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Objective:To evaluate the effect of c-CBL overexpression on activation of astrocytes in the spinal cord of rats with neuropathic pain and the relationship with Kindlin-1.Methods:Eighteen clean-grade healthy male Sprague-Dawley rats, aged 10-12 weeks, weighing 250-280 g, were divided into 3 groups ( n=6 each) using a random number table method: sham operation group (S group), neuropathic pain group (NP group) and c-CBL overexpression group (c-CBL group). The model of neuropathic pain was developed by chronic compression of the sciatic nerve in anesthetized rats.On 1 day before operation, c-CBL overexpression vector 10 μl was intrathecally injected in group c-CBL, while blank vehicle 10 μl was intrathecally injected in S and NP groups.The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured on 1 day before operation (T 0) and 1, 4 and 7 days after operation (T 1-3). The rats were sacrificed by decapitation after measurement of the pain threshold at T 3, and the spinal cord of L 4-6 was taken for determination of the expression of Kindlin-1, glial fibrillary acidic protein (GFAP), tumor necrosis factor-alpha (TNF-α), and interleukin-1beta (IL-1β) (by Western blot) and co-expression of Kindlin-1 with c-CBL (by co-immunoprecipitation). Results:Compared with group S, the MWT was significantly decreased and TWL was shortened at T 2, 3 in group NP and group c-CBL, the expression of Kindlin-1, GFAP, TNF-α and IL-1β was significantly up-regulated in group NP, and the expression of c-CBL was significantly up-regulated in group c-CBL ( P<0.05). Compared with group NP, the MWT was significantly increased and TWL was prolonged at T 2, 3, the expression of Kindlin-1, GFAP, TNF-α and IL-1β was down-regulated, and the expression of c-CBL was up-regulated in group c-CBL ( P<0.05). The results of co-immunoprecipitation showed that there was a protein interaction and co-expression relationship between Kindlin-1 and c-CBL in group NP, and the co-expression of Kindlin-1 with c-CBL was enhanced in group c-CBL when compared with group NP. Conclusions:The overexpression of c-CBL can inhibit activation of astrocytes by down-regulating the expression of Kindlin-1 in the spinal cord, thus reducing inflammatory responses and relieving neuropathic pain in rats.
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Objective:To investigate the relationship between spinal long chain noncoding RNA (lncRNA) and kindlin-1/Wnt3a signaling pathway in a rat model of neuropathic pain (NP).Methods:The experiment was performed in two parts.Experiment Ⅰ Sprague-Dawley rats of both sexes, aged 7 days, weighing 15-20 g, were selected.Rats were sacrificed, the dorsal horn of spinal cord was removed, and the primary astrocytes were extracted and cultured.Lipopolysaccharide 1 μg/ml was added to induce the activation of astrocytes for 24 h. The lncRNA binding to kindlin-1 was identified using PCR immunoprecipitation method.The localization of lncRNA FOXF1-AS1 in astrocytes was observed by fluorescence in situ hybridization, and the binding between lncRNA FOXF1-AS1 and kindlin-1 was detected by biotin-labeled magnetic bead method.Experiment Ⅱ Thirty clean-grade healthy male Sprague-Dawley rats, aged 10-12 weeks, weighing 250-280 g, were divided into 5 groups ( n=6 each) using a random number table method: sham operation control group (group C), NP group, lncRNA FOXF1-AS1 overexpression group (group F), lncRNA FOXF1-AS1 overexpression plus kindlin-1 shRNA group (group FK) and lncRNA FOXF1-AS1 overexpression + Wnt inhibitor group (group FW). NP was induced by chronic constrictive injury in anesthetized animals.In group F, lncRNA FOXF1-AS1 overexpression lentivirus 10 μl was intrathecally injected at 28 days before operation, and vector virus 10 μl was intrathecally injected in the other groups.In FK group, kindlin-1 interfering shRNA interference adenovirus 10 μl, and vector virus 10 μl was intrathecally injected in the other groups.In group FW, Wnt inhibitor IWP-2 10 μl was intrathecally injected at 1-3 days after operation, artificial cerebrospinal fluid 10 μl was intrathecally injected at the same time point in the other groups.Mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) were measured at 1 day before operation, at 4 days and 7 days after operation.The animals were sacrificed at the end of measurement of pain threshold at 7 days after operation, and the spinal cord tissues were taken for determination of the expression of kindlin-1, Wnt3a and glial fibrillary acidic protein (GFAP) (by Western blot) and the contents of tumor necrosis factor (TNF)-α and interleukin (IL)-1β (IL-1β) (using enzyme-linked immunosorbent assay). Results:ExperimentⅠ lncRNA FOXF1-AS1, which was expressed in the cytoplasm of astrocytes, combined with kindlin-1.Experiment Ⅱ Compared with C group, MWT was significantly decreased, TWL was shortened at 4 and 7 days after operation, the expression of kindlin-1, Wnt3a and GFAP in spinal cord was up-regulated, and