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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 role of RhoA/ROCK2 signaling pathway in multiple exposures to sevoflurane-induced long-term cognitive impairment in neonatal rats.Methods:Sixty SPF healthy neonatal Sprague-Dawley rats of either sex, aged 6 days, weighing 12-20 g, were divided into 3 groups ( n=20 each) using a random number table method: control group (group C), multiple exposures to sevoflurane group (group S) and RhoA/ROCK2 signaling pathway inhibitor Y-27632 group (group Y). Group S and group Y inhaled 3% sevoflurane for 2 h at days 6, 7 and 8 after birth.In group Y, Y-27632 5 mg/kg was intraperitoneally injected before sevoflurane anesthesia.The spontaneous activity was evaluated by open field test on day 35 after birth.The cognitive function was detected by Morris water maze test at day 36 after birth.The rats were sacrificed after Morris water maze test, and the hippocampal tissues were isolated for determination of the apoptosis rate of hippocampal neurons and cytoplasmic calcium concentration ([Ca 2+ ] i) (by flow cytometry) and expression of phosphorylated RhoA (p-RhoA), ROCK2 and cleaved-caspase-3 (by Western blot) and for microscopic examination of the ultrastructure of hippocampal neurons (with a transmission electron microscope). Results:There was no significant difference in movement speed, distance and time of stay in the open field center in the open field test among the three groups ( P>0.05). Compared with group C, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the apoptosis rate of hippocampal neurons and [Ca 2+ ] i were increased, the expression of p-RhoA, ROCK2 and cleaved-caspase-3 was up-regulated ( P<0.05), and the pathological injury to hippocampal neurons was found in group S. Compared with group S, the escape latency was significantly shortened, the number of crossing the original platform was increased, the apoptosis rate of hippocampal neurons and [Ca 2+ ] i were decreased, the expression of p-RhoA, ROCK2 and cleaved-caspase-3 was down-regulated ( P<0.05), and the pathological injury to hippocampal neurons was attenuated in group Y. Conclusions:The mechanism by which multiple exposures to sevoflurane induces long-term cognitive impairment is related to activation of RhoA/Rock2 signaling pathway and induction of apoptosis rate of hippocampal neurons in neonatal rats.
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Objective:To evaluate the role of N-methyl-D-aspartate receptors (NMDA receptors) in sevoflurane anesthesia-caused necroptosis in hippocampal neurons of aged mice.Methods:Ninety clean-grade healthy male C57BL/6 mice, aged 18 months, weighing 27-30 g, were divided into 3 groups ( n=30 each) using a random number table method: control group (group C), sevoflurane anesthesia group (group S) and sevoflurane anesthesia plus NMDA receptor antagonist memantine hydrochloride group (group S+ M). Mice inhaled 3% sevoflurane for 2 h for 3 consecutive days in S group and S+ M group, and memantine hydrochloride 20 mg/kg was intraperitoneally injected at 1 h before each inhalation of sevoflurane in S+ M group.Mice only inhaled pure oxygen for 2 h in group C. Ten mice of each group were selected on 1 day before anesthesia and 3 and 7 days after anesthesia to perform Morris water maze test.The mice were sacrificed immediately after Morris water maze test, and hippocampus was removed for microscopic examination of pathological changes (with a light microscope) and for determination of the necroptosis rate of neurons and cytoplasmic free calcium concentration([Ca 2+ ] i)(by flow cytometry), and expression of NMDA receptor subtypes GluN2A, GluN2B and receptor-interacting protein kinase 1 (RIP1) (by Western blot). Results:Compared with group C, the escape latency was significantly prolonged, and the frequency of crossing the original platform was decreased, and the [Ca 2+ ] i and neuronal necroptosis rate in the hippocampus were increased at each time point after anesthesia, and the expression of GluN2A, GluN2B and RIP1 was up-regulated( P<0.05), and the pathologic changes were accentuated in S group and S+ M group.Compared with group S, the escape latency was significantly shortened, and the frequency of crossing the original platform was increased, and the [Ca 2+ ] i and neuronal necroptosis rate in the hippocampus were decreased at each time point after anesthesia, and the expression of GluN2A, GluN2B and RIP1 was down-regulated ( P<0.05), and the pathologic changes were attenuated in group S+ M. Conclusions:NMDA receptors are involved in the process of cognitive dysfunction induced by sevoflurane anesthesia in aged mice, and the mechanism may be related to the promotion of necrptosis in hippocampal neurons.
