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Objective To evaluate the relationship between p38 mitogen-activated protein kinase (p38MAPK) and G protein-coupled receptor kinase 2 (GRK2) in the development of persistent postoperative pain in rats.Methods Pathogen-free healthy male Sprague-Dawley rats,weighing 200-250 g,aged 2 months,were used in this study.Sixty rats in which intrathecal catheters were successfully implanted were divided into 6 groups (n =10 each) using a random number table method:sham operation group (group S),sham operation plus dimethyl sulfoxide (DMSO) group (group D),sham operation plus GRK2 degradation inhibitor MDL28170 group (group M),persistent postoperative pain group (group PPP),persistent postoperative pain plus DMSO group (group PPP+D) and persistent postoperative pain plus MDL28170 group (group PPP+M).Persistent postoperative pain was evoked by skin/muscle incision and retraction (SMIR).Immediately after operation and at 1,2 and 3 days after operation,normal saline 20 μl was intrathecally injected once a day in S and PPP groups,5％ DMSO 10 μl was intrathecally injected once a day in D and PPP+D groups,and MDL28170 10 μl (50 μg) was intrathecally injected once a day in M and PPP+M groups.The mechanical paw withdrawal threshold (MWT) was measured at 1 day before operation and 3,7,14 and 21 days after operation (T1-4).Four rats in each group were selected after behavioral testing at T3 and sacrificed,and the L4-6 segments of the spinal cord were removed for determination of the expression of phosphorylated p38MAPK (p-p38MAPK) by Western blot.Results There was no significant difference in MWT at each time point or expression of p-p38MAPK among group S,group D and group M (P＞0.05).Compared with group S,the MWT was significantly decreased,and the expression of p-p38MAPK was up-regulated in PPP,PPP+D and PPP +M groups (P＜ 0.05).Compared with group PPP,the MWT was significantly increased,and the expression of p-p38MAPK was down-regulated in group PPP+M (P＜0.05),and no significant change was found in the MWT or expression of p-p38MAPK in group PPP+D (P＞0.05).Conclusion Down-regulated expression of spinal GRK2 can promote the activation of p38MAPK in the spinal cord and is involved in the development of persistent postoperative pain in rats.
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Objective@#To evaluate the relationship between p38 mitogen-activated protein kinase (p38MAPK) and G protein-coupled receptor kinase 2 (GRK2) in the development of persistent postoperative pain in rats.@*Methods@#Pathogen-free healthy male Sprague-Dawley rats, weighing 200-250 g, aged 2 months, were used in this study.Sixty rats in which intrathecal catheters were successfully implanted were divided into 6 groups (n=10 each) using a random number table method: sham operation group (group S), sham operation plus dimethyl sulfoxide (DMSO) group (group D), sham operation plus GRK2 degradation inhibitor MDL28170 group (group M), persistent postoperative pain group (group PPP), persistent postoperative pain plus DMSO group (group PPP+ D) and persistent postoperative pain plus MDL28170 group (group PPP+ M). Persistent postoperative pain was evoked by skin/muscle incision and retraction (SMIR). Immediately after operation and at 1, 2 and 3 days after operation, normal saline 20 μl was intrathecally injected once a day in S and PPP groups, 5% DMSO 10 μl was intrathecally injected once a day in D and PPP+ D groups, and MDL28170 10 μl (50 μg) was intrathecally injected once a day in M and PPP+ M groups.The mechanical paw withdrawal threshold (MWT) was measured at 1 day before operation and 3, 7, 14 and 21 days after operation (T1-4). Four rats in each group were selected after behavioral testing at T3 and sacrificed, and the L4-6 segments of the spinal cord were removed for determination of the expression of phosphorylated p38MAPK (p-p38MAPK) by Western blot.@*Results@#There was no significant difference in MWT at each time point or expression of p-p38MAPK among group S, group D and group M (P>0.05). Compared with group S, the MWT was significantly decreased, and the expression of p-p38MAPK was up-regulated in PPP, PPP+ D and PPP+ M groups (P<0.05). Compared with group PPP, the MWT was significantly increased, and the expression of p-p38MAPK was down-regulated in group PPP+ M (P<0.05), and no significant change was found in the MWT or expression of p-p38MAPK in group PPP+ D (P>0.05).@*Conclusion@#Down-regulated expression of spinal GRK2 can promote the activation of p38MAPK in the spinal cord and is involved in the development of persistent postoperative pain in rats.
