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Objective:To evaluate the effect of pre-injection of young rat plasma on cognitive dysfunction after cerebral ischemia-reperfusion (I/R) in aged rats and the role of phosphatidylinositol 3-kinase/serine threonine protein kinase (PI3K/Akt) signaling pathway.Methods:Seventy-two SPF-grade healthy male Sprague-Dawley rats, aged 18 months, weighing 600-650 g, were divided into 4 groups ( n=18 each) by the random number table method: control group (group C), cerebral I/R group (group IR), pre-injection of young rat plasma group (group P) and PI3K inhibitor LY294002 group (group LY). In group P and group LY, young rat plasma 100 μl/time was injected via the tail vein. In group C and group IR, the equal volume of normal saline was injected via the the tail vein, 2 times a week for 4 weeks. Then the model of cerebral I/R injury was developed under sevoflurane anesthesia in IR, P and LY groups. LY294002 0.3 mg/kg was injected through the tail vein at 1 h before anesthesia in LY group. The neurological deficit score (Longa score) was performed at 24 h after reperfusion, and then 6 rats were randomly sacrificed, and brain tissues were obtained to determine the cerebral infarct volume. Spontaneous mobility and anxiety-like behavior were assessed by the open field test at day 29 of reperfusion, and cognitive function was assessed by the novel object recognition test at day 30 of reperfusion. At the end of the behavioral test, rats were sacrificed, hippocampal tissues were isolated for determination of the expression of phosphorylated PI3K (p-PI3K), phosphorylated Akt (p-Akt), postsynaptic dense protein-95 (PSD-95) and synaptic vesicle protein (SYN) (by Western blot), and the dendritic length and dendritic spine density of neurons in the hippocampal CA1 region. Results:There was no significant difference in motor speed, distance traveled, and time of staying at the center of the open field among the four groups ( P>0.05). Compared with group C, the Longa score and cerebral infarct volume were significantly increased, the percentage of novel object exploration and discrimination index were decreased, the expression of p-PI3K, p-Akt, PSD-95 and SYN in hippocampal tissues was down-regulated, and the dendritic length and dendritic spine density of hippocampal neurons were decreased in IR, P and LY groups ( P<0.05). Compared with group IR, Longa score and cerebral infarct volume were significantly decreased, the percentage of novel object exploration and discrimination index were increased, the expression of p-PI3K, p-Akt, PSD-95 and SYN in hippocampal tissues was up-regulated, and the dendritic length and dendritic spine density of hippocampal neurons were increased in group P ( P<0.05), and no significant change was found in the parameters mentioned above in group LY ( P>0.05). Compared with group P, Longa score and cerebral infarct volume were significantly increased, the percentage of novel object exploration and discrimination index were decreased, the expression of p-PI3K, p-Akt, PSD-95 and SYN in hippocampal tissues was down-regulated, and the dendritic length and dendritic spine density of hippocampal neurons were decreased in group LY ( P<0.05). Conclusions:Pre-injection of young rat plasma can attenuate cognitive dysfunction after cerebral I/R in aged rats, and the mechanism is related to activation of hippocampal PI3K/Akt signaling pathway and improvement in synaptic plasticity.
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Objective:To evaluate the effect of esketamine on the efficacy of postoperative patient-controlled intravenous analgesia (PCIA) in the patients with moderate central sensitization undergoing high tibial osteotomy.Methods:Fifty-four patients of both sexes with moderate central sensitization, aged 45-64 yr, with body mass index of 18.0-32.5 kg/m 2, of American Society of Anesthesiologists Physical Status classification Ⅰ or Ⅱ, undergoing elective high tibial osteotomy, were divided into 2 groups ( n=27 each) using a random number table method: control group (group C) and esketamine group (group ES). Ultrasound-guided femoral nerve block was performed with 0.5% ropivacaine 30 ml on the operated side at 30 min before induction of anesthesia.In C and ES groups, midazolam 0.1 mg/kg, sufentanil 0.2 μg/kg, propofol 1.5 mg/kg, and cisatracurium besilate 0.15 mg/kg were intravenously injected in turn during induction of anesthesia, and in addition esketamine hydrochloride 0.5 mg/kg was injected in ES group, and the equal volume of 0.9% sodium chloride was injected in C group, and then a laryngeal mask airway was placed.Anesthesia was maintained with intravenous infusion of remifentanil 0.1-0.3 μg·kg -1·min -1 and propofol 4-6 mg·kg -1·h -1.Esketamine hydrochloride 0.2 mg/kg was intravenously injected once every 20 min until 30 min before the end of operation in ES group, the equal volume of 0.9% sodium chloride was injected according to the amount of esketamine hydrochloride injected for the same body weight at the same time point in C group, and additional cisatracurium besilate was administered intermittently according to the degree of muscle relaxation.Intraoperative BIS values were maintained at 40-60.Postoperative PCIA was performed, and the patient was admitted to the post-anesthesia care unit.When the efficacy of PCIA was not good, ketorolac tromethamine 30 mg was intravenously injected for rescue analgesia.The intraoperative consumption of remifentanil and propofol and emergence time in the anesthesia recovery room were recorded.The pressing times of PCA and the number of rescue analgesia in each group were recorded within 2 days after operation.The Chinese Richards-Campbell Sleep Questionnaire was used to assess the nighttime sleep quality on the night of surgery and 1 and 2 days after surgery.The Chinese Quality of Recovery was used to assess the early recovery quality at 1 and 2 days after surgery.The first postoperative off-bed time and first walked distance were recorded.The adverse reactions were recorded. Results:Compared with group C, the consumption of remifentanil and propofol was significantly reduced, the emergence time in the anesthesia recovery room was prolonged, the pressing times of PCA and the number of rescue analgesia were decreased within 2 days after operation, the quality of nighttime sleep was improved on the night of surgery and 1 and 2 days after operation, the quality of early recovery on 1 and 2 days after operation was increased, the first postoperative off-bed time was shortened, the first walked distance was prolonged, and the incidence of postoperative adverse effects was decreased in group ES ( P<0.05). Conclusions:Esketamine can enhance the efficacy of postoperative PCIA in the patients with moderate central sensitization undergoing high tibial osteotomy.
