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Objective:To evaluate the role of hippocampal REV-ERBα in postoperative cognitive dysfunction in rats.Methods:Thirty-two SPF healthy male Sprague-Dawley rats, aged 12-14 weeks, weighing 360-380 g, were divided into 4 groups ( n=8 each) using a random number table method: control group (group C), surgery group (group S), surgery + dimethyl sulfoxide (DMSO) group (group SD), and surgery + SR9009 group (group SS). Exploratory laparotomy was performed under sevoflurane anesthesia in S, SD and SS groups.Normal saline containing 0.1% DMSO was injected into hippocampal CA1 area at 1 h before laparotomy, with 2 μl on each side in group SD, and REV-ERBα agonist SR9009 (in normal saline containing 0.1% DMSO) was injected into hippocampal CA1 area at 1 h before laparotomy, with 2 μl on each side in group S+ SR9009.Morris water maze test was performed at 1 and 3 days after operation.Rats were sacrificed at 1 h after the end of Morris water maze test on day 3 after surgery, and the hippocampal tissues were obtained for determination of the expression of REV-ERBα, Brain and Muscle ARNT-Like 1 (BMAL1) protein, synaptophysin (SYN), postsynaptic density (PSD)-95 protein and N-methyl-D-aspartate receptor 2B subunit (GRIN2B) (by Western blot) and microscopic examination of the morphology of hippocampal neurons and Nissl bodies (by Nissl staining), and the viable neurons were counted. Results:Compared with group C, the percentage of time of staying at the target quadrant was significantly decreased, and the number of crossing platform was reduced on days 1 and 3 after exploratory laparotomy, the expression of REV-ERBα, BMAL1, PSD95, SYN and GRIN2B was down-regulated, and the number of viable neurons was decreased in group S and group SD ( P<0.05). Compared with group S and group SD, the percentage of time of staying at the target quadrant and the number of crossing platform were significantly increased on days 1 and 3 after exploratory laparotomy, the expression of REV-ERBα and PSD95 was up-regulated, the number of viable neurons was increased ( P<0.05), and no significant change was found in the expression of BMAL1, SYN and GRIN2B in group SS ( P>0.05). There was no significant difference in the indexes mentioned above between group S and group SD ( P>0.05). Conclusions:Activation of REV-ERBα can improve postoperative cognitive dysfunction, and the mechanism may be related to up-regulation of PSD95 expression in hippocampus and reduction of neuronal damage in rats.
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Objective:To evaluate the role of hippocampal histone deacetylases (HDACs) in perioperative neurocognitive disorders (PND) and the relationship with postsynaptic dense protein 95 (PSD95) in rats.Methods:Sixty clean-grade healthy male Sprague-Dawley rats, aged 10-14 weeks, weighing 250-280 g, were divided into 3 groups ( n=20 each) using a random number table method: control group (group C), surgery group (group S) and HDAC inhibitor MS-275 group (group MS-275). Exploratory laparotomy was performed under 3% sevoflurane anesthesia in group S. MS-275 10 mg/kg was intraperitoneally injected at 0.5 h before exploratory laparotomy in group MS-275.Morris water maze tests were performed on 1 day before surgery and 1, 3 and 7 days after surgery.Ten rats were sacrificed on 1 day after surgery, and hippocampal tissues were obtained for determination of the expression of HDAC1-3 and PSD95 protein and mRNA by Western blot and real-time polymerase chain reaction, respectively.The density of hippocampal neurons was determined by the Nissl staining. Results:Compared with group C, the postoperative escape latency was significantly prolonged, the number of crossing the original platform was decreased, the density of hippocampal neurons was decreased, the expression of HDAC2 protein and mRNA was up-regulated, and the expression of PSD95 protein and mRNA was down-regulated in group S ( P<0.05 or 0.01). Compared with group S, the postoperative escape latency was significantly shortened, the number of crossing the original platform was increased, the density of hippocampal neurons was increased, the expression of HDAC2 protein and mRNA was down-regulated, and the expression of PSD95 protein and mRNA was up-regulated in group MS-275 ( P<0.05 or 0.01). There was no significant difference in the expression of HDAC1 and HDAC3 protein and mRNA among the three groups ( P>0.05). Conclusion:HDAC2 is involved in the pathophysiological mechanism of PND by down-regulating the expression of PSD95 in rats.