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Objective To investigate the effects of inverse ratio ventilation on pulmonary function and ce-rebral oxygen saturation in elderly patients with single lung ventilation.Methods Sixty patients scheduled for elec-tive radical resection of esophageal cancer were divided into 2 groups(n=30 for each group)using a random num-ber table:the experiment group(group A)and the control group(group B). During the two lung ventilation,the ventilator parameters were set as tidal volume(VT)7 mL/kg,inspiratory to expiratory ratio 1:2. During one lung ventilation,the I:E ratio was 1.5:1 in the group A and 1:2 in the group B. At 15 min after two lung ventilation (T1),20 min after one lung ventilation(T2),60 min after one lung ventilation(T3)and 15 min after restarting two-lung ventilation(T4),the blood gas analysis was measured and recorded for the hemodynamics,respiratory me-chanics index and cerebral oxygen saturation respectively. Results Compared with the B group,the Ppeak and VD/VT at T2~T4in the group A were lower while PaO2,Pmean and Cdyn were higher(P<0.05).During one lung ventilation,the incidence of rSO2< 50% or rSO2decreased more than 20% in the group A was lower than that in the group B(P<0.05).The PaO2,Cdyn and rSO2of the two groups at T2~T4were significantly lower and Ppeak, Pmean,PaCO2,VD/VT were significantly higher than the baseline(T1)(P < 0.05). Conclusion During one-lung ventilation,prolonged inspiratory time can improve pulmonary function and lung compliance without increas-ing peak airway pressure,reduce the decline of rSO2 at the same time.
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Objective To evaluate the role of sonic hedgehog (SHH) signaling pathway in spinal neurons in morphine tolerance (MT) in mice.Methods Pathogen-free healthy female Kunming mice,weighing 20-25 g,aged 8-10 weeks,were used in the study.MT was induced with morphine 10 mg/kg injected subcutaneously twice a day for 7 consecutive days.The experiment was performed in two parts.Experiment Ⅰ Forty-eight mice were randomly assigned into 2 groups:control group (group C,n =8) and MT group (group M,n=40).The thermal pain threshold (TPT) was measured at 1 day before morphine injection and 1,3,5,7 and 14 days after the end of injection.Eight mice in each group were sacrificed at 2 h after measurement of TPT at each time point after the end of injection in group M or at 2 h after the last measurement of TPT in group C,and the lumbar segment (L4-6) of the spinal cord was removed.Experiment Ⅱ Forty-eight mice were randomly assigned into 6 groups (n=8 each):SHH inhibitor cyclopamine plus MT group (group CP+M),cyclopamine solvent plus MT group (group D1 +M),SHH agonist SAG plus MT group (group SAG+M),SAG solvent plus MT group (group D2+M),MT plus cyclopamine group (group M+CP) and morphine plus cyelopamine solvent group (group M+D1).At 15 min before morphine injection,cyclopamine 10 mg/kg was injected subcutaneously in group CP+M,and SAG 5 mg/kg was injected subcutaneously in group SAG+M.Cyclopamine 10 mg/kg was injected subcutaneously once a day during the 1-3 days after the end of morphine injection in group M+CP.The TPT was measured before injection of morphine,at 30 min after the first injection of morphine every day and at 1-3 days after the end of morphine injection.The animals were sacrificed at 2 h after the last measurement of TPT,and the lumbar segment (L4-6) of the spinal cord was removed for determination of the expression of SHH signaling pathway-related proteins SHH,ptch1,smo,gli1 and gli3 using Western blot.Results Experiment Ⅰ Compared with group C,the TPT was significantly decreased at 1 and 3 days after the end of morphine injection (P＜0.05),no significant change was found in TPT at 5-14 days after the end of morphine injection (P＞0.05),and the expression of SHH,smo and glil at 1-5 days after the end of morphine injection,of ptchl at 1 and 3 days after the end of morphine injection and of gli3 at 7 days after the end of morphine injection was up-regulated in group M (P＜0.05).Experiment Ⅱ Compared with group D1+M,the TPT was significantly increased,the expression of SHH,ptchl,smo and glil was down-regulated,and gli3 expression was up-regulated in group C P+M (P＜0.05).Compared with group D2+M,the TPT was significantly decreased,the expression of SHH,ptch1,smo and glil was up-regulated,and gli3 expression was down-regulated in group SAG+M (P＜0.05).There was no significant difference in the parameters mentioned above between group M+CP and group M+D1 (P＞0.05).The TPT was significantly lower on 3rd-7th days after beginning of morphine injection and 1-3 days after the end of morphine injection than at 30 min after the first injection of morphine in group CP+M (P＜0.05).Conclusion The mechanism underlying the development of MT is partially related to activation of SHH signaling pathway in spinal neurons of mice,however,the maintenance mechanism has no marked relationship with it.
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Objective To investigate effects of preoperative application of parecoxib on postoperative analgesia and coagulation function in neurosurgical patients.Methods A total of 90 patients (38 males and 52 females,ASA physical status Ⅰ or Ⅱ) undergoing crainotomy were randomly divided into two groups(n=45): parecoxib group (group P) and control group (group C).At 30 min before operation,group P received intravenous injection of parecoxib 40 mg (5 ml),group C intravenous injection of saline 5 ml.Postoperative patient-controlled intravenous analgesia (PCIA) was performed in all patients.PCIA formula of sufentanil 2 μg/kg+tropisetron 0.2 mg/kg,were diluted with normal saline to 120 ml.The visual analogue scale (VAS),the total and effective PCIA pump compressions,Ramsay sedation scale of 2,4,16,24,48 h after operation were recorded.Coagulation function was measured before and 2 h,48 h after parecoxib administration.Meanwhile,adverse reactions were recorded.Results Comparion of VAS between the two groups was made within 48 h after surgery,the total and effective PCIA pump compressions,were much more in group C than in group P (P<0.05).Ramsay sedation scale of group C was higher than that in group P at 2 h after operation.There were no significant differences in coagulation function.And the percentage of patients′ adverse effects in group P was lower than that in group C (P<0.05).Conclusion Parecoxib,as an analgesic,can enhance analgesic effect of sufentanil PCIA.Not only does it reduce the amount of sufentanil and incidence of adverse reactions,but also it has no significant effect on blood coagulation function.
