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Objective:To investigate the arousal mechanism after sevoflurane anesthesia using orexinergic modulation in dorsal raphe nucleus(DRN) by optogenetic and chemogenetic techniques in rats.Methods:Forty-five healthy male Hcrt-Cre rats, aged 10-12 weeks, weighing 220-250 g, were divided into 6 groups by the random number table method: optical-excitatory group (CHR2 group, n=5), optical-inhibitory group (eNpHR group, n=5), optical-control group (O-CON group, n=5); chemogenetic-excitatory group (hm3Dq group, n=10), chemogenetic-inhibitory group (hm4Di group, n=10) and chemogenetic-control group (C-CON group, n=10). The optogenetic or chemogenetic techniques were used in each group. Three weeks after injecting the rat virus, anesthesia was induced and maintained with 2.7% sevoflurane anesthesia in 1.5 L/min O 2, and the EEG data were continuously recorded throughout the process. The burst suppression ratio (%BSR) was recorded at 2 min before and of laser stimulation. Combining optogenetic and chemogenetic strategies, it was investigated that whether activation of orexinergic projection to DRN could modulate anesthetic behaviors during sevoflurane anesthesia. Results:Compared with C-CON group, the recovery of righting reflex (RORR) time was significantly shortened after sevoflurane anesthesia in hm3Dq group ( P<0.05), and the RORR time was significantly prolonged after sevoflurane anesthesia in hm4Di group and eNpHR group ( P<0.05). Compared with O-CON group or the baseline at 2 min before light stimulation, the %BSR was significantly decreased during 473nm laser stimulation in CHR2 group ( P<0.05), and no statistically significant change was found in the %BSR during 473nm laser stimulation in eNpHR group ( P>0.05). Compared with O-CON group, the RORR time was significantly shortened after sevoflurane anesthesia in CHR2 group ( P<0.05). Conclusions:Lateral hypothalamic area orexin-DRN neural circuit plays a key role in promoting arousal from general anesthesia in rats.
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Objective:To evaluate the effects of different inhalation time on the minimum alveolar concentration (MAC) of sevoflurane in adult rats.Methods:Two hundred SPF healthy adult Sprague-Dawley rats (half male, half female), aged 8-10 weeks, weighing 200-260 g, were divided into 2 groups using a random number table method: inhalation of sevoflurane for 1 h group and inhalation of sevoflurane for 20 min group, with 100 rats in each group.Each group was subdivided into 10 subgroups with 10 rats in each subgroup, the initial concentration was preset at 1.50%, and the ratio between two successive concentrations r was 1.08.The tail clamping stimulus was applied to evaluate the efficacy of anesthesia in each subgroup, a positive response was defined as a body movement occurred within 1 min after tail clamping stimulus, and the response was defined as negative when no body movement occurred within 1 min after tail clamping.The Bliss method was used to calculate the MAC, EC 95 and 95% confidence interval (CI) of sevoflurane. Results:The MAC and EC 95 (95% CI) of sevoflurane were 2.09% (1.98%-2.20%) and 2.75% (2.56%-3.04%), respectively, in inhalation of sevoflurane for 1 h group, and 2.35% (2.22%-2.49%) and 3.10% (2.87%-3.45%), respectively, in inhalation of sevoflurane for 20 min group ( P<0.05). Conclusions:The MAC of sevoflurane in adult rats inhaled sevoflurane for 1 h is decreased than that inhaled for 20 min.