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Objective@#To investigate the role of clock gene Bmal1, Per2 and Egr1 expression in learning and memory undergoing sevoflurane anesthesia after acute sleep deprivation.@*Methods@#72 male SD rats were equally divided into four groups using a random number table (n=18) : normal control group (group Control), do not do any processing; sleep deprivation group (group SD), acute sleep deprivation for 96 h; sevoflurane group (group Sev), suffering 2.5% sevoflurane for 3 h; sleep deprivation+sevoflurane group (group SD+Sev), 96 h sleep deprivation followed by 3 h 2.5% sevoflurane inhalation. The Morris water maze, for spatial memory acquisition test, was used to measure the time percent of target quadrant and numbers of platform-site crossovers before sleep deprivation (T0) and at 1 d (T1), 3 d (T2), 7 d (T3) after inhalation anesthesia. Rats were sacrificed after spatial memory acquisition test. Brain hippocampus samples were obtained for determination of Bmal1, Per2 and Egr1 expression by Western blot, and neuron morphology was observed by the Nissl staining.@*Results@#Compared with Control group, the percentage of time in target quadrant and the numbers of platform-site crossovers were significantly decreased at T1 and T2 in Sev group (P<0.05); and compared with Control group, the percentage of time in target quadrant and the numbers of platform-site crossovers were also significantly decreased at T1, T2 and T3 in SD group rats (P<0.05). Compared with Sev group rats (the percentages of time in target quadrant: T1: (32.37±1.36)%; T2: (30.91±1.26)%; T3: (33.78±2.20)%; the numbers of platform-site crossovers: T1: (4.55±0.39); T2: (3.11±0.37); T3: (3.95±0.34)), the percentages of time in target quadrant (T1: (27.20±1.42)%; T2: (28.19±1.04)%; T3: (30.06±1.22)%) and the numbers of platform-site crossovers (T1: (3.11±0.46); T2: (3.30±0.38); T3: ( 3.20±0.39)) in SD+Sev group rats were significantly decreased at T1, T2 and T3 (all P<0.05). Compared with control group, the levels of hippocampal proteins Bmal1, Per2 and Egr1 were significantly reduced at T1 in Sev group (P<0.05). Compared with control group, the level of hippocampal protein Per2 was significantly increased, but the levels of hippocampal proteins Bmal1 and Egr1 were significantly decreased at T1 and T2 in SD group (P<0.01). Compared with Sev group, the levels of hippocampal proteins Bmal1 and Egr1 were significantly reduced at T1, T2 and T3 in SD+Sev group (P<0.01), and the protein level of hippocampal Per2 was significantly decreased at T1, but then increased at T2 and T3 in SD+Sev group (P<0.01). The hippocampal Nissl staining in CA1 at T2 revealed that there were irregular distribution of pyramidal neurons existed in Sev group, and vacuolar degeneration with vague outlines of pyramidal neurons in SD group, while pyramidal neuron atrophy and few number of Nissl bodies, compared with control group, were observed in SD+Sev group.@*Conclusion@#Acute sleep deprivation following with sevoflurane anesthesia resulted in hippocampal memory impairment, which was associated with abnormal expression of hippocampal Bmal1, Per2 and Egr1.
