Objective To investigate the effect of hyperbaric oxygen on the expression of fractalkine (FKN) in the nerve tissues of rats with neuropathic pain (NP).Methods Thirty-two male Sprague-Dawley rats, weighing 250-280 g, aged 10-12 weeks, were divided into 4 groups (n=8 each) using the random number table: control group (group C), sham operation group (group S), group NP, and hyperbaric oxygen group (group H).NP was induced by chronic constriction injury (CCI) in anesthetized rats.The left sciatic nerve was exposed, and 4 loose ligatures were placed on the sciatic nerve at 1 mm intervals with 4-0 silk thread.Group H received hyperbaric oxygen therapy once a day for 5 consecutive days starting from day 1 after CCI.The rats were placed into the hyperbaric oxygen chamber, which was pressurised to 2 atmosphere absolute at a rate of 10 kPa/min, and maintained at this level for 60 min.The pressure was then decreased to the normal pressure at a rate of 10 kPa/min.The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured at 1 day before CCI, and 3, 5, 7 and 14 days after CCI.After measurement of pain threshold at 3 and 7 days after CCI, 4 rats were selected and sacrificed.The sciatic nerve and lumbar segment of the spinal cord were removed for determination of the expression of FKN by Western blot.Results Compared with group C, the MWT was significantly decreased, and TWL was shortened at each time point after CCI, the expression of FKN in the sciatic nerve at 3 days after CCI, and in the sciatic nerve and spinal cord at 3 and 7 days after CCI was upregulated in group NP (P＜0.05) , and no significant change was found in the parameters mentioned above in group S (P＞0.05).Compared with group NP, the MWT was significantly increased, and TWL was prolonged at each time point after CCI, and the expression of FKN in the sciatic nerve at 3 days after CCI, and in the sciatic nerve and spinal cord at 3 and 7 days after CCI was down-regulated in group H (P＜0.05).Conclusion The mechanism by which hyperbaric oxygen mitigates NP is related to inhibition of over-expression of FKN in the nerve tissues of rats.

Objective To evaluate the effect of hyperbaric oxygen (HBO) treatment on the expression of nerve growth factor (NGF) in the spinal cord of rats with neuropathic pain (NP).Methods Thirty healthy male Sprague-Dawley rats,aged 8-10 weeks,weighing 270-300 g,were randomly divided into 5 groups (n =6 each) using a random number table:sham operation group (group S),group NP,pure oxygen group (group O),treatment with HBO at 2.5 atmosphere absolute group (group H2.5) and treatment with HBO at 3.0 atmosphere absolute group (group H3.0).The animals were anesthetized with intraperitoneal 10％ chloral hydrate 300 mg/kg.NP was induced by chronic constrictive injury.The left sciatic nerve was exposed and 4 loose ligatures were placed on the sciatic nerve at 1-mm intervals with 4-0 silk thread.HBO treatment was performed with the corresponding atmosphere absolute once a day for 7 consecutive days starting from 1 day after operation in H2.5 and H3.0 groups.The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured on 3,5,7 and 14 days after operation.The animals were sacrificed after the last measurement of pain threshold,and the lumbar segments of the spinal cord were removed to detect the expression of NGF by immuno-histochemistry and Western blot analysis.Results Compared with group S,MWT was significantly decreased,TWL was shortened,and the expression of NGF was up-regulated at each time point after operation in NP and O groups.Compared with group NP,MWT was significantly increased,TWL was prolonged,and the expression of NGF was up-regulated at each time point after operation in H2.5 and H3.0 groups,and no significant change was found in MWT,TWL and expression of NGF in group O.Compared with group H2.5,the expression of NGF was significantly down-regulated,and no significant change was found in MWT and TWL in group H3.0.Conclusion The mechanism by which HBO treatment mitigates NP is related to up-regulation of the expression of NGF in the spinal cord of rats.