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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 investigate the mechanism of dexmedetomidine preventing sevoflurane-indued neurotoxicity to neonatal mice and the relationship with Tau phosphorylation.Methods:Seventy-two SPF healthy newly born C57BL/6 wild-type mice of both sexes, aged 6 days, were divided into 4 groups ( n=18 each) using a random number table method: normal control group (C group), dexmedetomidine control group (D group), sevoflurane-induced neurotoxicity group (S group), and dexmedetomidine prevention group (SD group). Mice inhaled 2.1%-3.3% sevoflurane 2 h daily on postnatal days 6, 9 and 12, and dexmedetomidine 10 μg/kg was intraperitoneally injected at 30 min before anesthesia in group SD.Six mice were randomly selected after the end of injection, and the hippocampus tissues were removed for determination of the expression of phosphorylated Tau protein (AT8) and Tau46 protein at Tau-PS202 and Tau-PT205 sites by Western blot.The new object recognition test was performed on postnatal days 29-30 (the discrimination ratio of new objects was observed), and the Morris water maze test was performed from postnatal day 31 to 37 (the escape latency and the times of crossing the platform were observed). The hippocampi were harvested under anesthesia to detect the expression of postsynapatic density-95 by Western blot. Results:Compared with group C, the expression of AT8 was significantly up-regulated, the expression of PSD-95 was down-regulated, the number of crossing the platform and new object discrimination ratio were decreased ( P<0.05), and no significant change was found in Tau46 protein expression or escape latency in group S ( P>0.05). There was no significant difference in the indexes mentioned above between group D and group SD ( P>0.05). Compared with group S, the expression of AT8 was significantly down-regulated, the expression of postsynapatic density-95 was up-regulated, the number of crossing the platform and new object discrimination ratio were increased ( P<0.05), and no significant change was found in Tau46 protein expression and escape latency in group SD ( P>0.05). Conclusions:The mechanism of dexmedetomidine preventing sevoflurane-induced neurotoxicity to neonatal mice is related to the inhibition of Tau phosphorylation.
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Objective:To evaluate the role of protein kinase A (PKA)-cyclic adenosine monophosphate response element binding protein (CREB) signaling pathway in sevoflurane-induced reduction of cardiopulmonary bypass (CPB)-induced cognitive impairment in rats.Methods:Forty healthy male Sprague-Dawley rats, aged 4 months, weighing 300-350 g, were divided into 4 groups ( n=10 each) using a random number table method: control group (group C), group CPB, CPB+ sevoflurane group (group CS) and CPB+ sevoflurane+ PKA inhibitor H89 group (group CSH). After H89 5 μl was injected into the lateral ventricle in group CSH, the rats in group CS and group CSH were exposed to 2.4% sevoflurane for 1 h, and then the CPB model of beating heart without blood priming for 60 min was developed in CPB, CS and CSH groups.The autonomic movement ability was evaluated using the open field test at 2nd day after CPB.Morris water maze test was used to assess the cognitive function at 3rd day after CPB.The rats were sacrificed after the Morris water maze test, the brain was removed and the hippocampal tissues were isolated for determination of the apoptosis rate of hippocampal neurons (by flow cytometry) and expression of PKA, phosphorylated CREB (p-CREB) and brain-derived neurotrophic factor (BDNF) (by Western blot). Results:There was no significant difference in movement speed, distance and time of staying at the central region 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 time of staying at the original platform quadrant was shortened, the apoptosis rate of hippocampal neurons was increased, and the expression of PKA, p-CREB and BDNF was down-regulated in the other three groups ( P<0.05). Compared with group CPB, the escape latency was significantly shortened, the number of crossing the original platform was increased, the time of staying at the original platform quadrant was prolonged, the apoptosis rate of hippocampal neurons was decreased, and the expression of PKA, p-CREB and BDNF was up-regulated in group CS ( P<0.05), and no significant change was found in the indexes mentioned above in group CSH ( P>0.05). Compared with group CS, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, and the time of staying at the original platform quadrant was shortened, the apoptosis rate of hippocampal neurons was increased, and the expression of PKA, p-CREB and BDNF was down-regulated in group CSH ( P<0.05). Conclusions:Sevoflurane can reduce the apoptosis in hippocampal neurons by activating PKA-CREB signaling pathway, and thus reducing the cognitive impairment induced by CPB in rats.