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Objective To evaluate the role of autophagy in cerebral ischemia-reperfusion (I/R) injury in diabetic mice and the relationship with histone deacetylase 3 (HDAC3)/Bmal1 signaling pathway.Methods Healthy clean-grade male C57BL/6 mice were used in the study.Diabetes mellitus was induced by intraperitoneal injection of streptozotocin.Thirty-six mice with diabetes mellitus after being fed for 8 weeks were divided into 3 groups (n =12 each) using a random number table method:sham operation group (group S),I/R group and I/R plus HDAC3 inhibitor group (group I/R-H).Cerebral I/R was induced by middle cerebral artery occlusion for 1 h,followed by 24-h reperfusion in anesthetized mice.Specific HDAC3 inhibitor RGFP966 10 mg/kg was subcutaneously injected at 30 min before establishing the model in group I/R-H.Brain tissues were obtained at 24 h of reperfusion for microscopic examination and for determination of cerebral infarct size (by TTC),cell apoptosis (by TUNEL),activities of superoxide dismutase (SOD) and reactive oxygen species (ROS) and malondialdehyde (MDA) content (by colorimetric assay),expression of autophagy-related protein Beclin-1 and LC3B (by immunofluorescence),and expression of HDAC3,Bmal1,GSK-3β and p62 (by Western blot).Apoptosis index (AI) was calculated.Results Compared with group S,the cerebral infarct size was significantly increased,the activities of SOD and ROS and content of MDA in brain tissues were decreased,the expression of Bmal1,p-GSK-3β and HDAC3 was down-regulated,and AI was increased in group I/R (P＜0.05).Compared with group I/ R,the cerebral infarct size was significantly increased,the activities of SOD and ROS and content of MDA in brain tissues were increased,the expression of Bmall,p-GSK-3β,Beclin-1 and LC3B was up-regulated,AI was decreased,and the expression of HDAC3 and p62 was down-regulated in group I/R-H (P＜ 0.05).Conclusion HDAC3/Bmal1 signaling pathway exerts endogenous protective effect through activating autophagy and increasing the antioxidant capacity following cerebral I/R in diabetic mice.
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Objective To evaluate the relationship between the mechanism of silent information regulator factor 2-related enzyme 1 (SIRT1)-mediated mitophagy in the myocardium and mitofusin 2 (Mfn2) in diabetic rats.Methods Twenty-four SPF healthy adult male Sprague-Dawley rats,weighing 210-220 g,were allocated into 3 groups (n =8 each) using a random number table:control group (group C),diabetes mellitus group (group DM) and diabetes mellitus plus SIRT1 activator SRT1720 group (group DM+SRT).Diabetes mellitus was induced by intraperitoneal 1％ streptozotocin 60 mg/kg and confirmed by blood glucose ≥ 16.7 mmol/L 3 days later.SRT1720 1 mg/kg was injected via the caudal vein for 7 consecutive days in group DM+SRT.The ultrasonic method was used to measure the parameters of heart function including left ventricular end-diastolic volume (LVEDV),left ventricular end-systolic volume (LVESV),left ventricular ejection fraction (LVEF),heart rate (HR),E wave velocity (E),A wave velocity (A) and E/A ratio.Myocardial specimens were obtained for determination of the interaction between SIRT1 and Mfn2 and acetylation of Mfn2 (by co-immuno-precipitation) and expression of SIRT1,Mfn2,microtubule-associated protein 1 light chain 3 Ⅱ (LC3 Ⅱ),LC3 Ⅰ,Beclin1 and P62 (by Western blot).The ratio LC3 Ⅱ to LC3 Ⅰ (LC3 Ⅱ / Ⅰ ratio) was calculated.Results Compared with group C,LVEDV,LVEF,HR,E and E/A ratio were significantly decreased,A was increased,LC3 Ⅱ / Ⅰ ratio was decreased,the expression of Beclin1,SIRT1 and Mfn2 was down-regulated,the expression of P62 was up-regulated,and the interaction between SIRT1 and Mfn2 was decreased in group DM (P＜0.05).Compared with group DM,LVEDV,LVEF,E and E/A ratio were significantly increased,A was decreased,LC3 Ⅱ / Ⅰ ratio was increased,the expression of Beclin1 and SIRT1 was up-regulated,the expression of P62 was down-regulated,the interaction between SIRT1 and Mfn2 was increased,and the acetylation of Mfn2 was decreased in group DM+SRT (P＜0.05).Conclusion The mechanism by which SIRT1 mediates mitophagy in the myocardium is related to SIRT1-induced deacetylation of Mfn2 in diabetic rats.