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Objective:To evaluate the role of brain-derived neurotrophic factor (BDNF)/tropomyosin-related kinase B (TrkB) signaling pathway in pre-injection of young rat plasma-induced reduction of sevoflurane-caused cognitive dysfunction in aged rats.Methods:Eighty SPF healthy male Sprague-Dawley rats, aged 18 months, weighing 550-650 g, were divided into 4 groups ( n=20 each) using a random number table method: control group (group C), sevoflurane anesthesia group (group S), young rat plasma group (group Y) and BDNF/TrkB signaling pathway inhibitor K252a group (group K). The plasma 100 μl obtained from 3-month-old young rats was injected via the tail vein in group Y and group K, while the equal volume of normal saline was given via the tail vein in group C and group S, twice a week, for 4 weeks.In S, Y and K groups, 3% sevoflurane was inhaled for 3 h starting from the end of treatment, and BDNF/TrkB signaling pathway inhibitor K252a was injected via the tail vein before anesthesia in group K. The open field test and Morris water maze test were performed at 3 days after anesthesia to assess the spontaneous motor ability and cognitive function.Then the rats were sacrificed, and the hippocampal tissues were isolated for determination of the expression of BDNF, phosphorylated TrkB (p-TrkB), postsynaptic dense protein-95 (PSD-95) and synaptic vesicle protein (SYN) (by Western blot), dendritic length and dendritic ridge density of neurons in hippocampal CA1 area (by Golgi staining), and the number of synapses and length of synaptic active area (with a transmission electron microscope). Results:Compared with group C, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the expression of p-TrkB, BDNF, PSD-95 and SYN was down-regulated, and the dendritic length, dendritic ridge density, the number of synapses and length of synaptic active area were decreased in group S ( P<0.05). Compared with group S, the escape latency was significantly shortened, the number of crossing the original platform was increased, the expression of p-TrkB, BDNF, PSD-95 and SYN was up-regulated, and the dendritic length, dendritic ridge density, the number of synapses and length of synaptic active area were increased in group Y ( P<0.05). Compared with group Y, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the expression of p-TrkB, BDNF, PSD-95 and SYN was down-regulated, and the dendritic length, dendritic ridge density, the number of synapses and length of synaptic active area were decreased in group K ( P<0.05). Conclusions:The mechanism by which pre-injection of young rat plasma reduces sevoflurane-induced cognitive dysfunction is related to activation of BDNF/TrkB signaling pathway and improvement in synaptic plasticity in the hippocampus of aged rats.
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Objective:To evaluate the effect of sevoflurane on necroptosis in isolated hippocampal neurons and the relationship with ryanodine receptor.Methods:Primarily cultured hippocampal neurons of fetal rats of Sprague-Dawley rats were inoculated in culture wells (100 μl/well) or culture flasks (3 ml/bottle) at a density of 5×10 5 cells/ml at 7 days of culture and divided into 3 groups ( n=24 each) using a random number table method: control group (group C), sevoflurane group (group S) and ryanodine receptor antagonist group (group R). Group C received routine culture.Ryanodine receptor antagonist Dantrolene at a final concentration of 3 μmol/L was added in group R. Thirty minutes later, the cells were placed in the incubator containing 2% sevoflurane and cultured for 5 h at 37 ℃ in S and R groups.Then cells were collected, the morphology of neurons was observed with an inverted microscope, the concentrations of free calcium ion ([Ca 2+ ] i) in cytoplasm were determined by flow cytometry, the expression of ryanodine receptor and phosphorylated MLKL protein (p-MLKL) was detected by Western blot, the expression of RIP3 was measured by immunofluorescence, and necroptosis rate was calculated. Results:Compared with group C, the [Ca 2+ ] i were significantly increased, the expression of ryanodine receptor and p-MLKL was up-regulated, and the necroptosis rate was increased in S and R groups ( P<0.05). Compared with group S, the expression of ryanodine receptor and p-MLKL was significantly down-regulated, and the [Ca 2+ ] i and necroptosis rate were decreased in group R ( P<0.05). There was no obvious abnormality in the morphology of neurons in group C. The cell body of neurons were shrunk, the processes were broken, and the network between processes was sparse in group S. The cell body was round, and the morphology was close to normal in group R. Conclusion:Sevoflurane can cause necroptosis in isolated hippocampal neurons of rats, and the mechanism is related to up-regulating the expression of ryanodine receptors and leading to calcium overload.