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Objective:To evaluate the role of glucagon-like peptide-1 receptor (GLP-1R) signaling pathway in sevoflurane postconditioning-induced attenuation of myocardial ischemia-reperfusion (I/R) injury in rats.Methods:Eighty SPF healthy adult male Sprague-Dawley rats, aged 8-10 weeks, weighing 300-340 g, were divided into 4 groups ( n=20 each) by a random number table method: sham operation group (group S), myocardial I/R group (group I/R), myocardial I/R plus sevoflurane postconditioning group (group ISP), and myocardial I/R plus sevoflurane postconditioning plus GLP-1R antagonist group (group ISPE). The myocardial I/R injury model was developed by ligating the left anterior descending branch of the coronary artery for 40 min followed by 2-h reperfusion in anesthetized rats.In group ISP, the rats inhaled 2.4% sevoflurane for 15 min starting from the beginning of reperfusion.In group ISPE, GLP-1R antagonist Exendin9-39 50 μg/kg (in 1 ml 0.9% normal saline) was intraperitoneally injected once a day from 28 days before development of the model, the last intraperitoneal injection was completed at 40 min before inhalation of sevoflurane, and the other treatments were the same as those previously described in group ISP.Blood samples from the abdominal aorta were collected immediately after reperfusion to determine the serum levels of creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH). Then the rats were sacrificed, and the hearts were obtained for microscopic examination of the histopathological changes of myocardial tissues (by HE staining) and the ultrastructure of cardiomyocytes (with a transmission electron microscope) for determination of the myocardial infarct size (TTC staining), expression of GLP-1R in myocardium (by immunohistochemical staining), expression of GLP-1R, cyclic adenosine monophosphate (cAMP), protein kinase A (PKA), cAMP response element-binding protein (CREB), phospho-CREB (p-CREB), B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated x protein (Bax) in myocardium (by Western blot). The ratios of p-CREB/CREB and Bcl-2/Bax were calculated. Results:Compared with group S, the serum levels of CK-MB and LDH and percentage of myocardial infarct size were significantly increased, the expression of GLP-1R was up-regulated, the expression of cAMP and PKA was down-regulated, and the p-CREB/CREB ratio and Bcl-2/Bax ratio were decreased in group I/R ( P<0.05). Compared with group I/R, the serum levels of CK-MB and LDH and percentage of myocardial infarct size were significantly decreased, the expression of GLP-1R, cAMP and PKA was up-regulated, and p-CREB/CREB ratio and Bcl-2/Bax ratio were increased in group ISP ( P<0.05). Compared with group ISP, the serum levels of CK-MB and LDH and percentage of myocardial infarct size were significantly increased, the expression of GLP-1R, cAMP and PKA was down-regulated, and the p-CREB/CREB ratio and Bcl-2/Bax ratio were decreased in group ISPE ( P<0.05). Conclusions:Sevoflurane postconditioning can attenuate myocardial I/R injury by activation of GLP-1R signal pathway and inhibition of cardiomyocyte apoptosis in 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 1, 4, 5-inositol triphosphate receptor (IP3R) in necroptosis of hippocampal neurons induced by sevoflurane anesthesia in aged rats.Methods:Sixty healthy male Sprague-Dawley rats, aged 18 months, weighing 500-600 g, were divided into 3 groups ( n=20 each) using a random number table method: control group (group C), sevoflurane anesthesia group (group S) and sevoflurane anesthesia + IP3R antagonist group (group S+ I). S and S+ I groups inhaled 2% sevoflurane for 5 h. In group S+ I, IP3 receptor antagonist 2-APB 3 mg/kg was intraperitoneally injected at 10 min before sevoflurane inhalation, and the equal volume of dimethyl sulfoxide was