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Objective To evaluate the effects of sevoflurane on the expression of early growth response gene 1 (Egr-1) and Egr-2 in the suprachiasmatic nuclei (SCN) of sleep-deprived rats.Methods Forty-eight pathogen-free healthy male Sprague-Dawley rats,were divided into 4 groups (n =12 each) using a random number table:control group (group C),sleep deprivation group (group SD),sevoflurane group (group SEV) and sleep deprivation plus sevoflurane group (group SD+SEV).The rats were subjected to sleep deprivation for 96 h in group SD.The rats inhaled 2.5％ sevoflurane for 3 h in group SEV.The rats inhaled 2.5％ sevoflurane for 3 h after being subjected to sleep deprivation for 96 h in group SD+SEV.The mechanical paw withdrawal threshold (MWT) was measured at 12 h,3 days and 7 days after emergence from anesthesia (T1-3).The animals were sacrificed after blood samples were obtained from the external carotid artery,and the cerebral SCN was removed for determination of Egr-1 and Egr-2 expression by Western blot.Results Compared with group C,the MWT was significantly decreased at T1-3 in SD,SEV and SD+SEV groups,the expression of Egr-1 and Egr-2 in SCN was significantly up-regulated at T1-3 in SD and SD+SEV groups,and the expression of Egr-1 in SCN was significantly up-regulated at T1-3,and the expression of Egr-2 in SCN was up-regulated at T1 in group SEV (P＜0.05).Compared with SD and SEV groups,the MWT was significantly decreased at T1-3 in group SD+SEV,and the expression of Egr-1 and Egr-2 in SCN was significantly up-regulated at T1-3 in group SD+SEV (P＜0.05).Conclusion The mechanism by which sevoflurane aggravates hyperalgesia is related to up-regulation of Egr-1 and Egr-2 expression in SCN of sleepdeprived rats.
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Objective To investigate the effect of dexmedetomidine hydrochloride ( Dex ) preconditioning on renal function in rats after renal ischemia reperfusion injury under high glucose condition. Methods SD rats were randomly divided into 6 groups:NG-Sham operated group,NG-I/R group, NG-Dex group,HG-Sham operated group,HG-I/R group,HG-Dex group. Renal ischemia reperfusion model was established except Sham groups. Dex 50 μg·kg-1 was injected intraperitoneally 30 min before ischemia in the Dex preconditioning group,25% glucose 3 g·kg-1 was given intraperitoneally before the renal ischemia reperfusion model was established in high glucose groups. Blood glucose and renal function of each group were detected . Renal pathologic changes were observed with hematoxylin-eosin staining. Apoptosis of renal tissue was detected by TUNEL method. Results BUN,Cr and apoptosis rate in NG-I/R group were higher than those in NG-Sham operated group ( P<0.05);BUN,Cr and apoptosis rate in NG-Dex group were lower than those in NG-I/R group ( P<0.05);BUN,Cr and apoptosis rate in HG-I/R group and HG-Dex group were higher than those in NG-I/R group and NG-Dex group,respectively (P<0.05); However,there was no significant difference between HG-I/R group and HG-Dex group ( P>0.05) . Conclusion Dex has a protective effect on renal function after renal ischemia reperfusion, but this effect is inhibited in high glucose condition, which may relate to the increasing of kidney cells apoptosis.
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Objective To evaluate the effect of dexmedetomidine on spinal purinergic receptor 2X-4 (P2X4)/nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) pathway in a rat model of diabetic neuropathic pain (DNP).Methods Twenty-four pathogenfree adult male Sprague-Dawley rats,weighing 200-220 g,aged 8 weeks,were allocated into 3 groups (n =8 each) using a random number table:control group (C group),DNP group and DNP plus dexmedetomidine group (DNP+D group).Diabetes mellitus was induced by intraperitoneal 1％ streptozotocin 60 mg/kg and confirmed by blood glucose ≥ 16.7 mmol/L 3 days later.In group DNP+D,dexmedetomidine 50 μg/kg was intraperitoneally injected once a day for 6 consecutive weeks starting from 3 days after the model was successfully established.The mechanical paw withdrawal threshold (MWT) and sciatic nerve conduction velocity (SNCV) were measured at 2,4 and 6 weeks after injection of dexmedetomidine.The rats were sacrificed at 6 weeks after injection of dexmedetomidine,and the L4-6 segments of the spinal cord were removed for examination of the pathological changes (with a light microscope) and for determination of P2X4,NLRP3 and interleukin-lbeta (IL-1β3) expression (by Western blot).The sural nerve was obtained for examination of the ultrastructure by electron microscopy.Results Compared with group C,the MWT was significantly decreased at 2,4 and 6 weeks after injection of dexmedetomidine,the SNCV was decreased at 6 weeks after injection of dexmedetomidine,the expression of P2X4,NLRP3 and IL-1β in the spinal cord was up-regulated (P＜0.05),and the pathological changes of the spinal cord and sural nerve were marked in DNP and DNP+D groups.Compared with group DNP,the MWT was significantly increased at 2,4 and 6 weeks after injection of dexmedetomidine,the SNCV was increased at 6 weeks after injection of dexmedetomidine,the expression of P2X4,NLRP3 and IL-1β in the spinal cord was down-regulated (P＜0.05),and the pathological changes of the spinal cord and sural nerve were significantly attenuated in group DNP+D.Conclusion The mechanism by which dexmedetomidine mitigates DNP is probably related to inhibition of P2X4/NLRP3 pathway in rats.