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Objective:To evaluate the role of reactive oxygen species (ROS)-mediated mitochondrial pathway of apoptosis in long-term cognitive impairment induced by multiple exposures to sevoflurane in the neonatal rats.Methods:Sixty SPF healthy neonatal Sprague-Dawley rats, weighing 12-20 g, were divided into 3 groups ( n=20 each) using a random number table method: control group (group C), multiple exposures to sevoflurane for anesthesia group (group S) and ROS inhibitor group (group A). Group S and group A inhaled 3% sevoflurane for 2 h starting from 6, 7 and 8 days after birth, while group C inhaled air.In group A, ROS inhibitor N-acetylcysteine (NAC) 150 mg/kg was intraperitoneally injected before each anesthesia with sevoflurane.The spontaneous activity was evaluated by open field test on day 35 after birth.The cognitive function was determined by Morris water maze test on day 36 after birth.The rats were sacrificed after the end of Morris water maze test, and the hippocampal tissues were obtained for determination of the apoptosis rate of hippocampal neurons, reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) (by flow cytometry) and levels of Cyt c and cleaved caspase-9 and caspase-3 (by Western blot). The expression of Bcl-2 and Bax mRNA was detected by real-time polymerase chain reaction.The ultrastructure of mitochondria in hippocampal neurons was observed with a transmission electron microscope. Results:Compared with group C, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the apoptosis rate of hippocampal neurons and levels of ROS and MMP were increased, the expression of Cyt c, cleaved caspase-9, cleaved caspase-3 and Bax mRNA was up-regulated, the expression of Bcl-2 mRNA was down-regulated, the ratio of Bax/Bcl-2 was increased ( P<0.05), mitochondria were swollen, and mitochondrial cristae structure was broken in group S. Compared with group S, the escape latency was significantly shortened, the number of crossing the original platform was increased, the apoptosis rate of hippocampal neurons and levels of ROS and MMP were decreased, the expression of Cyt c, cleaved caspase-9, cleaved caspase-3 and Bax mRNA was down-regulated, the expression of Bcl-2 mRNA was up-regulated, the ratio of Bax/Bcl-2 was decreased ( P<0.05), and the mitochondrial swelling and rupture of cristae structure were improved in group A. Conclusion:The mechanism by which multiple exposures to sevoflurane induce long-term cognitive impairment may be related to activating the ROS-mediated mitochondrial pathway of apoptosis in neonatal rats.
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Objective:To evaluate the effect of pre-infusion of young rat plasma on cognitive dysfunction induced by sevoflurane in aged rats and the role of extracellular regulated protein kinase (ERK)-cyclic adenosine monophosphate effector binding protein (CREB) signaling pathway.Methods:One hundred and twenty SPF healthy male Wistar rats, aged 18 months, weighing 550-650 g, were divided into 4 groups ( n=30 each) using a random number table method: control group (group C), sevoflurane anesthesia group (group S), young rat plasma group (group P) and ERK inhibitor SL327 group (group SL). The teated plasma 100 μl from 3-month-old young rats was injected via the tail vein in group P and group SL, while the equal volume of normal saline was given via the tail vein in group C and group S, twice a week, for 4 weeks.In S, P and SL groups, 3% sevoflurane was inhaled for 3 h at the end of injection, and ERK inhibitor SL327 50 mg/kg was injected via the tail vein before anesthesia in group SL.The cognitive function was evaluated by Morris water maze test at 1 day before anesthesia and at 3 and 7 days after anesthesia.The rats were sacrificed, and their hippocampi were isolated for determination of the expression of phosphorylated ERK (p-ERK), p-CREB, synapsin, synapsin Ⅰ and synaptophysin and for examination of the ultrastructure of neurons (by transmission electron microscopy). The number of synapses was recorded. Results:Compared with group C, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the expression of p-ERK, p-CREB, synapsin, synapsin Ⅰ and synaptophysin was down-regulated, and the number of synapses was decreased at each time point after anesthesia in the other 3 groups ( P<0.05). Compared with group S, the escape latency was significantly shortened, the number of crossing the original platform was increased, the expression of p-ERK, p-CREB, synapsin, synapsin Ⅰ and synaptophysin was up-regulated, and the number of synapses was increased at each time point after anesthesia in P and SL groups ( P<0.05). Compared with group P, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the expression of p-ERK, p-CREB, synapsin, synapsin Ⅰ and synaptophysin was down-regulated, and the number of synapses was decreased in group SL ( P<0.05). Conclusion:Pre-infusion of young rat plasma can reduce cognitive dysfunction induced by sevoflurane in aged rats, and the mechanism is related to activation of ERK-CREB signaling pathway and improvement of synaptic plasticity.