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Objective:To evaluate the role of RhoA/ROCK2 signaling pathway in multiple exposures to sevoflurane-induced long-term cognitive impairment in neonatal rats.Methods:Sixty SPF healthy neonatal Sprague-Dawley rats of either sex, aged 6 days, weighing 12-20 g, were divided into 3 groups ( n=20 each) using a random number table method: control group (group C), multiple exposures to sevoflurane group (group S) and RhoA/ROCK2 signaling pathway inhibitor Y-27632 group (group Y). Group S and group Y inhaled 3% sevoflurane for 2 h at days 6, 7 and 8 after birth.In group Y, Y-27632 5 mg/kg was intraperitoneally injected before sevoflurane anesthesia.The spontaneous activity was evaluated by open field test on day 35 after birth.The cognitive function was detected by Morris water maze test at day 36 after birth.The rats were sacrificed after Morris water maze test, and the hippocampal tissues were isolated for determination of the apoptosis rate of hippocampal neurons and cytoplasmic calcium concentration ([Ca 2+ ] i) (by flow cytometry) and expression of phosphorylated RhoA (p-RhoA), ROCK2 and cleaved-caspase-3 (by Western blot) and for microscopic examination of the ultrastructure of hippocampal neurons (with a transmission electron microscope). Results:There was no significant difference in movement speed, distance and time of stay in the open field center in the open field test among the three groups ( P>0.05). Compared with group C, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the apoptosis rate of hippocampal neurons and [Ca 2+ ] i were increased, the expression of p-RhoA, ROCK2 and cleaved-caspase-3 was up-regulated ( P<0.05), and the pathological injury to hippocampal neurons was found in group S. Compared with group S, the escape latency was significantly shortened, the number of crossing the original platform was increased, the apoptosis rate of hippocampal neurons and [Ca 2+ ] i were decreased, the expression of p-RhoA, ROCK2 and cleaved-caspase-3 was down-regulated ( P<0.05), and the pathological injury to hippocampal neurons was attenuated in group Y. Conclusions:The mechanism by which multiple exposures to sevoflurane induces long-term cognitive impairment is related to activation of RhoA/Rock2 signaling pathway and induction of apoptosis rate of hippocampal neurons in neonatal rats.
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Objective:To evaluate the role of N-methyl-D-aspartate receptors (NMDA receptors) in sevoflurane anesthesia-caused necroptosis in hippocampal neurons of aged mice.Methods:Ninety clean-grade healthy male C57BL/6 mice, aged 18 months, weighing 27-30 g, were divided into 3 groups ( n=30 each) using a random number table method: control group (group C), sevoflurane anesthesia group (group S) and sevoflurane anesthesia plus NMDA receptor antagonist memantine hydrochloride group (group S+ M). Mice inhaled 3% sevoflurane for 2 h for 3 consecutive days in S group and S+ M group, and memantine hydrochloride 20 mg/kg was intraperitoneally injected at 1 h before each inhalation of sevoflurane in S+ M group.Mice only inhaled pure oxygen for 2 h in group C. Ten mice of each group were selected on 1 day before anesthesia and 3 and 7 days after anesthesia to perform Morris water maze test.The mice were sacrificed immediately after Morris water maze test, and hippocampus was removed for microscopic examination of pathological changes (with a light microscope) and for determination of the necroptosis rate of neurons and cytoplasmic free calcium concentration([Ca 2+ ] i)(by flow cytometry), and expression of NMDA receptor subtypes GluN2A, GluN2B and receptor-interacting protein kinase 1 (RIP1) (by Western blot). Results:Compared with group C, the escape latency was significantly prolonged, and the frequency of crossing the original platform was decreased, and the [Ca 2+ ] i and neuronal necroptosis rate in the hippocampus were increased at each time point after anesthesia, and the expression of GluN2A, GluN2B and RIP1 was up-regulated( P<0.05), and the pathologic changes were accentuated in S group and S+ M group.Compared with group S, the escape latency was significantly shortened, and the frequency of crossing the original platform was increased, and the [Ca 2+ ] i and neuronal necroptosis rate in the hippocampus were decreased at each time point after anesthesia, and the expression of GluN2A, GluN2B and RIP1 was down-regulated ( P<0.05), and the pathologic changes were attenuated in group S+ M. Conclusions:NMDA receptors are involved in the process of cognitive dysfunction induced by sevoflurane anesthesia in aged mice, and the mechanism may be related to the promotion of necrptosis in hippocampal neurons.