the contents of TNF-α and IL-1β were increased in group NP ( P<0.05). Compared with NP group, MWT was significantly decreased, TWL was shortened at 4 and 7 days after operation, the expression of kindlin-1, Wnt3a and GFAP in spinal cord was up-regulated, and the contents of TNF-α and IL-1β were increased in F group, MWT was increased, TWL was prolonged at 4 and 7 days after operation, and the contents of TNF-α and IL-1β were decreased in group FK and group FW, the expression of kindlin-1, Wnt3a and GFAP was down-regulated in group FK, and the expression of kindlin-1 was up-regulated, and expression of Wnt3a and GFAP was down-regulated in group FW ( P<0.05). Compared with group F, MWT was significantly increased, TWL was prolonged at 4 and 7 days after operation, and the contents of TNF-α and IL-1β were decreased in group FK and group FW, the expression of spinal kindlin-1, Wnt3a and GFAP was down-regulated in group FK, and expression of Wnt3a and GFAP was down-regulated in group FW ( P<0.05). Conclusion:lncRNA FOXF1-AS1 can up-regulate kindlin-1 expression, activate Wnt3a signaling pathway, promote astrocyte activation, and then regulate inflammatory responses and is involved in the process of neuropathic pain in rats.
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Objective:To evaluate the relationship between spinal kindlin-1/Wnt3a signaling pathway and inflammatory response in a rat model of neuropathic pain (NP).Methods:Twenty-four clean-grade healthy male Sprague-Dawley rats, aged 10-12 weeks, weighing 250-280 g, were divided into 4 groups ( n=6 each) using a random number table method: sham operation group (SH group), NP group, kindlin-1 shRNA group (K group) and Wnt3a inhibition group (W group). NP was induced by chronic constrictive injury in anesthetized animals.At 21 days before operation, kindlin-1 shRNA adenovirus vector 10 μl was intrathecally injected in group K, and empty viral vector 10 μl was intrathecally injected in SH, NP and W groups.Wnt inhibitor IWP-2 10 μl was intrathecally injected in group W, and artificial cerebrospinal fluid 10 μl was intrathecally injected in SH, NP and K groups at 1-3 days after operation.The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured at 1 day before operation and 4 and 7 days after operation, respectively.At the end of pain threshold measurement at 7 days after operation, the animals were sacrificed and the lumbar segments (L 4-6) of the spinal cord were obtained for determination of the contents of tumor necrosis factor (TNF)-α and interleukin (IL)-1β (IL-1β) (using enzyme-linked immunosorbent assay) and the expression of kindlin-1 and Wnt3a (by Western blot). Results:Compared with group SH, MWT was significantly decreased, TWL was shortened at 4 and 7 days after operation, and the contents of TNF-α and IL-1β in spinal cord were increased in NP, K, and W groups, the expression of kindlin-1 and Wnt3a was up-regulated in NP and W groups, and expression of Wnt3a was up-regulated in group K ( P<0.05). Compared with group NP, MWT was significantly increased and TWL was prolonged at 4 and 7 days after operation in K and W groups, the contents of TNF-α and IL-1β in spinal cord were decreased, and the expression of kindlin-1 and Wnt3a was down-regulated in group K, the contents of TNF-α and IL-1β in spinal cord were decreased, and the expression of Wnt3a was down-regulated in group W ( P<0.05), and no significant change was found in kindlin-1 expression ( P>0.05). Conclusion:Spinal kindlin-1 regulates the inflammatory response by up-regulating the expression of Wnt3a, and it is involved in the maintenance of NP in rats.
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Neutrophil extracellular traps (NETs) play an important role in the formation of immunothrombosis. However, how vascular endothelial cells mediate the formation of NETs has not been fully understood. We stimulated neutrophils firmly attached on the endothelial cell surface intercellular adhesion molecule-1 (ICAM-1) with lipopolysaccharide (LPS) or phorbol-12-myristate-13-acetate (PMA) for 4 h, then labeled NETs-DNA with Sytox green dye and the formation of NETs was observed by fluorescent microscopy. The area and fluorescence intensity of NETs-DNA were analyzed to quantify the formation of NETs. The results showed that both PMA and LPS were able to induce firmly adhered neutrophils on ICAM-1 to produce NETs. NETs induced by PMA were independent of neither β2 integrin lymphocyte function-associated antigen-1 (LFA-1) nor macrophage antigen complex-1 (Mac-1). In contrast, LPS-stimulated NETs were mediated by Mac-1 integrin, but not by LFA-1. After inhibition of actin filaments or Talin-1, the formation of NETs irrespective of the stimulus was significantly reduced. This study reveals the mechanism of the direct interaction between neutrophils and endothelial cells to produce NETs under inflammatory conditions, providing a new theoretical basis for the treatment of related diseases and the development of new drugs.