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Objective:To evaluate the role of interleukin 1β (IL-1β)/c-Jun N-terminal kinase (JNK) pathway in sevoflurane-induced necroptosis of rat hippocampal neurons in vitro. Methods:Primarily cultured hippocampal neurons of Sprague-Dawley rat fetuses were inoculated into 96-well plates (cell density: 1×10 4 cells/ml, 200 μl/hole) and 6-well plates (cell density: 1×10 6 cells/ml, 2 ml/hole). The cells were divided into 3 groups ( n=20 each) using a random number table method after being cultured for 7 days: control group (group C), sevoflurane group (group S) and IL-1 receptor antagonist group (group I). Group C received routine culture, IL-1 receptor antagonist IL-1ra 1 μg/μl was added, and the cells were incubated for 30 min in group I, and in addition the cells were placed in the incubator containing 2% sevoflurane and cultured for 5 h at 37 ℃ in S and I groups.The cells were collected for microscopic examination of the morphology of neurons (with an inverted microscope) and for determination of the cell necroptosis rate (by flow cytometry), cell viability (by MTT method), and expression of IL-1β, interleukin-1 receptor type I (IL-1RI), interleukin-1 receptor accessory protein (IL-1RAcP), phosphorylated JNK (p-JNK) ), receptor-interacting protein 1 (RIP1), RIP3 and phosphorylated mixed lineage kinase-like (p-MLKL) (by Western blot ). Results:Compared with group C, the cell viability was significantly decreased, the necroptosis rate was increased, and the expression of IL-1β, IL-1RI, IL-1RAcP, p-JNK, RIP1, RIP3 and p-MLKL was up-regulated in group S ( P<0.05). Compared with group S, the cell viability was significantly increased, the necroptosis rate was decreased, and the expression of IL-1β, IL-1RI, IL-1RAcP, p-JNK, RIP1, RIP3 and p-MLKL was down-regulated in group I ( P<0.05). There was no obvious abnormality in the morphology of neurons in group C. The cell body of neurons was shrunk, the processes were broken, and the network between processes was sparse in group S. The cell body was round, and the morphology was close to normal in group I. Conclusion:The mechanism by which sevoflurane induces necroptosis of rat hippocampal neurons in vitro is related to activation of IL-1β/JNK pathway.
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Objective:To evaluate the effect of pre-infusion of young rat plasma on postoperative cognitive function in aged rats and role of phosphatidylinositol 3 kinase/serine-threonine protein kinase (PI3K/Akt) signaling pathway.Methods:Sixty SPF healthy male Sprague-Dawley rats, aged 18 months, weighing 550-650 g, were divided into 4 groups ( n=15 each) using a random number table method: control group (group C), operation group (group O), young rat plasma group (group P) and PI3K inhibitor LY294002 group (group LY). The young rat plasma 100 μl/time was injected via the caudal vein twice a week for 4 consecutive weeks in group P and group LY, while the equal volume of normal saline was given instead in group C and group O. Rats received internal fixation for unilateral tibial fracture under sevoflurane anesthesia in O, P and LY groups.Rats received no treatment in group C. PI3K inhibitor LY294002 0.3 mg/kg was injected through the caudal vein before anesthesia in group LY.The ability of spontaneous activity was evaluated by open field test at 3 days after surgery, and then the cognitive function was assessed by Morris water maze test.The rats were sacrificed after the end of behavioral testing, and the hippocampal tissues were isolated for determination of the expression of phosphorylated PI3K (p-PI3K), phosphorylated Akt (p-Akt), synapsin, synaptophysin I and synaptic vesicle protein (by Western blot) and for microscopic examination of the ultrastructure of hippocampal neurons (with a transmission electron microscope). The number of synapses was recorded. Results:There was no significant difference in the movement speed and length and time spent in the central zone among the four groups ( P>0.05). Compared with group C, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the expression of p-PI3K, p-Akt, synapsin, synaptophysin I and synaptic vesicle protein was down-regulated, and the number of synapses was reduced in O and LY groups ( P<0.05), and no significant change was found in the parameters mentioned above in group P ( P>0.05). Compared with group O, the escape latency was significantly shortened, the number of crossing the original platform was increased, the expression of p-PI3K, p-Akt, synapsin, synaptophysin I and synaptic vesicle protein was up-regulated, and the number of synapses was increased in group P ( P<0.05), and no significant change was found in the parameters mentioned above in group LY ( P>0.05). Compared with group P, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the expression of p-PI3K, p-Akt, synapsin, synaptophysin I and synaptic vesicle protein was down-regulated, and the number of synapses was reduced in group LY ( P<0.05). Conclusion:Pre-infusion of young rat plasma can improve postoperative cognitive function in aged rats, and the mechanism is related to activation of PI3K/Akt pathway and improvement of synaptic plasticity.