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Objective To investigate the effect of dexmedetomidine hydrochloride ( Dex ) preconditioning on renal function in rats after renal ischemia reperfusion injury under high glucose condition. Methods SD rats were randomly divided into 6 groups:NG-Sham operated group,NG-I/R group, NG-Dex group,HG-Sham operated group,HG-I/R group,HG-Dex group. Renal ischemia reperfusion model was established except Sham groups. Dex 50 μg·kg-1 was injected intraperitoneally 30 min before ischemia in the Dex preconditioning group,25% glucose 3 g·kg-1 was given intraperitoneally before the renal ischemia reperfusion model was established in high glucose groups. Blood glucose and renal function of each group were detected . Renal pathologic changes were observed with hematoxylin-eosin staining. Apoptosis of renal tissue was detected by TUNEL method. Results BUN,Cr and apoptosis rate in NG-I/R group were higher than those in NG-Sham operated group ( P<0.05);BUN,Cr and apoptosis rate in NG-Dex group were lower than those in NG-I/R group ( P<0.05);BUN,Cr and apoptosis rate in HG-I/R group and HG-Dex group were higher than those in NG-I/R group and NG-Dex group,respectively (P<0.05); However,there was no significant difference between HG-I/R group and HG-Dex group ( P>0.05) . Conclusion Dex has a protective effect on renal function after renal ischemia reperfusion, but this effect is inhibited in high glucose condition, which may relate to the increasing of kidney cells apoptosis.
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Objective To investigate the effects of different duration of sevoflurane anesthesia in the neonatal period on the long?term cognitive function and hippocampal synaptic plasticity in rats. Methods Twenty?four pathogen?free healthy Sprague?Dawley rats of both sexes, aged 7 days, weighing 12-16 g, were divided into 3 groups ( n=8 each) using a random number table: control group ( group C) , sevoflu?rane anesthesia for 2 h group ( group S1 ) , and sevoflurane anesthesia for 6 h group ( group S2 ) . Group S1 and group S2 inhaled 2% sevoflurane for 2 and 6 h, respectively. Morris water maze test was performed at 30 days after the end of anesthesia ( postnatal day 37) to assess the cognitive function. After the end of the test, the rats were sacrificed, and hippocampi were isolated for determination of the expression of brain?de?rived neurotrophic factor ( BDNF) , postsynaptic density?95 ( PSD?95) and synapsin 1 in hippocampal tis?sues by Western blot. Results Compared with group C, the escape latency on 4th and 5th days of the test in group S1 and on 2nd-5th days of the test in group S2 was significantly prolonged, and the frequency of crossing the original platform was significantly decreased, and the time of staying at the platform quadrant was significantly shortened in S1 and S2 groups, the expression of BDNF, PSD?95 and synapsin 1 in hipp?ocampal tissues was significantly down?regulated in group S2 (P0?05) . Compared with group S1 , no significant change was found in the escape latency and frequency of crossing the original platform (P>0?05), the time of staying at the platform quadrant was significantly shortened, and the expression of BDNF, PSD?95 and synapsin 1 in hippocampal tissues was significantly down?regula?ted in group S2 ( P<0?05) . Conclusion Short?time and long?time sevoflurane anesthesia both can induce long?term cognitive dysfunction in the neonatal period, and the severity is aggravated with prolonged anes?thesia; the partial mechanism is related to inhibition of the synaptic plasticity of hippocampal neurons of rats.