Objective To evaluate the effect of dexmedetomidine on the expression of brain-derived neurotrophic factor (BDNF) during lidocaine-induced spinal neurotoxicity in rats.Methods Fifty-six male Sprague-Dawley rats,weighing 250-280 g,aged 2-3 months,were divided into 7 groups (n =8 each) using a random number table:sham operation group (group S),lidocaine group (group L),normal saline group (group NS),3 different doses of dexmedetomidine groups (D1,D2 and D3 groups),and oα2-adrenoceptor antagonist yohimbine group (group Y).An epidural catheter was placed at L5.6 interspace.Ten percent lidocaine 20 μl was injected intrathecally in all groups except group S.Dexmedetomidine 5,15 and 25 μg/kg were injected intraperitoneally at 30 min before lidocaine injection in D1,D2 and D3 groups,respectively.In group Y,yohimbine 1.0 mg/kg was injected intraperitoneally at 15 min before dexmedetomidine 25 μg/kg was injected.Before intrathecal administration and at 24,48 and 72 h after intrathecal administration (T1-4),the Basso,Beattie,Bresnahan (BBB) Locomotor Rating Scale was used,and the tail flick latency to a thermal nociceptive stimulus (TFL) was measured to assess the locomotor function.The rats were sacrificed after the last behavioral test,and the lumbar segments (L3-5) of the spinal cord were removed for pathological examination and for determination of BDNF expression and cell apoptosis.The apoptosis index was calculated.Results Compared with group S,the BBB score was significantly decreased at T2-4,the TFL was prolonged,the BDNF expression was up-regulated,and apoptosis index was increased in L,NS,D1,D2 and D3 groups (P＜0.05).Compared with group L,the BBB score was significantly increased at T2-4,the TFL was shortened,the BDNF expression was up-regulated,and apoptosis index was decreased in group D3 (P＜0.05),and no significant change was found in the parameters mentioned above in NS,D1,D2 and Y groups (P＞0.05).Compared with group D3,the BBB score was significantly decreased at T2 4,the TFL was prolonged,the BDNF expression was down-regulated,and apoptosis index was increased in group Y (P＜0.05).The pathological changes of the spinal cord were significantly attenuated in group D3 as compared with group L,and there was no significant difference in pathological changes of the spinal cord between group Y and group L.Conclusion The mechanism by which dexmedetomidine reduces lidocaine-induced spinal neurotoxicity may be related to up-regulation of BDNF expression,and the mechanism by which dexmedetomidine up-regulates BDNF expression is completely related to activation of α2-adrenoceptors in rats.

Objective To determine the minimum alveolar concentration (MAC) of sevoflurane in Chinese neonates.Methods Thirty ASA Ⅰ or Ⅱ neonates,aged ≤ 28 days,with normal body weight,scheduled for elective surgery under general anesthesia,were enrolled in the study.Anesthesia was induced with inhalation of 6.00％ sevoflurane in oxygen.The infants were tracheal intubated and mechanically ventilated.The inhaled concentration of sevoflurane was adjusted to achieve the preset end-tidal concentration and maintained at this level for 20 min.Skin incision was then performed.The concentration of sevoflurane was determined by modified Dixon's up-and-down method.The initial end-tidal concentration of sevofluren was 3.00％.Each time the concentration increased/decreased by 0.25 ％ in the next infant according to the infant's response.Successful skin incision was defined as no body movement during skin incision.The MAC,ED95 and 95 ％ confidence interval of sevoflurane were calculated using logistic regression analysis.Results The MAC and ED95 (95 ％ confidence interval) of sevoflurane required for successful skin incision were 2.82％ (2.66％-2.98％) and 3.39％ (2.89％-3.89％),respectively,in neonates.Conclusion The MAC of sevoflurane is 2.82 ％ in Chinese neonates and lower than the present reference values previously described in foreign reports.

Objective To evaluate the relationship between annexin 1 (ANXA1) and the endogenous protective mechanism during intestinal epithelial cell injury induced by endotoxiu.Methods The intestinal epithelial cells at the logarithmic growth phase were seeded in culture palates and randomly divided into 4 groups (n =36 each) using a random number table:control group (group C),cell injury group (group I),ANXA1 overexpression group (group OE),and ANXA1 silencing group (group S).Lentivirus with ANXA1 overexpression and silencing was transfected into intestinal epithelial cells to construct a stable cell line.In I,OE and S groups,endotoxin was added with the final concentration of 100 μg/ml,and the cells were then incubated for 24 h to establish the cell injury model.The culture medium was changed,and the cells were then incubated for 24 h in group C.The cell apoptosis was detected by flow cytometry,the cell permeability was determined by Transwell assay,and the cell viability was evaluated by methyl thiazolyl tetrazolium assay.The apoptosis rate was calculated.Results Compared with group C,the apoptosis rate was significantly increased,and the cell permeability and viability were significantly decreased in I,OE and S groups (P＜0.05).Compared with group Ⅰ,the apoptosis rate was significantly decreased,the cell permeability and viability were significantly increased in group OE,and the apoptosis rate was significantly increased,and the cell permeability and viability were significantly decreased in group S (P＜0.05).Conclusion ANXA1 is involved in the endogenous protective mechanism during intestinal epithelial cell injury induced by endotoxin.