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Objective To evaluate the effect of nimodipine pretreatment on postoperative cognitive function in rats with chronic cerebral ischemia.Methods Sixty healthy male Sprague-Dawley rats,aged 3 months,weighing 250-350 g,were divided into 2 groups (n =30 each) using a random number table method:chronic cerebral ischemia operation group (group H) and nimodipine plus chronic cerebral ischemia operation group (group N+H).The chronic cerebral ischemia model was established by permanently ligating bilateral common carotid arteries of chloral hydrate-anesthetized rats.Rats underwent Morris water maze adaptive training for 5 days 2 weeks later.Nimodipine 1 mg/kg was intraperitoneally injected on 1st day after the end of adaptive training in group N+H,while the equal volume of normal saline was given instead in group H,and 30 min later splenectomy was performed under sevoflurane anesthesia in two groups.Ten rats in each group were selected on 1 day before operation and 3 and 7 days after operation and underwent Morris water maze test to assess cognitive function.The rats were then sacrificed,brains were removed,and hippocampal tissues were isolated for determination of apoptosis in hippocampal neurons and intracellular Ca2+concentrations([Ca2+]i) in cytoplasm and expression of Bcl-2 and Bax mRNA (by realtime polymerase chain reaction).The ratio of Bax mRNA to Bcl-2 mRNA was calculated.Results Compared with the baseline at 1 day before operation,the escape latency was significantly prolonged,the frequency of crossing the original platform was decreased,the apoptotic rate and [Ca2+] i were increased,Bcl2 mRNA expression was down-regulated,and Bax mRNA expression was up-regulated,and Bax mRNA/Bcl-2 mRNA ratio was increased at each time point after operation in two groups (P＜0.05).Compared with group H,the escape latency was significantly shortened,the frequency of crossing the original platform was increased,the apoptotic rate and [Ca2+]iwere decreased,Bcl-2 mRNA expression was up-regulated,and Bax mRNA expression was down-regulated,and Bax mRNA/Bcl-2 mRNA ratio was decreased at each time point after operation in group N+ H (P＜ 0.05).Conclusion Nimodipine pretreatment can improve the postoperative cognitive function of rats with chronic cerebral ischemia,and the mechanism may be related to inhibiting calcium overload-induced apoptosis in hippocampal neurons.
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Objective To evaluate the effect of laparotomy on cognitive function in rats with trau-matic brain injury and the relationship with calcium overload. Methods One hundred and fifty healthy male Wistar rats,aged 2~3 months,weighing 190~220 g,were assigned into 5 group ( n=30 each) using a ran-dom number table:blank group(group B),surgery group of blank rats(group BS),surgery group of sham rats (group SS),traumatic brain injury rats group( group T),surgery group of traumatic brain injury rats(group TS). TBI model was made in rats of group T and TS by Feeney method. Rats in group SS were only treated with cranial bone window without crainocerebral impact. Both group B and BS were normal rats. Then the rats in group BS,SS and TS group underwent laparotomy under sevoflurane anesthesia (the operation time was a-bout 3 hours) and the rats in group B and T inhaled pure oxygen for 3 hours after 20 days. One day before surgery,3 and 7 d after surgery,10 rats in each group were randomly selected for Morris water maze test. The hippocampus tissue of 10 rats were taken after the water maze test. The apoptosis rate and calcium concen-tration of hippocampal neurons were measured by flow cytometry,and the expression level of cleaved caspase-3 in hippocampal tissues was determined by Western blot. Results One day before surgery,compared with group B(the escape latency(9. 8±0. 8)s,the number of crossing platform (5. 8±0. 8),the apoptosis rate of hippocampal neurons ( 2. 5 ± 0. 9)%, calcium ion concentration ( 2. 3 ± 0. 2),the expression of cleaved caspase-3 (0. 22±0. 07) ),the escape latency of group T and group TS were prolonged (group T:(25. 5± 0. 7)s,P<0. 05;group TS:(25. 1±1. 1) s,P<0. 05),the number of crossing platform decreased (group T:(2. 7±0. 8),P<0. 05;group TS:(2. 8±0. 6),P<0. 05),the apoptosis rate of hippocampal neurons increased (group T:(5. 3±0. 6)%,P<0. 05;group TS:(5. 2±1. 0)%,P<0. 05),calcium ion concentration increased (group T:(3. 7±0. 4),P<0. 05;group TS:(3. 6±0. 5),P<0. 05) and the expression of cleaved caspase-3 increased (group T:(0. 45±0. 07),P<0. 05;group TS:(0. 44±0. 