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Objective:To evaluate the role of brain-derived neurotrophic factor (BDNF)/tropomyosin-related kinase B (TrkB) signaling pathway in pre-injection of young rat plasma-induced reduction of sevoflurane-caused cognitive dysfunction in aged rats.Methods:Eighty SPF healthy male Sprague-Dawley rats, aged 18 months, weighing 550-650 g, were divided into 4 groups ( n=20 each) using a random number table method: control group (group C), sevoflurane anesthesia group (group S), young rat plasma group (group Y) and BDNF/TrkB signaling pathway inhibitor K252a group (group K). The plasma 100 μl obtained from 3-month-old young rats was injected via the tail vein in group Y and group K, while the equal volume of normal saline was given via the tail vein in group C and group S, twice a week, for 4 weeks.In S, Y and K groups, 3% sevoflurane was inhaled for 3 h starting from the end of treatment, and BDNF/TrkB signaling pathway inhibitor K252a was injected via the tail vein before anesthesia in group K. The open field test and Morris water maze test were performed at 3 days after anesthesia to assess the spontaneous motor ability and cognitive function.Then the rats were sacrificed, and the hippocampal tissues were isolated for determination of the expression of BDNF, phosphorylated TrkB (p-TrkB), postsynaptic dense protein-95 (PSD-95) and synaptic vesicle protein (SYN) (by Western blot), dendritic length and dendritic ridge density of neurons in hippocampal CA1 area (by Golgi staining), and the number of synapses and length of synaptic active area (with a transmission electron microscope). Results:Compared with group C, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the expression of p-TrkB, BDNF, PSD-95 and SYN was down-regulated, and the dendritic length, dendritic ridge density, the number of synapses and length of synaptic active area were decreased in group S ( P<0.05). Compared with group S, the escape latency was significantly shortened, the number of crossing the original platform was increased, the expression of p-TrkB, BDNF, PSD-95 and SYN was up-regulated, and the dendritic length, dendritic ridge density, the number of synapses and length of synaptic active area were increased in group Y ( P<0.05). Compared with group Y, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the expression of p-TrkB, BDNF, PSD-95 and SYN was down-regulated, and the dendritic length, dendritic ridge density, the number of synapses and length of synaptic active area were decreased in group K ( P<0.05). Conclusions:The mechanism by which pre-injection of young rat plasma reduces sevoflurane-induced cognitive dysfunction is related to activation of BDNF/TrkB signaling pathway and improvement in synaptic plasticity in the hippocampus of aged rats.
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Objective:To evaluate the effect of sevoflurane on necroptosis in isolated hippocampal neurons and the relationship with ryanodine receptor.Methods:Primarily cultured hippocampal neurons of fetal rats of Sprague-Dawley rats were inoculated in culture wells (100 μl/well) or culture flasks (3 ml/bottle) at a density of 5×10 5 cells/ml at 7 days of culture and divided into 3 groups ( n=24 each) using a random number table method: control group (group C), sevoflurane group (group S) and ryanodine receptor antagonist group (group R). Group C received routine culture.Ryanodine receptor antagonist Dantrolene at a final concentration of 3 μmol/L was added in group R. Thirty minutes later, the cells were placed in the incubator containing 2% sevoflurane and cultured for 5 h at 37 ℃ in S and R groups.Then cells were collected, the morphology of neurons was observed with an inverted microscope, the concentrations of free calcium ion ([Ca 2+ ] i) in cytoplasm were determined by flow cytometry, the expression of ryanodine receptor and phosphorylated MLKL protein (p-MLKL) was detected by Western blot, the expression of RIP3 was measured by immunofluorescence, and necroptosis rate was calculated. Results:Compared with group C, the [Ca 2+ ] i were significantly increased, the expression of ryanodine receptor and p-MLKL was up-regulated, and the necroptosis rate was increased in S and R groups ( P<0.05). Compared with group S, the expression of ryanodine receptor and p-MLKL was significantly down-regulated, and the [Ca 2+ ] i and necroptosis rate were decreased in group R ( P<0.05). There was no obvious abnormality in the morphology of neurons in group C. The cell body of neurons were shrunk, the processes were broken, and the network between processes was sparse in group S. The cell body was round, and the morphology was close to normal in group R. Conclusion:Sevoflurane can cause necroptosis in isolated hippocampal neurons of rats, and the mechanism is related to up-regulating the expression of ryanodine receptors and leading to calcium overload.
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Objective:To evaluate the role of reactive oxygen species (ROS)-mediated mitochondrial pathway of apoptosis in long-term cognitive impairment induced by multiple exposures to sevoflurane in the neonatal rats.Methods:Sixty SPF healthy neonatal Sprague-Dawley rats, weighing 12-20 g, were divided into 3 groups ( n=20 each) using a random number table method: control group (group C), multiple exposures to sevoflurane for anesthesia group (group S) and ROS inhibitor group (group A). Group S and group A inhaled 3% sevoflurane for 2 h starting from 6, 7 and 8 days after birth, while group C inhaled air.In group A, ROS inhibitor N-acetylcysteine (NAC) 150 mg/kg was intraperitoneally injected before each anesthesia with sevoflurane.The spontaneous activity was evaluated by open field test on day 35 after birth.The cognitive function was determined by Morris water maze test on day 36 after birth.The rats were sacrificed after the end of Morris water maze test, and the hippocampal tissues were obtained for determination of the apoptosis rate of hippocampal neurons, reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) (by flow cytometry) and levels of Cyt c and cleaved caspase-9 and caspase-3 (by Western blot). The expression of Bcl-2 and Bax mRNA was detected by real-time polymerase chain reaction.The ultrastructure of mitochondria in hippocampal neurons was observed with a transmission electron microscope. Results:Compared with group C, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the apoptosis rate of hippocampal neurons and levels of ROS and MMP were increased, the expression of Cyt c, cleaved caspase-9, cleaved caspase-3 and Bax mRNA was up-regulated, the expression of Bcl-2 mRNA was down-regulated, the ratio of Bax/Bcl-2 was increased ( P<0.05), mitochondria were swollen, and mitochondrial cristae structure was broken in group S. Compared with group S, the escape latency was significantly shortened, the number of crossing the original platform was increased, the apoptosis rate of hippocampal neurons and levels of ROS and MMP were decreased, the expression of Cyt c, cleaved caspase-9, cleaved caspase-3 and Bax mRNA was down-regulated, the expression of Bcl-2 mRNA was up-regulated, the ratio of Bax/Bcl-2 was decreased ( P<0.05), and the mitochondrial swelling and rupture of cristae structure were improved in group A. Conclusion:The mechanism by which multiple exposures to sevoflurane induce long-term cognitive impairment may be related to activating the ROS-mediated mitochondrial pathway of apoptosis in neonatal rats.
