 15 min before ischemia and 6 and 24 h of reperfusion,and the renal specimens were obtained for examination of the pathological changes (with light microscope) and for determination of the contents of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) (by ELISA) and expression of TLR2 mRNA (by RT-PCR) and cell apoptosis (by double staining and flow eytometry).The apoptotic rate was calculated.Results Compared with group S,TLR2 mRNA expression was significantly up-regulated,and the contents of TNF-α and IL-6 and apoptotic rate were increased at 6 and 24 h of reperfusion in Ⅰ/R and R groups.Compared with group Ⅰ/R,TLR2 mRNA expression was significantly down-regulated,and the contents of TNF-α and IL-6 and apoptotic rate were decreased at 6 and 24 h of reperfusion in group R.The pathological changes were significantly attenuated in group R as compared with group Ⅰ/R.Conclusion The mechanism by which remifentanil reduces renal Ⅰ/R injury is related to down-regulation of TLR2 expression and decrease in TLR2 activity and inhibition of inflammatory responses in renal tissues and cell apoptosis in rats.
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Objective To evaluate the role of calpain in sevoflurane anesthesia-induced apoptosis in hippocampal neurons of aged rats.Methods Fifty-four healthy female Sprague-Dawley rats,aged 18 months,weighing 450-550 g,were randomly divided into 3 groups (n=12 each) using a random number table:control group (group C),sevoflurane group (Sev group) and calpain inhibitor M DL28170 group (group M).In group C,the rats inhaled 50％ O2-50％N2 for 3 h.In Sev group,the rats inhaled 3％ sevoflurane for 3 h.In group M,MDL28170 10 mg/kg was injected via the tail vein,30 min later 3％ sevoflurane was inhaled for 3 h,and MDL28170 was simultaneously infused at 3.33 mg · kg 1 · h-1 via the tail vein.Nine rats in each group were selected,and cognitive function was assessed by using Morris water maze test at 30 min before anesthesia and 1-5 days after anesthesia.The escape latency and frequency of crossing the original platform were recorded.After the end of Morris water maze test performed at 30 min before anesthesia and 1-5 days after anesthesia,3 rats in each group were sacrificed,and hippocampal tissues were obtained for detection of cell apoptosis (by flow cytometry) and intracellular [Ca2+] i.Apoptotic rate was calculated.Results Compared with group C,the escape latency was significantly prolonged,and the frequency of crossing the original platform was decreased,and the apoptotic rate and intracellular [Ca2+]i were increased at 1 day after anesthesia in Sev and M groups.Compared with group Sev,the escape latency was significantly shortened,the frequency of crossing the original platform was increased,and the apoptotic rate was decreased at 1 day after anesthesia,and no significant change was found in intracellular [Ca2+]i in group M.Conclusion Calpain activation is involved in sevoflurane anesthesia-induced apoptosis in hippocampal neurons of aged rats.
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Objective To evaluate the effects of the prone position on pulmonary gas exchange during mechanical ventilation under general anesthesia.Methods Thirty patients scheduled for elective spine surgery in the prone position under general anesthesia (group prone,n =30),30 patients scheduled for elective spine surgery in the supine position under general anesthesia (group supine,n=30),aged 30-64 yr,with body mass index of 19-30 kg/m2,of ASA physical status Ⅰ or Ⅱ,were enrolled in the study.After induction of general anesthesia,the patients were mechanically ventilated.Anesthesia was maintained with total intravenous anesthesia.At 10 min before pre-oxygenation (T0),10 min after intubation (immediately after the patients were moved from the supine to the prone position) (T1),45 and 90 min after intubation (T2,3),5 min before extubation (immediately before supine position to the prone position) (T4),and 15 min after extubation (T5),arterial blood samples were taken for blood gas analysis,and PaO2 and PaCO2 were recorded.Alveolar-arterial oxygen difference (A-aDO2) was calculated.Digital radiography was performed and the changes of the lung were observed.Results Compared with supine group,PaO2 was significantly increased and A-aDO2 was decreased at T1-4 in prone group.There was no significant difference in PaCO2,and PaO2 and A-aDO2 at T0 and T5 between the two groups.The results of digital radiography showed no atelectasis at different time points in either group.Conclusion Pulmonary gas exchange in the prone position is superior to that in the supine position during mechanical ventilationunder general anesthesia.
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Objective To evaluate the effect of preconditioning with nimodipine on postoperative cognitive dys function of aged rats.Methods Ninety healthy male Sprague-Dawley rats,aged 18 months,weighing 400-500 g,were randomly divided into 3 groups (n =30 each) using a random number table:nimodipine control group (group N),surgery group (group S),and nimodipine + surgery group (N+ S group).In N and N + S groups,nimodipine 1 mg/kg was intraperitoneally injected,while the equal volume of normal saline was given instead in S group.30 min later,group N inhaled pure oxygen for 2 h,and S and N + S groups inhaled 1.8 ％ isoflourane for 2 h when splenectomy was performed.Morris water maze test was performed on 1 day before operation and 1st,3rd and 7th days after operation.After the end of Morris water maze test at 1 day before operation and 1st and 7th days after operation,10 rats were sacrificed and brains were removed and hippocampi were isolated for determination of apoptosis in hippocampal neurons,intracellular [Ca2+] i in cytoplasm,and hippocampal Bcl-2 and Bax mRNA expression and for examination of ultrastructure of hippocampal neurons.Results Compared with the value before administration,the escape latency was significantly prolonged,the frequency of crossing the original platform was decreased,apoptotic rate and [Ca2+]i were increased,Bcl-2 mRNA expression was down-regulated,and Bax mRNA expression and Bax/Bcl-2 mRNA ratio were up-regulated at each time point after operation in S and N + S groups,and no significant changes were found in the parameters mentioned above in N group.Compared with group S,the escape latency was significantly shortened,the frequency of crossing the original platform was inecreased,apoptotic rate and [Ca2+]i were decreased,Bcl-2 mRNA expression was up-regulated,and Bax mRNA expression was down-regulated at each time point after operation in group N + S.Pathological changes were found in S and N + S groups and the damage was severer in S group than in N + S group.Conclusion Nimodepine preconditioning can prevent postoperative cognitive dysfunction of aged rats,and inhibition of calcium overloadinduced apoptosis in hippocampal neurons may be involved in the mechanism.
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Objective To evaluate the role of mitochondria-mediated apoptosis in hippocampal neurons in sevoflurane anesthesia-induced cognitive dysfunction in aged rats.Methods Sixty healthy male Sprague-Dawley rats,aged 20 months,weighing 550-600 g,were randomly divided into 2 groups (n =30 each) using a random number table:control group (group C) and sevoflurane anesthesia group (group S).Animals inhaled pure oxygen and 3 ％ sevoflurane for 4 h in C and S groups,respectively.Ten rats were chosen at 1 and 6 days after anesthesia and hippocampal tissues were obtained for detection of cell apoptosis and mitochondrial membrane potential (MMP) (using flow cytometry) and expression of cytochrome c (Cyt c) in cytoplasm and activated caspase-3 in hippocampal neurons (by Western blot).The apoptotic rate was calculated.Results Compared with group C,the escape latency was significantly prolonged,the frequency of crossing the original platform,the percentage of time of staying at the original platform quadrant and MMP were decreased,the apoptotic rate was increased,and the expression of activated caspase-3 and Cyt c in cytoplasm was up-regulated in.group S.Conclusion The mechanism by which sevoflurane anesthesia induces cognitive dysfunction is related to the activation of mitochondria-mediated apoptosis in hippocampal neurons of aged rats.