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Objective To observe analgesia effect of morphine hydrochloride and hydromorphone hydrochloride in patients after transurethral resection of prostate. Methods Patients after transurethral resection of the prostate (TURP) were randomly divided into 2 groups, morphine hydrochloride group (n=45) and hydromorphone hydrochloride group (n=47). Analgesia, sedation efficacy and adverse reactions were evaluated at 6 and 24 h after they received epidural postoperative analgesia by using VAS score and Ramsay score. Results In 6 h, hydromorphone hydrochloride group had a better pain tolerance and feeling than morphine hydrochloride group (P0.05).There were no differences in adverse reactions between the two groups ( P>0. 05 ) . Conclusion Hydromorphone has a better effect than morphine in epidural analgesia in 6 h.
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Objective To evaluate the effects of Janus kinase 2/signal transducers and activators of transcription 3 (JAK2/STAT3) signaling pathway on the brain injury induced by myocardial ischemia-reperfusion (I/R) in diabetic rats.Methods Pathogen-free male Sprague-Dawley rats,weighing 200-220 g,were used in this study.Diabetes mellitus was induced by intraperitoneal 1％ streptozotocin 60 mg/kg and confirmed by blood glucose level ≥ 16.7 mmol/L 3 days later.Twenty-four rats with diabetes mellitus were randomly allocated into 3 groups (n =8 each) using a random number table:sham operation group (group S),I/R group,and myocardial I/R + AG490 (JAK inhibitor) group (group ⅠA).Myocardial I/R was induced by occlusion of the anterior descending branch of the left coronary artery for 30 min,followed by 120 min of reperfusion in the rats anesthetized with pentobarbital sodium.AG490 3 mg/kg was injected intravenously at 20 min before reperfusion in group IA.The rats were sacrificed at 120 min of reperfusion,and the brains were removed for determination of caspase-3 and nuclear factor kappa B (NF-κB) activities (using colorimetric method),cell apoptosis (by TUNEL),and expression of interleukin-1 (IL-1),IL-6,IL-8,Bax,Bcl-2,cytochrome C (Cyt c),phosphorylated JAK2 (p-JAK2),and phosphorylated STAT3 (p-STAT3) (by Western blot).Apoptosis index was calculated.Results Compared with group S,the expression of Bax,Cyt c,IL-1,IL-6,IL-8,p-JAK2 and p-STAT3 was significantly up-regulated,the expression of Bcl-2 was down-regulated,and NF-κB and caspase-3 activities and apoptosis index were increased in I/R and IA groups (P＜0.05).Compared with group I/R,the expression of Bax,Cyt c,IL-1,IL-6,IL-8,p-JAK2 and p-STAT3 was significantly down-regulated,the expression of Bcl-2 was up-regulated,and NF-κB and caspase-3 activities and apoptosis index were decreased in group IA (P＜0.05).Conclusion Inflammatory responses mediated by JAK2/STAT3 signaling pathway are involved in the brain injury induced by myocardial I/R in diabetic rats.
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Objective To systematically review the efficacy of bispectral index (BIS) monitoring for prevention of intraoperative awareness in patients under general anesthesia.Methods The Cochrane Central Register of Controlled Trials (Central),PubMed,Medline,and EMBASE were searched for randomized controlled clinical trials involving detection of intraoperative awareness in patients in whom BIS was used or not under general anesthesia.The quality of the studies was evaluated by the method recommended by Cochrane Collaboration.Evaluation indexes included the incidence of intraoperative awareness.Meta-analysis was conducted using RevMan 5.1 software.Results Five randomized controlled clinical trials involving 34181 patients were included in this meta-analysis.There were 17432 cases in whom BIS was applied and the incidence of intraoperative awareness was 0.132％.There were 16749 cases in whom BIS was not used and the incidence of intraoperative awareness was 0.245％.There was no significant difference in the incidence of intraoperative awareness between the two groups (P ＞0.05).Further analysis was performed according to the method of anesthesia.In inhalational anesthesia,there were 13288 cases in whom BIS was applied and the incidence of intraoperative awareness was 0.128％,and there were 13202 cases in whom BIS was not applied and the incidence of intraoperative awareness was 0.113％.There was no significant difference in the incidence of intraoperative awareness between the two groups (P ＞ 0.05).In total intravenous anesthesia,there were 4144 cases in whom BIS was applied and the incidence of intraoperative awareness was 0.145％,and there were 3547 cases in whom BIS was not applied and the incidence of intraoperative awareness was 0.733 ％.The incidence of intraoperative awareness was significantly lower in the patients in whom BIS was applied than those in whom BIS was not applied (P ＜ 0.01).Conclusion BIS monitoring can effectively prevent the development of intraoperative awareness in patients under total intravenous anesthesia,but can not prevent the development of intraoperative awareness in patients under inhalational anesthesia.