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Objective:To evaluate the effect of pre-infusion of young rat plasma on cognitive dysfunction induced by sevoflurane in aged rats and the role of extracellular regulated protein kinase (ERK)-cyclic adenosine monophosphate effector binding protein (CREB) signaling pathway.Methods:One hundred and twenty SPF healthy male Wistar rats, aged 18 months, weighing 550-650 g, were divided into 4 groups ( n=30 each) using a random number table method: control group (group C), sevoflurane anesthesia group (group S), young rat plasma group (group P) and ERK inhibitor SL327 group (group SL). The teated plasma 100 μl from 3-month-old young rats was injected via the tail vein in group P and group SL, while the equal volume of normal saline was given via the tail vein in group C and group S, twice a week, for 4 weeks.In S, P and SL groups, 3% sevoflurane was inhaled for 3 h at the end of injection, and ERK inhibitor SL327 50 mg/kg was injected via the tail vein before anesthesia in group SL.The cognitive function was evaluated by Morris water maze test at 1 day before anesthesia and at 3 and 7 days after anesthesia.The rats were sacrificed, and their hippocampi were isolated for determination of the expression of phosphorylated ERK (p-ERK), p-CREB, synapsin, synapsin Ⅰ and synaptophysin and for examination of the ultrastructure of neurons (by transmission electron microscopy). The number of synapses was recorded. Results:Compared with group C, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the expression of p-ERK, p-CREB, synapsin, synapsin Ⅰ and synaptophysin was down-regulated, and the number of synapses was decreased at each time point after anesthesia in the other 3 groups ( P<0.05). Compared with group S, the escape latency was significantly shortened, the number of crossing the original platform was increased, the expression of p-ERK, p-CREB, synapsin, synapsin Ⅰ and synaptophysin was up-regulated, and the number of synapses was increased at each time point after anesthesia in P and SL groups ( P<0.05). Compared with group P, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the expression of p-ERK, p-CREB, synapsin, synapsin Ⅰ and synaptophysin was down-regulated, and the number of synapses was decreased in group SL ( P<0.05). Conclusion:Pre-infusion of young rat plasma can reduce cognitive dysfunction induced by sevoflurane in aged rats, and the mechanism is related to activation of ERK-CREB signaling pathway and improvement of synaptic plasticity.
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Objective:To evaluate the role of interleukin 1β (IL-1β)/c-Jun N-terminal kinase (JNK) pathway in sevoflurane-induced necroptosis of rat hippocampal neurons in vitro. Methods:Primarily cultured hippocampal neurons of Sprague-Dawley rat fetuses were inoculated into 96-well plates (cell density: 1×10 4 cells/ml, 200 μl/hole) and 6-well plates (cell density: 1×10 6 cells/ml, 2 ml/hole). The cells were divided into 3 groups ( n=20 each) using a random number table method after being cultured for 7 days: control group (group C), sevoflurane group (group S) and IL-1 receptor antagonist group (group I). Group C received routine culture, IL-1 receptor antagonist IL-1ra 1 μg/μl was added, and the cells were incubated for 30 min in group I, and in addition the cells were placed in the incubator containing 2% sevoflurane and cultured for 5 h at 37 ℃ in S and I groups.The cells were collected for microscopic examination of the morphology of neurons (with an inverted microscope) and for determination of the cell necroptosis rate (by flow cytometry), cell viability (by MTT method), and expression of IL-1β, interleukin-1 receptor type I (IL-1RI), interleukin-1 receptor accessory protein (IL-1RAcP), phosphorylated JNK (p-JNK) ), receptor-interacting protein 1 (RIP1), RIP3 and phosphorylated mixed lineage kinase-like (p-MLKL) (by Western blot ). Results:Compared with group C, the cell viability was significantly decreased, the necroptosis rate was increased, and the expression of IL-1β, IL-1RI, IL-1RAcP, p-JNK, RIP1, RIP3 and p-MLKL was up-regulated in group S ( P<0.05). Compared with group S, the cell viability was significantly increased, the necroptosis rate was decreased, and the expression of IL-1β, IL-1RI, IL-1RAcP, p-JNK, RIP1, RIP3 and p-MLKL was down-regulated in group I ( P<0.05). There was no obvious abnormality in the morphology of neurons in group C. The cell body of neurons was shrunk, the processes were broken, and the network between processes was sparse in group S. The cell body was round, and the morphology was close to normal in group I. Conclusion:The mechanism by which sevoflurane induces necroptosis of rat hippocampal neurons in vitro is related to activation of IL-1β/JNK pathway.