intraperitoneally injected in group C and group S. Morris water maze test was used to test the cognitive function on the day after the end of sevoflurane anesthesia.Then the animals were sacrificed and the brain tissues were obtained for microscopic examination of the pathological changes after HE staining and Nissl staining (with a light microscope) and for determination of the free calcium concentration ([Ca 2+ ] i) and rate of necroptosis of hippocampal neurons (by flow cytometry) and expression of IP3R, receptor-interacting protein kinase-1 (RIPK1), receptor-interacting protein kinase-3 (RIPK3) and phosphorylated mixed lineage kinase domain-like protein (p-MLKL) (by Western blot). Results:Compared with group C, the escape latency was significantly prolonged, the times of crossing the platform were reduced, the time of staying at the target quadrant was shortened, the [Ca 2+ ] i and necroptosis rate of hippocampal neurons were increased, and the expression of IP3R, RIPK1, RIPK3 and p-MLKL in hippocampal neurons was up-regulated in group S and group S+ I ( P<0.05). Compared with group S, the escape latency was significantly shortened, the times of crossing the platform were increased, the time of staying at the target quadrant was prolonged, the [Ca 2+ ] i and necroptosis rate of hippocampal neurons were decreased, and the expression of IP3R, RIPK1, RIPK3 and p-MLKL in hippocampal neurons was down-regulated in group S+ I ( P<0.05). Conclusions:The mechanism by which sevoflurane induces cognitive dysfunction may be related to the imbalance of calcium homeostasis caused by activation of IP3R and thus inducing programmed necrosis in aged rats.
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Objective:To evaluate the effects of exosomes derived from cardiac fibroblasts pretreated with sevoflurane on ventricular electrical conduction in isolated rat hearts subjected to hypothermic ischemia-reperfusion (I/R) using the multi-electrode array mapping technique.Methods:Primary cardiac fibroblasts were extracted by differential adhesion in SPF Sprague-Dawley rats of either sex.Cardiac fibroblasts of passage 2-4 were treated with 2.5% sevoflurane for 1 h, and then cultured for 24-48 h to extract exosome.SPF healthy male Sprague-Dawley rats, aged 2-3 months, weighing 280-320 g, were divided into 3 groups ( n=8 each) using a random number table method: control group (group C), I/R group and sevoflurane-pretreated cardiac fibroblast-derived exosome+ IR group (group S+ IR). Hearts were perfused for 110-min equilibration in group C. After 20 min of equilibration, the perfusion was suspended for 60 min (global ischemia) followed by 30 min of reperfusion in IR and S+ IR groups.Exosomes 1 ml (200 μg) derived from cardiac fibroblasts pretreated with sevoflurane were injected through the tail vein at 48 h before surgery in group S+ IR, and the equal volume of normal saline was injected instead in C and IR groups.The cardiac conduction velocity (CV), conduction absolute inhomogeneity (P 5-95) and inhomogeneity index (P 5-95/P 50) were obtained at 20 min of equilibration (T 0) and 15 and 30 min of reperfusion (T 1, 2) using the microelectrode array attaching to the left ventricular surface of the isolated heart. Results:Compared with group C, CV was significantly decreased and P 5-95 and P 5-95/P 50 were increased at T 1 ( P<0.05), and no significant change was found at T 2 in group S+ IR ( P>0.05), and CV was significantly decreased and P 5-95 and P 5-95/P 50 were increased at T 1, 2 in group IR ( P<0.05). Compared with group IR, CV was significantly increased and P 5-95 and P 5-95/P 50 were decreased at T 1, 2 in group S+ IR ( P<0.05). Conclusions:Exosomes derived from cardiac fibroblasts pretreated with sevoflurane can improve ventricular electrical conduction in isolated rat hearts subjected to hypothermic I/R.