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Cytoskeletal Proteins , Endothelial Cells , Extracellular Traps , Integrins , Intercellular Adhesion Molecule-1 , Lipopolysaccharides/pharmacology , Macrophages , NeutrophilsABSTRACT
Objective To evaluate the role of spinal kindlin-1 in neuropathic pain in rats and the relationship with Wnt3a.Methods Eighteen clean-grade healthy male Sprague-Dawley rats,weighing 250-280 g,aged 10-12 weeks,were divided into 3 groups (n =6 each) using a random number table:sham operation group (group S),neuropathic pain group (group NP) and kindlin-1 inhibitor group (group K).Neuropathic pain was induced by chronic compression of the sciatic nerve.The sciatic nerve was only exposed but not ligated in group S.In group K,shRNA was intrathecally injected at 21 days before operation to inhibit the expression of kindlin-1.Vector virus was intrathecally injected at 21 days before operation in S and NP groups.The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured at 1 day before operation and 1,4,7,10 and 13 days after operation.Rats were sacrificed at 13 days after measurement of pain threshold and the spinal cord was removed for determination of the expression of kindlin-1 and Wnt3a (by Western blot) and expression of Wnt3a mRNA (by real-time polymerase chain reaction).Results Compared with group S,the MWT was significantly decreased and the TWL was shortened at 4,7,10 and 13 days,and the expression of Wnt3a protein and mRNA and kindlin-1 was up-regulated in group NP (P＜0.05).Compared with group NP,the MWT was significantly increased and the TWL was prolonged at 4,7,10 and 13 days,and the expression of Wnt3a protein and mRNA and kindlin-1 was down-regulated in group K (P＜0.05).Conclusion Kindlin-1 is involved in the development of neuropathic pain by up-regulating the expression of Wnt3a in rats.
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PURPOSE: To investigate the effects of hyperbaric oxygen (HBO) pretreatment on cognitive decline and neuronal damage in an Alzheimer’s disease (AD) rat model. MATERIALS AND METHODS: Rats were divided into three groups: normal saline (NS), AD, and HBO+AD. In the AD group, amyloid β peptide (Aβ)₁₋₄₀ was injected into the hippocampal CA1 region of the brain. NS rats received NS injection. In the HBO+AD group, rats received 5 days of daily HBO therapy following Aβ₁₋₄₀ injection. Learning and memory capabilities were examined using the Morris water maze task. Neuronal damage and astrocyte activation were evaluated by hematoxylin-eosin staining and immunohistochemistry, respectively. Dendritic spine density was determined by Golgi-Cox staining. Tumor necrosis factor-α, interleukin-1β, and interleukin-10 production was assessed by enzyme-linked immunosorbent assay. Neuron apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling. Protein expression was examined by western blotting. RESULTS: Learning and memory dysfunction was ameliorated in the HBO+AD group, as shown by significantly lower swimming distances and escape latency, compared to the AD group. Lower rates of neuronal damage, astrocyte activation, dendritic spine loss, and hippocampal neuron apoptosis were seen in the HBO+AD than in the AD group. A lower rate of hippocampal p38 mitogen-activated protein kinase (MAPK) phosphorylation was observed in the HBO+AD than in the AD group. CONCLUSION: HBO pretreatment improves cognition and reduces hippocampal damage via p38 MAPK in AD rats.
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Animals , Male , Rats , Alzheimer Disease/therapy , Amyloid beta-Peptides/administration & dosage , Apoptosis , Cognition/drug effects , Disease Models, Animal , Enzyme-Linked Immunosorbent Assay , Hippocampus/enzymology , Hyperbaric Oxygenation , In Situ Nick-End Labeling , Interleukin-10/biosynthesis , Interleukin-1beta/biosynthesis , Learning/drug effects , Memory/drug effects , Neurons , Peptide Fragments/administration & dosage , Rats, Sprague-Dawley , Sodium Chloride/administration & dosage , Tumor Necrosis Factor-alpha/biosynthesis , p38 Mitogen-Activated Protein Kinases/metabolismABSTRACT
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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.