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Objective:To evaluate the effect of pre-infusion of young rat plasma on postoperative cognitive function in aged rats and role of phosphatidylinositol 3 kinase/serine-threonine protein kinase (PI3K/Akt) signaling pathway.Methods:Sixty SPF healthy male Sprague-Dawley rats, aged 18 months, weighing 550-650 g, were divided into 4 groups ( n=15 each) using a random number table method: control group (group C), operation group (group O), young rat plasma group (group P) and PI3K inhibitor LY294002 group (group LY). The young rat plasma 100 μl/time was injected via the caudal vein twice a week for 4 consecutive weeks in group P and group LY, while the equal volume of normal saline was given instead in group C and group O. Rats received internal fixation for unilateral tibial fracture under sevoflurane anesthesia in O, P and LY groups.Rats received no treatment in group C. PI3K inhibitor LY294002 0.3 mg/kg was injected through the caudal vein before anesthesia in group LY.The ability of spontaneous activity was evaluated by open field test at 3 days after surgery, and then the cognitive function was assessed by Morris water maze test.The rats were sacrificed after the end of behavioral testing, and the hippocampal tissues were isolated for determination of the expression of phosphorylated PI3K (p-PI3K), phosphorylated Akt (p-Akt), synapsin, synaptophysin I and synaptic vesicle protein (by Western blot) and for microscopic examination of the ultrastructure of hippocampal neurons (with a transmission electron microscope). The number of synapses was recorded. Results:There was no significant difference in the movement speed and length and time spent in the central zone among the four groups ( P>0.05). Compared with group C, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the expression of p-PI3K, p-Akt, synapsin, synaptophysin I and synaptic vesicle protein was down-regulated, and the number of synapses was reduced in O and LY groups ( P<0.05), and no significant change was found in the parameters mentioned above in group P ( P>0.05). Compared with group O, the escape latency was significantly shortened, the number of crossing the original platform was increased, the expression of p-PI3K, p-Akt, synapsin, synaptophysin I and synaptic vesicle protein was up-regulated, and the number of synapses was increased in group P ( P<0.05), and no significant change was found in the parameters mentioned above in group LY ( P>0.05). Compared with group P, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the expression of p-PI3K, p-Akt, synapsin, synaptophysin I and synaptic vesicle protein was down-regulated, and the number of synapses was reduced in group LY ( P<0.05). Conclusion:Pre-infusion of young rat plasma can improve postoperative cognitive function in aged rats, and the mechanism is related to activation of PI3K/Akt pathway and improvement of synaptic plasticity.
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Objective:To determine the median effective concentration (EC 50) of ropivacaine producing sensory-motor separation when used for femoral nerve block performed under ultrasound guidance. Methods:American Society of Anesthesiologists physical status Ⅰ-Ⅲ patients of both sexes, aged 18-64 yr, with body mass index of 18-30 kg/m 2, scheduled for elective arthroscopic knee surgery under general anesthesia, were enrolled in this study. Femoral nerve block was performed under ultrasound guidance.After successful location, ropivacaine 22 ml was injected with the initial concentration of 0.50%, and the ratio between the two consecutive concentrations was 1.1.The EC 50 of ropivacaine was determined by up-and-down sequential method.The positive response was considered as sensory block without motor block.The negative response was considered as sensory and motor block.When a negative response was found, the concentration was decreased in the next patient.When a positive response occurred, the concentration was increased in the next patient.Probit analysis was used to calculate the EC 50 and 95% confidence interval of ropivacaine producing sensory-motor separation when used for femoral nerve block which was performed under ultrasound guidance. Results:The EC 50 of ropivacaine producing sensory-motor separation was 0.186%, and the 95% confidence interval was 0.155%-0.205% when used for ultrasound-guided femoral nerve block. Conclusion:The EC 50 of ropivacaine producing sensory-motor separation is 0.186% when used for femoral nerve block performed under ultrasound guidance.
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Objective To evaluate the the relationship between the mechanism underlying electroacupuncture (EA)-induced improvement of postoperative cognitive dysfunction and mitochondrion-depend-ent apoptosis in hippocampal neurons of aged rats.Methods Seventy-two healthy male Sprague-Dawley rats,aged 18 months,weighing 500-550 g,were divided into 3 groups (n =24 each) using a random number table method:control group (group C),operation group (group O) and group EA.EA was performed at Baihui and Dazhui acupoints for 30 min using disperse-dense waves,with a frequency 2/15 Hz and intensity 1 mA,once a day for 5 consecutive days in group EA.Laparotomy was performed under 3％sevoflurane anesthesia after the end of EA stimulation in O and EA groups.Morris water maze test was performed on 1 day before operation and 3 and 7 days after operation to assess the cognitive function.Rats were sacrificed after the end of Morris water maze test,brains were removed,and hippocampal tissues were obtained for detection of apoptosis rate of hippocampal neurons and expression of hippocampal caspase-3 and cytochrome c (Cyt c) by Western blot.Results Compared with group C,the escape latency was significantly prolonged after operation,the frequency of crossing the original platform was reduced,the apoptotic rate of hippocampal neurons was increased,and the expression of caspase-3 and Cyt c was up-regulated in O and A groups (P＜0.05).Compared with group O,the escape latency was significantly shortened after operation,the frequency of crossing the original platform was increased,the apoptotic rate of hippocampal neurons was decreased,and the expression of caspase-3 and Cyt c was down-regulated in EA group (P＜0.05).Conclusion The mechanism by which EA improves postoperative cognitive dysfunction may be related to inhibiting mitochondrion-dependent apoptosis in hippocampal neurons of aged rats.
