ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
Objective:To evaluate the changes in electroencephalogram (EEG) during cognitive dysfunction induced by multiple inhalation of sevoflurane anesthesia in aged rats.Methods:Twenty-one SPF healthy male Sprague-Dawley rats, aged 20-22 months, weighing 450-550 g, were divided into 2 groups using a random number table method: control group (group C, n=8) and repeated inhalation of sevoflurane anesthesia group (group S, n=13). In group S, the rats were put into an anesthesia box and inhaled a mixture of 3% sevoflurane and 30% oxygen for anesthesia, the oxygen flow rate was set at 3 L/min, maintaining for 3 h, and anesthesia was performed once every week for 3 times in total.The rats only inhaled a mixture of 70% air and 30% oxygen in group C. Two weeks later, cognitive function was assessed using Morris water maze test, the EEG was collected and analyzed by the multi-channel physiological signal system, and the recording time of EEG signal was 30 min.The rats were sacrificed, and the brains were collected for determination of the count of apoptotic nerve cells (by TUNEL staining), and the apoptotic rate of nerve cells was calculated. Results:Compared with group C, the escape latency was significantly prolonged at 3rd and 4th days of training, the number of crossing the original platform was decreased at 5th day, the percentage of high-frequency waves was decreased, the percentage of low-frequency waves was increased, and the apoptosis rate of nerve cells was increased in group S ( P<0.05). Conclusion:The percentage of high-frequency waves is decreased, and the percentage of low-frequency waves is increased during cognitive dysfunction induced by multiple inhalation of sevoflurane anesthesia, which may be related to apoptosis in nerve cells of aged rats.
ABSTRACT
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.
ABSTRACT
Objective:To evaluate the effects of sevoflurane on right ventricular myocardial fibrosis caused by pulmonary arterial hypertension (PAH) in rats.Methods:Eighteen SPF healthy adult male Wistar rats, weighing 260-300 g, were divided into 3 groups ( n=6 each) by a random number table method: control group (group C), group PAH and PAH plus sevoflurane group (group PS). The PAH model was established by single intraperitoneal injection of monocrotaline 60 mg/kg in group PAH and group PS, while the equal volume of normal saline was intraperitoneally injected in group C. Sevoflurane 1.5 MAC was inhaled for 1 h starting from the end of injection, twice a week for 6 weeks in total, in group PS.Echocardiography was performed at the end of 6th week to measure right ventricular end-diastolic diameter (RVEDD), right ventricular anterior wall end-diastolic thickness (RVWTd), interventricular septal end-diastolic thickness (IVSTd), pulmonary artery inner diameter (PAID) and pulmonary valve orifice maximum peak velocity (PV). At the end of 6th week, the hearts were taken to measure the weight of right ventricle, interventricular septum and left ventricle, and Fulton′s index was calculated, and the tissue of the lower lobe of the right lung was taken, the outer diameter and inner diameter of the vascular wall were measured to calculate the vascular wall thickness index (WT), and total vascular area and lumen area were measured to calculate the vascular wall area index (WA) after HE staining.The myocardial tissue of the right ventricle was obtained to observe the degree of myocardial fibrosis (with a light microscope after Masson staining) and to detect the expression of TGF-β1 (after immunofluorescence staining) and expression of TGF-β1, phosphorylated Smad3 (p-SMad3) and Smad7 (by Western blot). Results:Compared with group C, Fulton′s index, RVEDD, RVWTd, IVSTd, PAID, WT and WA were significantly increased, PV was decreased, the expression of TGF-β1 and pSmad3 in right ventricular myocardial tissues was up-regulated, the expression of Smad7 was down-regulated( P<0.01), and myocardial fibrosis occurred in group PAH.Compared with group PAH, Fulton′s index, RVEDD, RVWTd, IVSTd, PAID, WT and WA were significantly decreased, PV was increased, the expression of TGF-β1 and pSmad3 in right ventricular myocardial tissues was down-regulated, the expression of Smad7 was up-regulated ( P<0.05 or 0.01), and myocardial fibrosis was significantly improved in group PS. Conclusion:Sevoflurane can improve the myocardial fibrosis in right ventricle induced by PAH in rats, and the mechanism may be related to inhibiting activation of TGF-β1/Smad3 signaling pathway.
ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
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.