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Objective:To evaluate the effect of dexmedetomidine pretreatment on the autophagy of hippocampal neurons in the developing rats under sevoflurane anesthesia.Methods:Thirty-six clean-grade healthy Sprague-Dawley rats of either sex, aged 7 days, weighing 12-15 g, were divided into 3 groups ( n=12 each) using a random number table method: control group (group C), sevoflurane group (group S), and sevoflurane plus dexmedetomidine group (group S+ D). On 7-9 days after birth, and the animals were exposed to 3% sevoflurane (oxygen concentration inhaled 29%, oxygen flow 2 L/min, 2 h/day) after intraperitoneal injection of 25 μg/kg dexmedetomidine every day in group S+ D, the animals were exposed to sevoflurane after intraperitoneal injection of the equal volume of normal saline in group S, and the animals were exposed to gas mixture after intraperitoneal injection of the equal volume of normal saline in group C. The Morris water maze test was carried out at 20 days after birth, and the place navigation test and spatial probe test were performed.After the end of Morris water maze test, the anesthetized rats were sacrificed, and the hippocampus was obtained for determination of the expression of microtubule-associated protein light chain 3(LC3), BECN1 and P62 by Western blot. Results:Compared with group C, the escape latency was significantly prolonged, the frequency of crossing the original platform was decreased, the expression of LC3 and BECN1 was up-regulated, and the expression of P62 was down-regulated in group S and group S+ D ( P<0.05). Compared with group S, the escape latency was significantly shortened, the frequency of crossing the original platform was increased, the expression of LC3 and BECN1 was down-regulated, and the expression of P62 was up-regulated in group S+ D ( P<0.05). Conclusions:The mechanism by which dexmedetomidine pretreatment improves sevoflurane-induced cognitive dysfunction is related to reduction of excessive autophagy in hippocampal neurons of developing rats.
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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 relationship between long-term learning and memory impairment induced by sevoflurane anesthesia and postsynaptic density protein-95 (PSD-95)/Kalirin-7/Ras-related C3 botulinum toxin substrate 1 (Rac1) signaling pathway in neonatal rats.Methods:Sixty SPF male Wistar rats, aged 7 days, weighing 12-18 g, were divided into 5 groups ( n=12 each) using a random number table method: control group (group C), 1% sevoflurane anesthesia for 2 h group (group S 1), 1% sevoflurane anesthesia for 4 h group (group S 2), 2% sevoflurane anesthesia for 2 h group (group S 3) and 2% sevoflurane anesthesia for 4 h group (group S 4). Morris water maze test was performed at 4, 8 and 12 weeks after anesthesia.The rats were sacrificed after the last Morris water maze test, and the hippocampal tissues were obtained for microscopic examination of the pathological changes (using HE staining), neuron apoptosis (by TUNEL staining), and expression of PSD-95, Kalirin-7 and Rac1 protein and mRNA (by Western blot and quantitative real-time polymerase chain reaction). The apoptosis rate was calculated. Results:Compared with group C, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the time of stay in the target quadrant was shortened, and the apoptosis rate of hippocampal neurons was increased at 4th, 8th and 12th weeks after anesthesia, phosphorylated Rac1/Rac1 ratio was decreased, and the expression of PSD-95 and Kalirin-7 protein and mRNA was down-regulated in S 1, S 2, S 3 and S 4 groups ( P<0.05). Compared with group S 4, the escape latency was significantly shortened, the number of crossing the original platform was increased, the time of stay in the target quadrant was prolonged, and the apoptosis rate of hippocampal neurons was decreased, phosphorylated Rac1/Rac1 ratio was increased, the expression of PSD-95 and Kalirin-7 protein and mRNA was up-regulated, and the histopathological changes of hippocampal tissues were attenuated in S 1, S 2 and S 3 groups ( P<0.05). Conclusions:The mechanism by which sevoflurane anesthesia induces long-term learning and memory impairment may be related to inhibition of activity of PSD-95/Kalirin-7/Rac1 signaling pathway in hippocampi of neonatal rats.