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Objective To evaluate the effect of sevoflurane anesthesia on cognitive impairment in rats with traumatic brain injury. Methods One hundred and and twenty healthy male Wistar rats, aged 2-3 months, weighing 190-220 g, were assigned into 4 groups ( n=30 each) using a random number table method: control group ( group C) , traumatic brain injury group ( group T) , sevoflurane anesthesia group ( group S) , and traumatic brain injury plus sevoflurane anesthesia group ( group T+S) . A 40 g hammer was freely dropped onto the left parietal bone window from a height of 20 cm to establish the traumatic brain inju-ry model in T and T+S groups. Twelve days later, S and T+S groups inhaled 3％ sevoflurane for 3 h, and C and T groups inhaled pure oxygen for 3 h. On 1 day before anesthesia and 3 and 7 days after anesthesia, 10 rats in each group were randomly selected for performing Morris water maze test. Rats were sacrificed af-ter the end of Morris water maze test, and the hippocampal tissues were obtained for determination of the apoptosis rate of hippocampal neurons, cytoplasmic calcium concentration [Ca2+]i (by flow cytometry), expression of glucose-regulated protein 78 ( GRP78) and CCAAT∕enhancer-binding protein homologous pro-tein ( CHOP ) ( by immunohistochemistry ) , and expression of caspase-3 and caspase-12 ( by Western blot) . Results Compared with group C, the escape latency was significantly prolonged, the number of crossing platform was decreased, the apoptosis rate of hippocampal neurons and [ Ca2+] i were increased, and the expression of caspase-3, caspase-12, GRP78 and CHOP in hippocampal tissues was up-regulated in S, T and T+S groups ( P<0. 05) . Compared with T and S groups, the escape latency was significantly prolonged, the number of crossing platform was decreased, the apoptosis rate of hippocampal neurons and [ Ca2+] i were increased, and the expression of caspase-3, caspase-12, GRP78 and CHOP in hippocampal tissues was up-regulated in group T+S ( P<0. 05 ) . Conclusion Sevoflurane anesthesia can accentuate cognitive impairment in rats with traumatic brain injury, and the mechanism may be related to aggravating the degree of endoplasmic reticulum stress-induced calcium overload and increasing the apoptosis rate of hip-pocampal neurons.
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Objective To evaluate the effect of nimodipine pretreatment on postoperative cognitive function in diabetic rats. Methods One hundred and eighty healthy male Wistar rats, aged 3-4 months, weighing 260-310 g, were divided into 6 groups ( n=30 each) using a random number table method: op-eration group ( O group) , diabetes mellitus group ( DM group) , diabetic cognitive impairment group ( DCI group) , nimodipine plus operation group ( N+O group) , nimodipine plus diabetes mellitus group ( N+DM group) and nimodipine plus diabetic cognitive impairment group ( N+DCI group) . Diabetes mellitus model was established by intraperitoneal injection of streptozotocin 55 mg∕kg. Nimodipine 1 mg∕kg was intraperito-neally injected at 6 weeks after establishing the model in DCI and N+DCI groups and at 2 weeks after estab-lishing the model in DM and N+DM groups, and laparotomy was performed under sevoflurane anesthesia at 30 min after the end of administration. Morris water maze test was performed at 1 day before operation and 3 and 7 days after operation. Then rats were sacrificed, and hippocampal tissues were taken for determination of the apoptotic rate of neurons, cytoplasmic calcium concentrations ( by flow cytometry) and expression of caspase-3 in hippocampus ( by Western blot) . Results Compared with the baseline at 1 day before opera-tion, the escape latency was significantly prolonged, the number of crossing the original platform was re-duced, the apoptotic rate of hippocampal neurons and cytosolic calcium concentrations were increased, and the expression of caspase-3 was up-regulated at each time point after operation in six groups ( P<0. 05 ) . Compared with group O, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the apoptotic rate of hippocampal neurons and cytosolic calcium concentrations were increased, and the expression of caspase-3 was up-regulated at each time point after operation in DM and DCI groups ( P<0. 05) . The escape latency was significantly shortened, the number of crossing the original platform was increased, the apoptotic rate of hippocampal neurons and cytosolic calcium concentrations were decreased, and the expression of caspase-3 was down-regulated at each time point after operation in group N+DM as compared with group DM and in group N+DCI as compared with group DCI ( P<0. 05) . Conclu-sion Nimodipine pretreatment can improve postoperative cognitive function in diabetic rats, and the mech-anism may be related to inhibiting calcium overload-induced apoptosis in neurons.
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Objective To evaluate the effect of nimodipine pretreatment on postoperative cognitive function in rats with chronic cerebral ischemia.Methods Sixty healthy male Sprague-Dawley rats,aged 3 months,weighing 250-350 g,were divided into 2 groups (n =30 each) using a random number table method:chronic cerebral ischemia operation group (group H) and nimodipine plus chronic cerebral ischemia operation group (group N+H).The chronic cerebral ischemia model was established by permanently ligating bilateral common carotid arteries of chloral hydrate-anesthetized rats.Rats underwent Morris water maze adaptive training for 5 days 2 weeks later.Nimodipine 1 mg/kg was intraperitoneally injected on 1st day after the end of adaptive training in group N+H,while the equal volume of normal saline was given instead in group H,and 30 min later splenectomy was performed under sevoflurane anesthesia in two groups.Ten rats in each group were selected on 1 day before operation and 3 and 7 days after operation and underwent Morris water maze test to assess cognitive function.The rats were then sacrificed,brains were removed,and hippocampal tissues were isolated for determination of apoptosis in hippocampal neurons and intracellular Ca2+concentrations([Ca2+]i) in cytoplasm and expression of Bcl-2 and Bax mRNA (by realtime polymerase chain reaction).The ratio of Bax mRNA to Bcl-2 mRNA was calculated.Results Compared with the baseline at 1 day before operation,the escape latency was significantly prolonged,the frequency of crossing the original platform was decreased,the apoptotic rate and [Ca2+] i were increased,Bcl2 mRNA expression was down-regulated,and Bax mRNA expression was up-regulated,and Bax mRNA/Bcl-2 mRNA ratio was increased at each time point after operation in two groups (P＜0.05).Compared with group H,the escape latency was significantly shortened,the frequency of crossing the original platform was increased,the apoptotic rate and [Ca2+]iwere decreased,Bcl-2 mRNA expression was up-regulated,and Bax mRNA expression was down-regulated,and Bax mRNA/Bcl-2 mRNA ratio was decreased at each time point after operation in group N+ H (P＜ 0.05).Conclusion Nimodipine pretreatment can improve the postoperative cognitive function of rats with chronic cerebral ischemia,and the mechanism may be related to inhibiting calcium overload-induced apoptosis in hippocampal neurons.