Objective To evaluate the effects of tempol administered via different routes on neuropathic pain (NP) in rats.Methods Thirty-two male Sprague-Dawley rats,weighing 250-280 g,aged 8-10 weeks,were randomly divided into 4 groups (n=8 each) using a random number table:sham operation group (group S),group NP,intrathecal tempol group (group T1),and intraperitoneal tempol group (group T2).Neuropathic pain was induced by chronic constriction injury in chloral hydrate-anesthetized rats.The sciatic nerve was exposed and 4 loose ligatures were placed on the sciatic nerve at 1 mm intervals with 4-0 silk thread.The sciatic nerve was only exposed but not ligated in group S.After successful establishment of the model,a catheter was inserted at L4.5 interspace into the epidural space.In S and NP groups,0.9％ normal saline 20 μl was injected intrathecally,and 0.9％ normal saline 200 μl was injected intraperitoneally once a day for 7 consecutive days.In group T1,tempol 30 μg (in 20 μl of normal saline) was injected intrathecally,and 0.9％ normal saline 200 μl was injected intraperitoneally once a day for 7 consecutive days.In group T2,tempol 30 μg (in 200 μl of normal saline) was injected intraperitoneally,and 0.9％ normal saline 20 μl was injected intrathecally once a day for 7 consecutive days.The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured at 3 days before operation,and at 1,3,5,7,10 and 14 days after operation.The animals were sacrificed after measurement of pain threshold at day 14 after operation.The lumbar segment of the spinal cord was removed to detect malondialdehyde (MDA) content and superoxide dismutase (SOD) activity by enzyme-linked immunosorbent assay.Results Compared with group S,the MWT was significantly decreased,and the TWL was shortened at each time point after operation,the content of MDA in the spinal cord was increased (P＜0.05),and no significant difference was detected in SOD activity in group NP (P＞0.05).Compared with group NP,the MWT was significantly increased at 5,7,10 and 14 days after operation,the TWL was prolonged at 1,3,5,7,10 and 14 days after operation,the content of MDA in the spinal cord was decreased,and the SOD activity was increased in group T1 (P＜0.05),and no significant change was found in the indexes mentioned above in group T2 (P＞0.05).Conclusion Intrathecal tempol can reduce NP in rats,and the mechanism is related to inhibition of lipid peroxidation in the spinal cord.

Objective To evaluate the effect of hyperbaric oxygen (HBO) treatment on postoperative cognitive dysfunction (POCD) in rats.Methods Eighteen healthy male Sprague-Dawley rats,weighing 260-290 g,were anesthetized with intraperitoneal 10％ chloral hydrate 350 mg/kg.POCD was induced by injecting Aβ-40 2μl into the bilateral hippocampi by using a brain stereotaxic apparatus.The rats were randomly divided into 3 groups (n =6 each) using a random number table:normal sahne group (group NS),POCD group,and HBO treatment group(groupHBO).0.9％ normal saline 2 μl was injected into hippocampus in group NS.In group POCD,Aβ0 2 μl was injected into hippocampus.In group HBO,Aβ 2μl was injected into hippocampus,and then the rats received hyperbaric oxygen treatment lasting for 60 min once a day within 1-5 days after operation.Morris water maze test was performed on 7,14 and 21 days after operation in each group and the swimming distance and speed and escape latency were recorded.The animals were sacrificed after the end of test,the hippocampi were then removed to detect the activation of astrocytes (by immuno-histochemistry) and content of tumor necrosis factor-α (TNF-α) (by ELISA).Resets There were no significant differences in the parameters of behavior in Morris water maze test on 7 and 14 days after operation between the three groups.Compared with group NS,the swimming distance and escape latency were significantly prolonged,and the activation of astrocytes and TNF-α content were increased on 21 days after operation in group POCD,and the swimming distance and escape latency were significantly prolonged,the activation of astrocytes was increased,and no significant change was found in TNF-α content on 21 days after operation in group HBO.Compared with group POCD,the swimming distance and escape latency were significantly shortened,and the activation of astrocytes and TNF-α content were decreased in group HBO.There was no significant difference in the swimming speed at each time point among the three groups.Conclusion HBO treatment can alleviate POCD in rats,and the mechanism is related to inhibition of activation of astrocytes and inflammatory responses in hippocampi by HBO.