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Objective To investigate the effect of ischemic post-conditioning (IPO) on the level of Heme oxygenase-1 (HO-1) in acute ischemia - reperfusion (I/R) injury of lung in order to illuminate its protective mechanism.Methods Forty-eight adult SD rats were randomly divided (random number) into 6groups ( n =8 each):sham operation group ( S group) ; I/R group in which the hilum of left lung was clamped for 45 min followed by 105 min reperfusion; IPO group in which left lung hilum was clamped for 45min and post - conditioned by alternation of 30 s reperfusion with 30 s re-occlusion for three times before perfect perfusion for 102 min; Hemin (HM) + I/R group; ZnPPⅨ (zinc protoporphyrin Ⅸ) + IPO group and HM + S group.Arterial partial pressure of oxygen ( PaO2 ) and malondialdehyde (MDA) content in blood serum were assayed.The left lung was removed for determination of wet/dry (W/D) lung weight ratio and level of HO-1 protein was detected by immunohistochemical technique and pathohistological changes were observed under light microscopic examination. Comparisons among multiple groups were studied by using one-way analysis of variance (ANOVA). Statistical comparisons within groups were analyzed by using paired t -test.Results The level of HO-1 in lung tissue was significantly increased in the I/R group compared with the S group and the HM + S group (P ＜0.01,P ＜0.05).Compared to the I/R group,the IPO and the HM + I/R groups had significant higher level of HO-1 ( P ＜ 0.05,P ＜ 0.01 ).The PaO2 was significantly lower in all experimental groups than that in the S group (90 ± 11 ) mmHg.However,the values of PaO2 in the IPO and the HM + I/R groups were higher than that in the I/R group (P ＜ 0.01 ).In addition to severe lung tissue damage evidenced by pathohistological changes,the lung wet/dry (W/D) weight ratio and MDA level in blood serum were significantly higher in the I/R group than those in the S group (P ＜0.01 ),whereas the lung damage was attenuated either by IPO or by HM pretreatment (P ＜ 0.05,IPO or HM + I/R vs.I/R).Conclusions IPO can attenuate the lung ischemia - reperfusion injury through upregulating the level of HO-1 protein and inhibiting lipid peroxidation injury.
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Objective To investigatc the role of phosphatidylinositol 3-kinase (PI3K)/protein-serine-threonine kinases (Akt) signal pathway in ginsenoside Rb1 pretreatment-induced attenuation of myocardial ischemiareperfusion (I/R) injury in diabetic rats.Methods Male SD rats weighing 250-300 g were used in this study.Diabetes mellitus was induced by intraperitoneal streptozotocin and confirmed by fasting blood glucose ≥ 16.7mmol/L.Eight weeks after diabetes mellitus was induced,48 rats were randomly divided into 4 groups ( n =12each):group myocardial I/R (group I/R); group ginsenoside Rb1 (group R); group ginsenoside Rb1 + wortmannin (PI3K inhibitor) (group RW) and group wortmannin (group W).Myocardial I/R was induced by occlusion of anterior descending branch of left coronary artery for 30 min followed by 120 min reperfusion.Ginsenoside Rb1 40 mg/kg was injected iv at 10 min before ischemia in groups R and RW,while in groups RW and W wortmannin 15 μg/kg was injected iv at 20 min before ischemia.Arterial blood samples were collected at the end of 120 min reperfusion for determination of creatine kinase (CK) and lactate dehydrogenase (LDH) activities.The rats were then sacrificed.The infarct size was measured by tetrazolium method.Myocardial apoptosis was detected by TUNEL and apoptotic index (the number of apoptotic myocardial cells/the total number of myocardial cells) was calculated.The expression of Akt and phosphorylated Akt (p-Akt) was determined by Western blotting.Results Ginsenoside Rb1 pretreatment significantly reduced the infarct size,myocardial cell apoptotic index and serum CK and LDH activities and up-regulated p-Akt expression in group R as compared with group I/R.The protective effects of ginsenoside Rbl against myocardial I/R injury were significantly attenuated by wortmannin pretreatment in group RW compared with group R.Conclusion PI3K/Akt signal pathway is involved in the protective effects of ginsenoside Rb1 against myocardial I/R injury in diabetic rats.
