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 effects of hyperbaric oxygen post-conditioning on the expression of P2X4 receptors in the spinal dorsal horn and hippocampus of rats with neuropathic pain (NP).Methods Seventytwo male Sprague-Dawley rats,aged 8-10 weeks,weighing 300-350 g,were randomly divided into 3 groups (n =24 each) using a random number table:sham operation group (group S),NP group and hyperbaric oxygen postconditioning group (group H).NP was induced by chronic constrictive injury.The rats in group H underwent hyperbaric oxygen treatment once a day for 7 consecutive days starting from 1 day after NP was successfully induced.After the rats were placed in the hyperbaric oxygen chamber,the pressure was increased at a rate of 10 kPa/min until the hyperbaric oxygen was at 2.0 atmosphere absolute,and maintained at this level for 60 min,and then the pressure was decreased at a rate of 10 kPa/min until the normal pressure was reached.The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured at 1 day before NP was induced and 1,3,7 and 14 days after NP was induced.After the end of measurement,6 rats were randomly chosen from each group and then sacrificed and the L4-6 segments of the spinal cord and hippocampal tissues were removed for determination of the expression of P2X4 receptors (by immunohistochemistry).Results Compared with group S,the MWT was significantly decreased,TWL was shortened,and P2X4 receptor expression in the spinal dorsal horn and hippocampus was up-regulated in NP and H groups.Compared with group NP,the MWT was significantly increased and TWL was prolonged,and P2X4 receptor expression in the spinal dorsal horn and hippocampus was down-regulated in group H.Conclusion Hyperbaric oxygen post-conditioning mitigates NP by down-regulating the expression of P2X4 receptors in the spinal dorsal horn and hippocampus of rats.

Objective To investigate the effect of intrathecal nerve growth factor (NGF) on lidocaineinduced neurotoxicity to the spinal cord in rats.Methods Thirty healthy male Sprague-Dawley rats,aged 8-10 weeks,weighing 250-300 g,were randomly divided into 5 groups (n =6 each) using a random number table:control group (group C),sham operation group (group S),lidocaine-induced neurotoxicity group (group L),normal saline group (group NS) and NGF group (group NGF).A catheter was inserted at L4.5 interspace into the epidural space in S,L,NS,and NGF groups.One day after surgery,20％ lidocaine 20 μl was injected intrathecally.At 24 h after lidocaine injection,normal saline 20 μl and NGF 10 μg (20 μd) were injected intrathecally in NS and NGF groups,respectively,once a day for 7 consecutive days.The tail flick latency (TFL) to a thermal nociceptive stimulus was measured on 1,3,5 and 7 days after lidocaine injection.The animals were sacrificed after the behavioral test was completed at 7 days after lidocaine injection,and the lumbar segments of the spinal cord were removed to detect the neuronal apoptosis (using flow cytometry) and caspase-3 mRNA expression (by RT-PCR).Results Compared with group C,the TFL was significantly prolonged at 1-7 days after lidocaine injection in L and NS groups and at 1-5 days after lidocaine injection in group NGF,the apoptosis rate was increased in L,NS and NGF groups,and caspase-3 mRNA expression was up-regulated in L and NS groups,and no significant change was found in the parameters mentioned above in group S.Compared with group L,the TFL was significantly shortened at 5 and 7 days after lidocaine injection,the apoptosis rate was decreased,and caspase3 mRNA expression was down-regulated in NGF group,and no significant change was found in the parameters mentioned above in group NS.Conclusion Intrathecal NGF can reduce lidocaine-induced neurotoxicity to the spinal cord in rats and inhibition of caspase-3 mRNA expression is involved in the mechanism.