Objective To investigate the role of nuclear factor-kappa B (NF-κB)signaling pathway in propofol-induced suppression of up-regulation of inducible nitric oxide synthase (iNOS) gene expression in LPSstimulated RAW264.7 cells.Methods RAW264.7 cells were purchased from cell bank of Chinese Academy of Sciences and cultured in DMEM culture medium containing 10％ fetal bovine serum.The cells were seeded in 6 cm diameter dishes (3 ml/dish) or in 6-well plates (2 ml/well) with a density of 5 × 105/ml and randomly divided into 3 groups ( n =18): normal control group (group C),group LPS (group L)and group LPS + propofol (group LP).The cells were incubated with LPS 1 μg/ml in groups L and LP.Propofol 50μmol/L was added to the culture medium at 2 h before LPS in group LP.Cells were harvested at 30 min after being stimulated with LPS.Phosphorylation of IκB kinase(p-IKK) and NF-κB activity were detected by Western blot.The expression of iNOS mRNA was determined after 6 h exposure of the cells to LPS.Results LPS significantly up-regulated the expression of p-IKK and iNOS mRNA and increased NF-κB activity in group L as compared with group C.Propofol pretreatment significantly attenuated the effects of LPS on p-IKK,iNOS mRNA expression and NF-κB activity.Conclusion NF-κB signaling pathway is involved in the propofol-induced suppression of up-regulation of iNOS mRNA expression in LPS-stimulated RAW264.7 cells.

Objective To evaluate the relationship between extracellular signal-regulated kinase (ERK)and ketamine-induced apoptosis in rat hippocampal neurons.Methods Sprague-Dawley rats at 18 days of gestation were anesthetized.The fetal rats were obtained under the sterile condition and decapitated.The hippocampal neurons were isolated and primarily cultured for 5 days,and were seeded in 6-well plates (2 ml/well) or in 96-well plates (100μl/well) at a density of 5 × 105/ml.The cells were randomly divided into 4 groups (n =18 each):control group (group C),fibroblast growth factor (FGF-2,an ERK agonist) group (group F),ketamine group (group K) and FGF-2 + ketamine group (group FK).The cells were cultured in the plain culture medium in group C.FGF-2 50 ng/ml was added to the culture medium in group F.Ketamine was added to the culture medium in group K.FGF-2 50 ng/ml was added to the culture medium at 20 min before ketamine 100 μmol/L was added in group FK.The phosphorylation of ERK in hippocampal neurons was detected by Western blot at 10 min after treatment.At 24 h after treatment,the neuronal apoptosis was detected by Hoechst33342/PI staining,and the cell survival rate was detected by MTT assay.The apoptosis rate was calculated.Results Compared with group C,the phosphorylation of ERK in hippocampal neurons and the cell survival rate was significantly decreased and the apoptosis rate was increased in K and FK groups (P ＜ 0.05).There was no significant difference in the parameters mentioned above between F and C groups (P ＞ 0.05).The phosphorylation of ERK in hippocampal neurons and the cell survival rat was significantly higher and the apoptosis rate was lower in group FK than in group K (P ＜0.05).Conclusion Ketamine induces apoptosis in rat hippocampal neurons by inhibiting activation of ERK in hippocampal neurons.

Objective To investigate the relationship between the plasticity of dendritic spines in entorhinal cortical neurons and mechanism of low-dose ketamine-induced reduction of cognitive dysfunction following sevoflurane anesthesia in aged rats.Methods Thirty-six pathogen-free healthy male SpragueDawley rats,aged 18 months,weighing 500-600 g,were divided into 3 groups (n=12 each) using a random number table:control group (group C),sevoflurane anesthesia group (group Sev) and ketamine group (group K).Group C received no treatment.Group Sev inhaled the mixture of air (flow rate 1 L/min) and 3.6％ sevoflurane for 3 h.In group K,ketamine 10 mg/kg was injected intraperitoneally,and 5 min later the mixture of air (flow rate 1 L/min) and 3.6％ sevoflurane was inhaled for 3 h.Open field test and Morris water maze test were performed 3 days after anesthesia.After the behavioral tests,the animals were sacrificed,and their brains were removed and cut into sections for determination of the density of neurons,density of dendritic spines,and expression of postsynaptic density protein-95 (PSD-95) and synaptophysin (SY38) in superficial laminaes (Ⅱ-Ⅲ) of entorhinal cortex using Nissl's staining,Golgi staining and immunohistochemistry,respectively.Results Compared with group C,the time of staying at the central region was significantly shortened,the escape latency was prolonged,the density of dendritic spines was decreased,and the expression of PSD-95 and SY38 was down-regulated in group Sev (P＜0.05).Compared with group Sev,the time of staying at the central region was significantly prolonged,the escape latency was shortened,the density of dendritic spines was increased,and the expression of PSD-95 and SY38 was upregulated in group K (P＜0.05).There were no significant differences in the density of neurons in entorhinal cortex between the three groups (P＞0.05).Conclusion The mechanism by which low-dose ketamine attenuates cognitive dysfunction induced by sevoflurane anesthesia may be related to the enhanced plasticity of dendritic spines in entorhinal cortical neurons of aged rats.