05),P<0. 05),the differences were statis-tically significant. Compared with the group SS,the escape latency ( 3 d after surgery:group SS:( 23. 8 ± 1. 3)s,group TS:(56. 4±2. 5)s,P<0. 05;7 d after surgery:group SS:(16. 6±1. 8)s,group TS:(38. 1±2. 1) s,P<0. 05)of the rats in group TS were prolonged,the number of crossing platform decreased (3 d after sur-gery:group SS:(2. 9±0. 6) ,group TS:(1. 1±1. 1) ,P<0. 05;7 d after surgery:group SS:( 4. 2± 1. 2) , group TS:(1. 7±1. 3),P<0. 05),the apoptosis rate of hippocampal neurons ( 3 d after surgery:group SS:(4. 8±0. 6)%,group TS:(14. 4± 0. 6)%,P<0. 05;7 d after surgery:group SS:(3. 8± 1. 1)%,group TS:(9. 6±1. 3)%,P<0. 05),calcium ion concentration ( 3 d after surgery:group SS:(3. 1± 0. 3),group TS:(6. 4±0. 5),P<0. 05;7 d after surgery:group SS:( 2. 6± 0. 3),group TS:( 4. 8± 0. 4),P<0. 05) ,the ex-pression of cleaved caspase-3 (3 d after surgery:group SS:( 0. 42± 0. 03),group TS:( 0. 88 ± 0. 08),P<0. 05;7 d after surgery:group SS:(0. 33±0. 05),group TS:(0. 63±0. 06),P<0. 05) in the hippocampus in-creased after surgery (P<0. 05). Compared with the T group,the escape latency (3 d after surgery:group T:( 18. 6±2. 0)s,group TS:(56. 4±2. 5)s,P<0. 05;7 d after surgery:group T:(13. 8±2. 6)s,group TS:(38. 1 ±2. 1)s,P<0. 05) of the rats in group TS were prolonged,the number of crossing platform (3 d after surger-y:group T:(3. 4±0. 5),group TS:(1. 1±1. 1),P<0. 05;7 d after surgery:group T:(4. 3±1. 2),group TS:(1. 7±1. 3),P<0. 05) decreased,the apoptosis rate of hippocampal neurons (3 d after surgery:group T:(4. 4±0. 7)%,group TS:( 14. 4 ± 0. 6)%,P<0. 05;7 d after surgery:( 3. 3 ± 1. 3)%,group TS:( 9. 6 ± 1. 3)%,P<0. 05),calcium ion concentration (3 d after surgery:group T:( 3. 4 ± 0. 4),group TS:( 6. 4 ± 0. 5),P<0. 05;7 d after surgery:group T:(3. 0±0. 3),group TS:(4. 8±0. 4),P<0. 05),the expression of cleaved caspase-3 (3 d after surgery:group T:(0. 40±0. 04),group TS:( 0. 88±0. 08),P<0. 05;7 d after surgery:(0. 35±0. 02),group TS:(0. 63±0. 06),P<0. 05) in the hippocampus increased after surgery(P<0. 05). Conclusion Laparotomy can aggravate the cognitive impairment of rats with traumatic brain injury and cause postoperative cognitive impairment,which may be related to the increased degree of calcium over-load and the increased rate of hippocampal neuron apoptosis.
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Objective To evaluate the effect of nimodipine pretreatment on postoperative cognitive function in rats with cerebral ischemic stroke.Methods Sixty healthy male Sprague-Dawley rats,aged 3 months,weighing 250-350 g,were divided into 2 groups (n =30 each) using a random number table method:normal saline plus cerebral ischemic stroke group (group Ⅰ) and nimodipine plus cerebral ischemic stroke group (group N+Ⅰ).The cerebral ischemic stroke model was established by thread occlusion in two groups.Three weeks later,nimodipine 1 mg/kg was intraperitoneally injected in group N+Ⅰ,while the equal volume of normal saline was given instead in group Ⅰ,and 30 min later two groups underwent exploratory laparotomy under 1.7％ sevoflurane anesthesia.Eight rats in each group were randomly selected on 1 day before operation and 3 and 7 days after operation,and Morris water maze test was performed to assess cognitive function.The rats were then sacrificed,brains were removed,and hippocampal tissues were isolated for detection of apoptosis in hippocampal neurons,intracellular Ca2+concentration ([Ca2+]i) in cytoplasm and the expression of Bcl-2 and Bax mRNA (by real-time polymerase chain reaction).The ratio of Bax mRNA to Bcl-2 mRNA was calculated.Results Compared with the value at 1 day before operation,the escape latency was significantly prolonged,the frequency of crossing the original platform was decreased,apoptotic rate and [Ca2+] i were increased,Bcl-2 mRNA expression was down-regulated,Bax mRNA expression was up-regulated,and Bax mRNA/Bcl-2 mRNA ratio was increased at each time point after operation in two groups (P＜0.05).Compared with group Ⅰ,the escape latency was significantly shortened,the frequency of crossing the original platform was increased,the apoptotic rate and [Ca2 +]i were decreased,Bcl-2 mRNA expression was up-regulated,Bax mRNA expression was down-regulated,and Bax mRNA/Bcl-2 mRNA ratio was decreased at each time point after operation in group N+Ⅰ (P＜0.05).Conclusion Nimodipine pretreatment can improve the postoperative cognitive function of rats with cerebral ischemic stroke,and the mechanism may be related to inhibiting calcium overload-induced apoptosis in hippocampal neurons.