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Objective:To investigate the effect of diabetes mellitus on pulmonary uptake of sevoflurane.Methods:Twenty patients with type 2 diabetes mellitus, aged 40-64 yr, with body mass index of 18.5-22.9 kg/m 2, of American Society of Anesthesiologists physical status Ⅰ or Ⅱ, undergoing elective surgery with general anesthesia, served as diabetes group (group D). Twenty non-diabetic patients matched by age, gender and surgery were selected as control group (group C). After anesthesia induction and tracheal intubation, sevoflurane was inhaled at a concentration of 2% (oxygen flow 2 L/min). The inhaled concentration (Fi) and exhaled concentration (Fa) at 1, 3, 5, 10, 15, 20 and 30 min of inhalation of sevoflurane were recorded, and the Fa/Fi ratio was calculated.The time required for the Fa/Fi ratio to reach 0.7 was recorded. Results:Compared with group C, the Fa/Fi ratio was significantly increased at each time point, and the time required for the Fa/Fi ratio to reach 0.7 was shortened in group D ( P<0.05). Conclusion:Diabetes mellitus can reduce pulmonary uptake of sevoflurane in the patients.
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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 investigate the role of receptor-interacting protein kinse3 (RIPK3)-mediated necroptosis in diabetic mellitus-caused abolition of cardioprotection induced by sevoflurane postconditioning in rats.Methods:Eighty rats with diabetes mellitus, aged 4-5 weeks, weighing 90-100 g, were divided into 4 groups ( n=20 each) using a random number table method: sham operation group (group Sham), myocardial ischemia-reperfusion (I/R) group (group I/R), sevoflurane postconditioning group (group SP) and sevoflurane postconditiong plus RIPK3 inhibitor GSK-872 group (group GSK). Myocardial I/R was induced by 40 min occlusion of the left anterior descending branch of the coronary artery followed by 120 min reperfusion.In group SP, 2.4% sevoflurane was inhaled for 15 min at the beginning of reperfusion.In group GSK, GSK-872 3.3 mg/kg (dissolved in normal saline) was intraperitoneally injected at 24 and 2 h before surgery, and the other treatments were similar to those previously described in group SP.After 120 min of reperfusion, blood samples from the abdominal aorta were collected for determination of concentrations of serum lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB). Myocardial tissues were taken for determination of percentage of myocardial infarct size (by TTC staining) and expression of RIPK3, phospho-Ca 2+ -calmodulin-dependent protein kinase Ⅱ (p-CaMKⅡ) and phospho-mixed lineage kinase domain-like protein (p-MLKL) (by Western blot), and the ultrastructure of myocardium was observed by transmission electron microscopy. Results:Compared with group Sham, the serum LDH and CK-MB concentrations and percentage of myocardial infarct size were significantly increased, the expression of RIPK3, p-MLKL and p-CaMKⅡ in myocardial tissues was up-regulated ( P<0.05), and the damage to cardiomyocytes was severe in group I/R.Compared with group I/R, no significant change was found in the parameters mentioned above in group SP ( P>0.05). Compared with group SP, the serum LDH and CK-MB concentrations and percentage of myocardial infarct size were significantly decreased, the expression of RIPK3, p-MLKL and p-CaMKⅡ in myocardial tissues was down-regulated ( P<0.05), and the damage to cardiomyocytes was reduced in group GSK. Conclusion:The mechanism of diabetic mellitus-caused abolition of cardioprotection induced by sevoflurane postconditioning is related to excessive activation of RIPK3-mediated necroptosis in rats.