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Objective To evaluate the effect of laparotomy on cognitive function in rats with trau-matic brain injury and the relationship with calcium overload. Methods One hundred and fifty healthy male Wistar rats,aged 2~3 months,weighing 190~220 g,were assigned into 5 group ( n=30 each) using a ran-dom number table:blank group(group B),surgery group of blank rats(group BS),surgery group of sham rats (group SS),traumatic brain injury rats group( group T),surgery group of traumatic brain injury rats(group TS). TBI model was made in rats of group T and TS by Feeney method. Rats in group SS were only treated with cranial bone window without crainocerebral impact. Both group B and BS were normal rats. Then the rats in group BS,SS and TS group underwent laparotomy under sevoflurane anesthesia (the operation time was a-bout 3 hours) and the rats in group B and T inhaled pure oxygen for 3 hours after 20 days. One day before surgery,3 and 7 d after surgery,10 rats in each group were randomly selected for Morris water maze test. The hippocampus tissue of 10 rats were taken after the water maze test. The apoptosis rate and calcium concen-tration of hippocampal neurons were measured by flow cytometry,and the expression level of cleaved caspase-3 in hippocampal tissues was determined by Western blot. Results One day before surgery,compared with group B(the escape latency(9. 8±0. 8)s,the number of crossing platform (5. 8±0. 8),the apoptosis rate of hippocampal neurons ( 2. 5 ± 0. 9)%, calcium ion concentration ( 2. 3 ± 0. 2),the expression of cleaved caspase-3 (0. 22±0. 07) ),the escape latency of group T and group TS were prolonged (group T:(25. 5± 0. 7)s,P<0. 05;group TS:(25. 1±1. 1) s,P<0. 05),the number of crossing platform decreased (group T:(2. 7±0. 8),P<0. 05;group TS:(2. 8±0. 6),P<0. 05),the apoptosis rate of hippocampal neurons increased (group T:(5. 3±0. 6)%,P<0. 05;group TS:(5. 2±1. 0)%,P<0. 05),calcium ion concentration increased (group T:(3. 7±0. 4),P<0. 05;group TS:(3. 6±0. 5),P<0. 05) and the expression of cleaved caspase-3 increased (group T:(0. 45±0. 07),P<0. 05;group TS:(0. 44±0. 05),P<0. 05),the differences were statis-tically significant. Compared with the group SS,the escape latency ( 3 d after surgery:group SS:( 23. 8 ± 1. 3)s,group TS:(56. 4±2. 5)s,P<0. 05;7 d after surgery:group SS:(16. 6±1. 8)s,group TS:(38. 1±2. 1) s,P<0. 05)of the rats in group TS were prolonged,the number of crossing platform decreased (3 d after sur-gery:group SS:(2. 9±0. 6) ,group TS:(1. 1±1. 1) ,P<0. 05;7 d after surgery:group SS:( 4. 2± 1. 2) , group TS:(1. 7±1. 3),P<0. 05),the apoptosis rate of hippocampal neurons ( 3 d after surgery:group SS:(4. 8±0. 6)%,group TS:(14. 4± 0. 6)%,P<0. 05;7 d after surgery:group SS:(3. 8± 1. 1)%,group TS:(9. 6±1. 3)%,P<0. 05),calcium ion concentration ( 3 d after surgery:group SS:(3. 1± 0. 3),group TS:(6. 4±0. 5),P<0. 05;7 d after surgery:group SS:( 2. 6± 0. 3),group TS:( 4. 8± 0. 4),P<0. 05) ,the ex-pression of cleaved caspase-3 (3 d after surgery:group SS:( 0. 42± 0. 03),group TS:( 0. 88 ± 0. 08),P<0. 05;7 d after surgery:group SS:(0. 33±0. 05),group TS:(0. 63±0. 06),P<0. 05) in the hippocampus in-creased after surgery (P<0. 05). Compared with the T group,the escape latency (3 d after surgery:group T:( 18. 6±2. 0)s,group TS:(56. 4±2. 5)s,P<0. 05;7 d after surgery:group T:(13. 8±2. 6)s,group TS:(38. 1 ±2. 1)s,P<0. 05) of the rats in group TS were prolonged,the number of crossing platform (3 d after surger-y:group T:(3. 4±0. 5),group TS:(1. 1±1. 1),P<0. 05;7 d after surgery:group T:(4. 3±1. 2),group TS:(1. 7±1. 3),P<0. 05) decreased,the apoptosis rate of hippocampal neurons (3 d after surgery:group T:(4. 4±0. 7)%,group TS:( 14. 4 ± 0. 6)%,P<0. 05;7 d after surgery:( 3. 3 ± 1. 3)%,group TS:( 9. 6 ± 1. 3)%,P<0. 05),calcium ion concentration (3 d after surgery:group T:( 3. 4 ± 0. 4),group TS:( 6. 4 ± 0. 5),P<0. 05;7 d after surgery:group T:(3. 0±0. 3),group TS:(4. 8±0. 4),P<0. 05),the expression of cleaved caspase-3 (3 d after surgery:group T:(0. 40±0. 04),group TS:( 0. 88±0. 08),P<0. 05;7 d after surgery:(0. 35±0. 02),group TS:(0. 63±0. 06),P<0. 05) in the hippocampus increased after surgery(P<0. 05). Conclusion Laparotomy can aggravate the cognitive impairment of rats with traumatic brain injury and cause postoperative cognitive impairment,which may be related to the increased degree of calcium over-load and the increased rate of hippocampal neuron apoptosis.