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Objective To investigate the analgesic efficacy and spinal neurotoxicity of intrathecal (IT) different doses of dexmedetomidine in rats. Methods Sixty male SD rats weighing 180-220 g were randomly divided into 5 groups ( n = 12 each): groupnormal control (group C); group IT normal saline (group N); different doses of dexmedetomidine groups received IT dexmedetomidine 0.75, 1.50 and 3.00 μg/kg respectively (groups D1.3). Paw withdrawal threshold to mechanical stimulation (PWMT)with yon Frey filaments and tail flick latency (TFL) to a thermal nociceptive stimulus were measured before (To, baseline) and at 30 or60 rin after IT dexmedetomidine or normal saline administration (T1, T2 ) and the percentage of the maximum possible effect ( MPE ) was calculated. Lumbar segment of the spinal cord ( L4-6 ) was removed for microscopic examination and determination of c-Fos expression (by immuno-histochemistry) at 7, 24 and 48 h after IT dexmedetomidine or normal saline administration. Results PWMT, TFL and the percentage of MPE were significantly increased after IT dexmedetomidine as compared with the baseline values at T0 in groups D1-3 ( P ＜ 0.05). PWMT was significantly higher at T1 and TFL and the percentage of MPE were higher at T2 in groups D1-3 than in groups C and N,and in group D3 than in groups D1,2 ( P ＜ 0.05). At 7,24 h after IT dexmedetomidine c-Fos protein expression was significantly higher in group D3 than in groups C and N( P ＜ 0.05). There was no significant difference in c-Fos expression at 48 h after IT dexmedetomidine between group D3 and groups C and N ( P ＞ 0.05 ). At 24 h after IT dexmedetomidine c-Fos protein expression was significantly higher in group D3 than in other 4 groups( P ＜ 0.05). Slight spinal cord injury was observed at 24 h after IT dexmedetomidine in group D3. Conclusion IT dexmedetomidine has antinociceptive effect. High dose dexmedetomidine IT can produce transient reversible toxicity to the spinal cord.
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Objective To investigate the effects of ischemic pre- and postconditioning on cerebral glycogen synthase kinase-3 beta (GSK-3β) activity in a rat model of global cerebral ischemia-reperfusion (I/R).Methods Forty male Wistar rats weighing 200-230 g were randomly allocated into 4 groups (n =10 each) : Ⅰ group sham operation (group S); Ⅱ group I/R; Ⅲ group ischemic preconditioning (group IPR) and Ⅳ group ischemic postconditioning (group IPO). The animals were anesthetized with intraperitoneal 10% chloral hydrate 0.4 ml/100 g. Global cerebral ischemia was induced by four-vessel-occlusion in group Ⅱ , Ⅲ and Ⅳ. Bilateral vertebral arteries were cauterized and bilateral carotid arteries were occluded for 10 min. In group IPR cerebral ischemia was preceded by 3 cycles of 10 s ischemia followed by 30 s reperfusion. The group IPO received 3 cycles of 30 s reperfusion followed by 10 s ischemia at the end of 10 min cerebral ischemia. The animals were killed 2 days later. The brains were immediately removed for determination of neuronal apoptosis in the cortex (by TUNEL), the infarct size (by TTC), p-GSK-3β activity (by spectrum assay) and the expression of Bcl-2, Bax and Caspase-3 (by SP). Linear correlation of p-GSK-3β activity with the number of apoptotic neurons in the cortex and cerebral infarct size was analyzed. Results Cerebral I/R significantly increased the number of apoptotic neurons in the cortex and infarct size, decreased p-GSK-3β activity, down-regulated Bcl-2 expression and up-regulated Bax and Caspase-3 expression in group I/R as compared with group S. Ischemic pre- and postconditioning significantly attenuated these cerebral I/R-induced changes. The p-GSK-3β activity was negatively correlated with the number of apoptotic neurons in the cortex and cerebral infarct size. Conclusion Ischemic pre- and postconditioning reduces cerebral I/R injury through inhibiting the activity of GSK-3β.