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Objective:To evaluate the role of hippocampal β-amyloid 42 (Aβ 42) deposition-induced accumulation of neutrophils in blood-brain barrier damage caused by sevoflurane anesthesia in aged rats. Methods:Seventy-two healthy male Wistar rats in which IT catheters were successfully planted, aged 18-20 months, weighing 600-650 g, were divided into 4 groups ( n=18 each) using a random number table method: control group (group C), γ-secretase inhibitor DAPT group (group D), sevoflurane anesthesia group (group S) and DAPT plus sevoflurane anesthesia group (group DS). Dimethyl sulfoxide 10 μl was intrathecally injected in group C and group S, and 30 min later group C inhaled 60% oxygen for 2 h, and group S inhaled 3.6% sevoflurane and 60% oxygen for 2 h and tibial fracture surgery was performed at the same time.DAPT 10 μl was intrathecally injected in group D and group DS, and 30 min later group D inhaled 60% oxygen for 2 h, and group DS inhaled 3.6% sevoflurane and 60% oxygen for 2 h and tibial fracture surgery was performed at the same time.The fear conditioning test was performed at 12 h after the end of treatment in each group, and the ratio of time spent freezing was calculated.The rats were sacrificed after the end of behavioral test, and hippocampal tissues were removed for determination of the expression of Aβ 42, occludin and matrix metalloproteinase-9 (MMP-9) (by Western blot), neutrophil count (by immuno-histochemistry), and content of Evans blue (EB) (by EB staining). Results:Compared with group C, the ratio of time spent freezing was significantly decreased, the expression of Aβ 42 and MMP-9 was up-regulated, the expression of occludin was down-regulated, the neutrophil count and content of EB were increased in group S and group DS ( P<0.05), and no significant change was found in the parameters mentioned above in group D ( P>0.05). Compared with group S, the ratio of time spent freezing was significantly increased, the expression of Aβ 42 and MMP-9 was down-regulated, the expression of occludin was up-regulated, the neutrophil count and content of EB were decreased in group DS ( P<0.05). Conclusion:The mechanism by which sevoflurane anesthesia leads to postoperative cognitive dysfunction is related to hippocampal Aβ 42 deposition-induced accumulation of neutrophils and causing damage to blood-brain barrier in aged rats.
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Objective:To evaluate the relationship between phosphorylation of Tau protein and apolipoprotein E (ApoE) containing 18 kDa fragments and investigate the mechanism of neuronal damage induced by sevoflurane.Methods:Primary neurons (ApoE3 and ApoE2 genotypes, 24 dishes for each genotype) of fetal mice cultured until the 5th day were divided into 4 groups ( n=12 each) using a random number table method: ApoE3 control group (A3C group), ApoE3 sevoflurane group (A3S group), ApoE2 control group (A2C group) and ApoE2 sevoflurane group (A2S group). Neurons were treated with 21% oxygen + 5% carbon dioxide + 4.1% sevoflurane for 4 h in A3S and A2S groups, while the neurons were only treated with 21% oxygen + 5% carbon dioxide in A3C and A2C groups.The cell proteins were then extracted to detect the expression of full-length ApoE and ApoE, AT8 and PHF1 containing 18 kDa fragments (by Western blot), expression of ApoE mRNA (by real-time polymerase chain reaction), and concentrations of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in the supernatant (by enzyme-linked immunosorbent assay). Results:Compared with A2C group, the expression of ApoE mRNA and full-length ApoE in neurons was up-regulated ( P<0.05), and no significant change was found in the expression of AT8 and PHF1 and concentrations of TNF-α and IL-6 in the supernatant in A2S group ( P>0.05). Compared with A3C group, the expression of ApoE mRNA, full-length ApoE, and ApoE, AT8 and PHF1 containing 18 kDa fragments was up-regulated, and the concentrations of TNF-α and IL-6 in the supernatant were increased in A3S group ( P<0.05). Conclusion:Sevoflurane may promote phosphorylation of Tau proteins and increase inflammatory responses through up-regulating the expression of ApoE containing 18 kDa fragments, thus leading to neuronal damage.