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Objective To investigate the effects and mechanism of remifentanil on renal ischemia/reperfusion(IR) injury via mediating Fas apoptosis signal pathway in rats.Methods Sprague-Dawley rats were divided into 3 groups (n =20 each) by using the random number table method:sham operation group (S group),IR control group (IR group),experimental group (Rgroup).The renal IR model was prepared by clamping the bilateral renal arteries for 45 min followedby reperfusion in IR group and R group.In R group,remifentanil was infused at 1.0μg·kg-1 ·min-1 via the tail vein starting from 15 min before ischemia until 30 min of reperfusion.In S group and IR group,the same volume of physiological saline was given.At 15 min before ischemia and at 3 h,12 h,24 h of reperfusion,the renal tissue samples were obtained for detecting the apoptosis rate by flow cytometry,determining the level of Fas mRNA expression by RT-PCR,the level of caspase-8 and caspase-3 activation by Western blotting,and scoring the number of kidney tubules injury by Paller'method.Results In IR group,the renal tubular injury score,the apoptosis rate,the expression of Fas mRNA and the activation of caspase-3 in renal tissue increased at 3 h after reperfusion,and those continued to increase at 12 h after reperfusion and reached the peak at 24 h after reperfusion (P＜0.01),and the activity of caspase-8 increased at 3 b,reached the peak at 12 h after reperfusion and decreased at 24 h after reperfusion (P＜0.01).As compared with S group,the renal tubular injury score,apoptosis rate,the expression of Fas mRNA and the activation of caspase-3 at 3 h,12 h and 24 h of reperfusion and the activation of caspase-8 at 12 h,24 h of reperfusion were all increased in IR group and R group (P＜0.05 or 0.01).As compared with IR group,the renal tubular injury score,apoptosis rate,the expression of Fas mRNA and the activation of caspase-8 and caspase-3 at 3 h,12 h and 24 h of reperfusion were decreased in R group (P＜0.05 or 0.01).Conclusion Remifentanil inhibits cell apoptosis and alleviates renal IR damage by reducing the expression of Fas receptor and the activation of caspase-8 and caspase-3,and regulating the apoptotic signal pathway of Fas.
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Objective To evaluate the effect of nimodipine on postoperative delirium (POD) in elderly patients with lacunar infarction. Methods Sixty patients with lacunar infarction of both sexes, aged 65-80 yr, of American Society of Anesthesiologists physical status Ⅱor Ⅲ, scheduled for elective spinal surgery under general anesthesia, were divided into 2 groups (n= 30 each) using a random number table: control group (group C) and nimodipine group (group N). Nimodipine 7. 5 μg·kg-1 ·h-1 was in-travenously infused starting from 30 min before anesthesia induction until the end of surgery in group N, while the equal volume of normal saline was given in group C. At 30 min before infusing nimodipine (T1 ), immediately after tracheal intubation (T2 ), at 1 h after skin incision (T3 ) and at the end of surgery (T4 ), blood samples were taken from the radial artery and jugular bulb for blood gas analysis. Jugular bulb oxygen content, arterial-jugular bulb oxygen content difference, cerebral oxygen uptake rate and jugular-arterial lactate concentration difference were calculated. The concentrations of S100β protein and brain-derived neurotrophic factor (BDNF) in serum of the jugular bulb were measured by enzyme-linked immunosorbent as-say. The occurrence of POD was recorded within 3 days after operation. Results Compared with group C, jugular bulb oxygen content was significantly increased, and arterial-jugular bulb oxygen content difference and cerebral oxygen uptake rate were decreased at T3,4 , the concentrations of serum S100β protein were de-creased and the concentrations of brain-derived neurotrophic factor were increased at T2-4 , the incidence of POD was decreased (P<0. 05), and no significant change was found in jugular-arterial lactate concentra-tion difference at each time point in group N (P>0. 05). Conclusion Nimodipine can reduce the devel-opment of POD, and the mechanism may be related to improving intraoperative cerebral oxygen metabolism and reducing brain injury in elderly patients.
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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 nimodipine pretreatment on postoperative cognitive function in rats with cerebral ischemic stroke.Methods Sixty healthy male Sprague-Dawley rats,aged 3 months,weighing 250-350 g,were divided into 2 groups (n =30 each) using a random number table method:normal saline plus cerebral ischemic stroke group (group Ⅰ) and nimodipine plus cerebral ischemic stroke group (group N+Ⅰ).The cerebral ischemic stroke model was established by thread occlusion in two groups.Three weeks later,nimodipine 1 mg/kg was intraperitoneally injected in group N+Ⅰ,while the equal volume of normal saline was given instead in group Ⅰ,and 30 min later two groups underwent exploratory laparotomy under 1.7％ sevoflurane anesthesia.Eight rats in each group were randomly selected on 1 day before operation and 3 and 7 days after operation,and Morris water maze test was performed to assess cognitive function.The rats were then sacrificed,brains were removed,and hippocampal tissues were isolated for detection of apoptosis in hippocampal neurons,intracellular Ca2+concentration ([Ca2+]i) in cytoplasm and the expression of Bcl-2 and Bax mRNA (by real-time polymerase chain reaction).The ratio of Bax mRNA to Bcl-2 mRNA was calculated.Results Compared with the value at 1 day before operation,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,Bax mRNA expression was up-regulated,and Bax mRNA/Bcl-2 mRNA ratio was increased at each time point after operation in two groups (P＜0.05).Compared with group Ⅰ,the escape latency was significantly shortened,the frequency of crossing the original platform was increased,the apoptotic rate and [Ca2 +]i were decreased,Bcl-2 mRNA expression was up-regulated,Bax mRNA expression was down-regulated,and Bax mRNA/Bcl-2 mRNA ratio was decreased at each time point after operation in group N+Ⅰ (P＜0.05).Conclusion Nimodipine pretreatment can improve the postoperative cognitive function of rats with cerebral ischemic stroke,and the mechanism may be related to inhibiting calcium overload-induced apoptosis in hippocampal neurons.