Objective To investigate the effect of different pressures of hyperbaric oxygen (HBO) treatment on neuropathic pain (NP) in rats.Methods Twenty-four healthy male Sprague-Dawley rats were randomly divided into 4 groups (n =6 each):sham operation group (group S),NP group,treatment with HBO at 2.0 atmosphere absolute group (group HBO2.0) and treatment with HBO at 2.5 atmosphere absolute group (group HBO2.5).The animals were anesthetized with intraperitoneal 5 ％ 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.After the rats were placed in the HBO chamber,the pressure was increased at a rate of 10 kPa/min until the desired pressure was reached,and then the pressure was maintained at this level for 60 min.The pressure was then decreased at a rate of 10 kPa/min until the normal pressure was reached.HBO treatment was performed once a day for 5 consecutive days starting from 1st day after operation in groups HBO2.0 and HBO2.5.While the rats were only placed in the HBO chamber and stayed for 100 min in groups S and NP.The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured at 0,1and 2 h after leaving the HBO chamber (T0.2).Results Compared with group S,MWT was significantly decreased and TWL was shortened in group NP (P ＜ 0.05).Compared with group NP,MWT was significantly increased and TWL prolonged at T1 during the treatment (P ＜ 0.05),while no significant change was found in MWT and TWL at T2 during the treatment in groups HBO2.0 and HBO2.5 (P ＞ 0.05).There was no significant difference in MWT and TWL at each time point during the treatment between groups HBO2.0 and HBO2.5 (P ＞ 0.05).Conclusion Treatment with different pressures of HBO can reduce NP in rats,but the change in pressure dose not affect the analgesic efficacy.

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 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 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 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 analyze and summarize the risk factors of failed internal fixation for intertrochanteric fracture.Methods From April 2008 to April 2011,267 patients with intertrochanteric fractures in 4 hospitals were treated with internal fixation.The relationship between the failure of internal failure and possible factors as age,gender,hypertension,diabetes,the abuse of alcohol and tobacco,use of glucocorticoid,the degree of osteoporosis and fractures type were studied.According to the surgical risk assessment table,the patients were divided into low-risk,mid-risk,and high-risk group.The rate of internal fixation failure was compared in the 3 groups.Results We found 42 cases which showed radiographic failures.The internal fixation failure directly related with advanced age,diabetes,severe osteoporosis,unstable type fracture,but not gender,hypertension,the abuse of alcohol and tobacco,use of glucocorticoid.Risk factors of internal fixation failure included diabetes,osteoporosis degree,and fracture stability.Failed intertrochanteric fracture fixation mainly occurred in the mid-risk and high-risk groups.Conclusion Severe osteoporosis,unstable fracture,diabetes are risk factors of failure of intertrochanteric fracture fixation.These factors will affect the quality of surgery.For the patient with intertrochanteric fractures in the low-risk groups,internal fixation should be the first choice for treatment.For the patients in the mid-risk and high-risk group,internal fixation should be applied cautiously.For the aged patients in high-risk groups,hip arthroplasty is a wise option.

Objective To observe the behavior and the changes of neurologic and his-topathologic structure of rats injected lidocaine-bupivacaine mixtures in different ratio.Methods Af-ter successful intrathecal catherization and positive lidocaine test,48 rats were randomly allocated into 6 groups with 8 rats in each group.Rats received intrathecally NS (group S),mixture of 2.5% lido-caine and 1.875% bupivacaine (group LB13),3.33%lidocaine and 1.67% bupivacaine (group LB12),5% lidocaine and 1.25% bupivacaine (group LB11),6.67% lidocaine and 0.83% bupiv-acaine (group LB21),or 7.5% lidocaine and 0.625% bupivacaine (group LB31).TFL and PWT on consecutive 4 days,recovery time of lower limbs and the pathologic changes in the spinal cord by method of microscopy and electron scope were observed by a blind investigator.Results TFL in group LB31was significantly longer(P <0.05)and hind legs motor function and recover time pro-longed obviously in group LB31;Edema vacuolar degeneration and interstitial edema in white matter of posterior horn of spinal cord were found in group LB31.The histopathologic score was obviously higher in group LB31 compared with other groups (P <0.05).On transmission electroscope,differ-ent levels of ultrastructural changes were found in all groups except in group S .Typical changes included interstitial edema ,loosening of the laminae of myelinated fibers , axon swelling and local degeneration with most serious injury in group LB31.Conclusion The spi-nal injury following intrathecal local anesthetics mixtures was more serious with higher concentration of lidocaine in the mixture.Lidocaine concentration lower than 5% mixed with 1.25% bupivacaine intrathecally induces no obvious spinal neurotoxicity.