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Objective:To evaluate the relationship between phosphorylation of glycogen synthase kinase-3β (GSK-3β) and high glucose-caused abolition of cardioprotection induced by sevoflurane postconditioning.Methods:H9c2 cells were incubated in normal glucose (5.56 mmol/L) DMEM culture medium or high glucose (33 mmol/L) DMEM culture medium.The cells were divided into 8 groups ( n=24 each) using a random number table method: normal control group (group NC), normal glucose-cultured hypoxia/reoxygenation (H/R) group (group NH/R), normal glucose-cultured sevoflurane postconditioning group (group NS), normal glucose-cultured GSK-3β inhibitor SB216763 group (group NSB), high glucose-cultured group (group HC), high glucose-cultured H/R group (group HH/R), high glucose-cultured sevoflurane postconditioning group (group HS) and high glucose-cultured GSK-3β inhibitor SB216763 group (group HSB). The model of cardiomyocyte H/R was established by subjecting cardiomyocytes to 3 h of hypoxia followed by reoxygenation.Immediately after onset of reoxygenation, cardiomyocytes were exposed to 2.4% sevoflurane for 30 min in Ns and HS groups.Before the beginning of reoxygenation, GSK-3β inhibitor SB216763 was added to the culture medium with the final concentration of 10 μmol/L in NSB and HSB groups.At 3 h of reoxygenation, the apoptosis rate was determined by Anexin V-PI flow cytometry, the expression of GSK-3β and phosphorylated GSK-3β (p-GSK-3β) was detected by Western blot, superoxide dismutase (SOD) activity was measured using xanthineoxidase method, and lactic dehydrogenase (LDH) activity and malondialdehyde (MDA) content were determined by colorimetric assay. Results:Compared with group NC, apoptosis rate, LDH activity and MDA content were significantly increased, and SOD activity was decreased in group NH/R and group HC, expression of GSK-3β was up-regulated, and expression of p-GSK-3β was down-regulated in group NH/R, expression of p-GSK-3β was up-regulated in group NS, and expression of p-GSK-3β was down-regulated in group HC ( P<0.05). Compared with group NH/R, apoptosis rate, LDH activity and MDA content were significantly decreased, and SOD activity was increased in group NS and NSB groups, and expression of GSK-3β was down-regulated, and expression of p-GSK-3β was up-regulated in group NS ( P<0.05). Compared with group HC, apoptosis rate, LDH activity and MDA content were significantly increased, SOD activity was decreased, expression of GSK-3β was up-regulated, and expression of p-GSK-3β was down-regulated in group HH/R ( P<0.05). Compared with group HH/R, apoptosis rate, LDH activity and MDA content were significantly decreased, and SOD activity was increased in group HSB ( P<0.05). Conclusion:The mechanism by which high glucose abolishes cardioprotection induced by sevoflurane postconditioning is related to inhibiting phosphorylation of GSK-3β.
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Objective:To systematically review the effect of prophylactic use of propofol on emergence agitation (EA) following sevoflurane anesthesia in pediatric patients.Methods:Databases such as Pubmed, Web of Scince, Embase, Cochrane Library, ClinicalTrials.gov, CNKI, Wanfang Data and VIP were searched for randomized controlled trials involving the comparison of effects of propofol (1 mg/kg) versus normal saline on EA following sevoflurane anesthesia in pediatric patients using computers from inception to December 1, 2020.Evaluation indexes included incidence of agitation, Pediatric Anesthesia Emergence Delirium (PAED) scale, awakening time, postanesthesia care unit (PACU) stay time and incidence of adverse events.The Cochrane Collaboration′s tool for assessing risk of bias was used to evaluate the quality of the included trials.The meta-analysis was conducted using the RevMan 5.3 and Stata 12.0 softwares.Results:Sixteen randomized controlled clinical trials involving 1 061 patients were included in this meta-analysis.The patients were divided into 2 groups: propofol group ( n=531) and normal saline group ( n=530). Compared with group normal saline, incidence of EA and PAED score were significantly decreased in group propofol ( P<0.05), and there was no significant difference in the incidence of postoperative nausea and vomiting, incidence of other adverse events and PACU stay time between the 2 groups ( P>0.05). Conclusion:Prophylactic dose of propofol (1 mg/kg) for sevoflurane-based anesthesia can reduce the degree of EA and decrease its incidence without increasing the occurrence of adverse reactions in pediatric patients.