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Objective To evaluate the effect of nimodipine on the activity of calcineurin (CaN) in the hippocampus of aged rats.Methods Sixty healthy male Sprague-Dawley rats,aged 18 months,weighing 550-650 g,were divided into 2 groups (n=30 each) using a random number table:surgery group (group S) and nimodipine group (group N).Nimodipine 1 mg/kg was intraperitoneally injected in group N,while the cqual volume of normal saline was given instead in group S,and 30 min later exploratory laparotomy was performed.Ten rats in each group were randomly selected on 1 day before operation and 3 and 7 days after operation,and Morris water maze test was performed.After the end of Morris water maze test,10 rats were selected and sacrificed,brains were removed,and hippocampi were isolated for detection of apoptosis in hippocampal neurons (by flow cytometry) and expression of CaN,phosphor-BAD (p-BAD) and caspase-3 in hippocampal tissues (by Western blot).Apoptotic rate was calculated.Results Compared with the value at 1 day before operation,the escape latency was significantly prolonged,the frequency of crossing the original platform was decreased,the time of staying at the platform quadrant was shortcned,apoptotic rate was increased,and the expression of CaN,p-BAD and caspase-3 in hippocampal tissues was up-regulated at each time point after operation in group S (P＜0.05).Compared with group S,the escape latency was significantly shortened,the frequency of crossing the original platform was increased,the time of staying at the platform quadrant was prolonged,apoptotic rate was decreased,and the expression of CaN,p-BAD and caspase-3 in hippocampal tissues was down-regulated at each time point after operation in group N (P＜0.05).Conclusion The mechanism by which nimodipine inhibits apoptosis in hippocampal neurons and reduces postoperative cognitive dysfunction may be related to inhibition of CaN activation in aged rats.
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Objective To evaluate the effect of nimodipine combined with 7.5％ hypertonic saline (HS) on postoperative cognitive function in aged rats.Methods Ninety-six healthy male Wistar rats,aged 18 months,weighing 450-500 g,were assigned into 4 groups (n=24 each) using a random number table:splenectomy group (group S),nimodipine group (group N),group HS and nimodipine plus HS group (group N+HS).Nimodipine 1 mg/kg was intraperitoneally injected in group N.In group HS,7.5％ HS 4 ml/kg was injected via the caudal vein.The equal volume of normal saline was injected intraperitoneally or via the caudal vein in group S.Splenectomy was performed under sevoflurane anesthesia at 30 min after the end of administration.On 1 day before operation and 3 and 7 days after operation,Morris water maze test was performed,and blood sainples from the caudal vein were simultaneously collected for determination of the concentrations of serum S100β protein and neuron-specific enolase (NSE) by enzyme-linked immunosorbent assay.Results Compared with group S,the frequency of crossing the original platform was significantly increased,the escape latency was shortened,and the concentrations of serum S100β protein and NSE were decreased at each time point after operation in N,HS and N+HS groups (P＜0.05).Compared with group N or group HS,the frequency of crossing the original platform was significantly increased,the escape latency was shortened,and the concentrations of serum S100β protein and NSE were decreased at each time point after operation in group N+HS (P＜0.05).Conclusion Nimodipine combined with 7.5％ HS exerts better efficacy than either alone in improving postoperative cognitive function in aged rats.
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Objective To observe the influence of Zhenweifang on the muscle tension in flaccid paralysis period and prognosis of stroke.Methods One hundred and eighty patients were randomly divided into basic group,Buyanghuanwutang group and Zhenweifang group.Basic group was treated with usual medical treatment with nerve rehabitilation and acupuncture.Buyanghuanwutang group and Zhenweifang group were given the corresponding traditional Chinese medicine.Patients in Buyanghuanwutang group and Zhenweifang group stop taking the traditional Chinese medicine when their muscle tension reach the level of Ashworth Grade Ⅱ,and continued their basic treatment.The defect of neurological and daily life ability were evaluated after three-week and six-week treatment,and the prognosis was evaluated according to clinical efficacy.Results The time that patients muscle tension in Zhenweifang group need to reach Ashworth Grade Ⅱ was much shorter than that in Buyanghuanwutang group and basic group(P
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To investigate the role of ligustrazine on relaxation of the isolated rabbit corpus cavernosum tissue in vitro, the effects of ligustrazine on the corpus cavernosum were observed by using experimental method of smooth muscle strips. Concentration-responses to phenylephine (PE) and KCl were recorded. The results showed that ligustrazine concentration-dependently depressed the contraction response of smooth muscle strips induced by PE. The maximum percentage relaxation of cavernosal strips by ligustrazine was 74.1% ±6.2 % (compared with control: 21.9 % ±5.6 %, P ＜0.01). Ligustrazine concentration-dependently reduced the amplitude of the contraction induced by cumulative doses of PE or KCl, shifted the cumulative concentration response curves of PE and KCl to the right and depressed their maximal responses. It was concluded that ligustrazine could significantly relax the cavernosal muscle contraction induced by PE in vitro. The results suggested that ligustrazine inhibited calcium ion influx.
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To investigate the role of ligustrazine on relaxation of the isolated rabbit corpus cavernosum tissue in vitro, the effects of ligustrazine on the corpus cavernosum were observed by using experimental method of smooth muscle strips. Concentration-responses to phenylephine (PE) and KCl were recorded. The results showed that ligustrazine concentration-dependently depressed the contraction response of smooth muscle strips induced by PE. The maximum percentage relaxation of cavernosal strips by ligustrazine was 74.1% +/- 6.2% (compared with control: 21.9% +/- 5.6%, P < 0.01). Ligustrazine concentration-dependently reduced the amplitude of the contraction induced by cumulative doses of PE or KCl, shifted the cumulative concentration response curves of PE and KCI to the right and depressed their maximal responses. It was concluded that ligustrazine could significantly relax the cavernosal muscle contraction induced by PE in vitro. The results suggested that ligustrazine inhibited calcium ion influx.
Subject(s)
Calcium Channels/drug effects , Muscle Contraction/drug effects , Muscle Relaxation/drug effects , Muscle, Smooth/drug effects , Muscle, Smooth/physiology , Penis/drug effects , Penis/physiology , Phenylephrine/pharmacology , Potassium Chloride/pharmacology , Pyrazines/pharmacologyABSTRACT
<p><b>OBJECTIVE</b>To investigate the effects of chuanxiongzine on the relaxation of isolated rabbit corpus cavernosum tissues.</p><p><b>METHODS</b>Observations were made on the relaxing effect of chuanxiongzine on phenylephrine (PE)-precontracted corpus cavernosum and cavernosal strips preincubated with L-NAME, and ODQ, using endothelium removal and experimental method of smooth muscle strips. The effect of chuanxiongzine on cAMP and cGMP levels in corpus cavernosum was measured by 125I radioimmunoassay.</p><p><b>RESULTS</b>Chuanxiongzine had concentration-dependent relaxing effect on the cavernosal muscle contraction induced by PE (EC50 1.58 x 10(-4) mol/L). This relaxing effect was partially antagonized by ODQ and not blocked by L-NAME or endothelium removal. In PE-precontracted cavernosal strips, chuanxiongzine induced relaxation accompanied with an increase in cAMP and cGMP levels.</p><p><b>CONCLUSION</b>Chuanxiongzine was effective in relaxing cavernosal muscle precontracted by PE in vitro. And its relaxing effect may be enhanced by increasing cGMP and cAMP levels in the corpus cavernosum.</p>
Subject(s)
Animals , Male , Rabbits , Cyclic AMP , Metabolism , Cyclic GMP , Metabolism , Dose-Response Relationship, Drug , In Vitro Techniques , Muscle Relaxation , Muscle, Smooth , Physiology , Penis , Physiology , Pyrazines , PharmacologyABSTRACT
AIM: To study the effects of calcium channel blockers (CCB) on nicotinic acetylcholine receptor current (I_(NIC)) in rat adrenal medullar chromaffin cells (RAMCs). METHODS: By using the whole-cell clamp-patch technique, we have investigated the effects of nifedipine(NIF)、?-conotoxin GVIA and ?-agatoxin IVA on I_(NIC) induced by nicotine(NIC) before and after RAMCs perfusion. RESULTS: After perfusing RAMCs for 5 min, different kinds of calcium channel blockers at different concentration showed significant inhibitory effects on I_(NIC) induced by 50 ?mol/L NIC. The peak inhibition rates of 10 ?mol/L NIF、400 nmol/L ?-conotoxin GVIA and 100 nmol/L ?-agatoxin IVA were (61.7?5.1)%,(29.3?7.4)% and (17.6?7.5)%, respectively. CONCLUSION: The acute effects of different kinds of CCBs on RAMC were that they obviously inhibited I_(NIC) induced by NIC. These results suggest that CCBs may inhibit catecholamine secretion by directly blocking nicotinic acetylcholine receptor channel. [
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By using the whole-cell clamp-patch technique, the effects of dexamethasone on calcium channel current (Ica) and nicotine receptor channel current (I_(NIC)) were examined. The acute action of glucocorticoid on adrenal medullary chromaffin cell (AMCC) of rats was a significant inhibition of I_(NIC), while no apparent effect was observed on Ica induced by electricity. The results suggest that the acute action of glucocorticoid on catecholamine release in rat AMCC may be directly related to nicotine receptor.