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Objective To explore the effect of high-dose methylprednisolone combined with femoral nerve block on postoperative analgesia and recovery following total knee arthroplasty(TKA).Methods We performed a randomized,placebo-controlled,double-blind study. 60 patients were divided into a study group(groupMF)and a control group(F group).Patients in group MF received high-dose methylprednisolone combined with femoral nerve block. Patients in group F received equivalent saline combined with femoral nerve block. The rest pain and activi-ties pain,uses of analgesic medication,24 h CRP,time to ambulation,and adverse reactions after operation were recorded.Results There were significant differences in the rest pain and activities pain at hours 6,12,24,and 48,uses of analgesic medication,24 h CRP,time to ambulation and PONV(P < 0.05),group MF was better than group F.There was no significant difference in other adverse reactions(P>0.05).Conclusions High-dose methylprednisolone combined with femoral nerve block can effectively relieve pain and reduce uses of analgesic drugs after TKA,with less systemic inflammatory response and PONV.It is helpful for the early recovery in knee function.
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Objective To evaluate the effects of intrathecal low-dose naloxone,morphine and fentanyl on the expression of motillin (MTL) in the hippocampus of rats with incisional pain.Methods Seventy-two healthy male Sprague-Dawley rats,weighing 180-220 g,aged 6-8 weeks,in which intrathecal catheters were successfully implanted,were randomly divided into 6 groups (n =12 each) using a random number table:normal saline group (NS group),incisional pain group (P group),morphine + fentanyl + incisional pain group (MFP group),and naloxone (0.2,1.0 and 5.0 ng/kg) + morphine + fentanyl groups (MFPN1,MFPN2 and MFPN3 groups).Incisional pain was induced by an incision made into the plantar surface of the right hindpaw.At 20 min before induction of incisional pain,the mixture of morphine 5 μg/kg and fentanyl 0.25 mg/kg was injected intrathecally in group MFP,and the mixture of naloxone 0.2,1.0 and 5.0 ng/kg,morphine and fentanyl were injected intrathecally in MFPN1,MFPN2 and MF-PN3 groups,respectively.Six rats in each group were selected,and the mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured at 24 h before intrathecal catheterization (T0,baseline),at 24 h before induction of incisional pain (T1),and at 1,3 and 6 h after operation (T2-4).The left 6 rats in each group were selected and sacrificed at 6 h after operation,and the hippocampi,body of the stomach and duodenum were removed for detection of MTL content by enzyme-linked immunosorbent assay.Results Compared with group NS,the MWT was significantly decreased,and the TWL was shortened at T2-4 in P and MFPN3 groups,the MWT was significantly decreased,and the TWL was shortened at T4 in group MFPN1,and the TWL was prolonged at T2 in group MFPN2,the MTL contents in hippocampus and body of the stomach were significantly decreased in P,MFP,MFPN1 and MF-PN3 groups,the MTL contents in duodenum were increased in P and MFPN3 groups,and the MTL contents in duodenum were decreased in MFP and MFPN1 groups (P＜0.05),and no significant change was found in the parameters mentioned above in group MFPN2 (P＞0.05).Conclusion Intrathecal naloxone 1.0 ng/kg combined with morphine and fentanyl can inhibit up-regulation of the expression of MTL in the hippocampus of rats with incisional pain,and then is involved in the maintenance of stable gastrointestinal motility.
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Objective To establish a scald-induced pain model using a constant-temperature electrical scald instrument in rats.Methods Thirty-six pathogen-free male Sprague-Dawley rats, weighing 200-250 g, were randomly divided into 4 groups (n =9 each) using a random number table: control group (group C), scald for 5 s group (group S5), scald for 10 s group (group S10), and scald for 15 s group (group S15).The rats were anesthetized with intraperitoneal chloral hydrate.In S5, S10 and S15 groups, the plantar surface of the left hindpaw of rats were exposed to a constant-temperature electrical scald instrument (85 ℃) for 5, 10 and 15 s, respectively.The plantar surface of the left hindpaw of rats was exposed to an electrical scald instrument (room temperature) for 10 s in group C.At 1 day before treatment (T0),and 1, 3, 5, 7 and 14 days after treatment (T1-5), the mechanical and thermal pain thresholds were measured.Immediately after treatment, and at 24 h after treatment, the total body condition, wound color, and shape of the margin of the wound were observed and recorded.At 24 h after treatment, 3 rats were randomly sacrificed, and the skin from the plantar surface of the left hindpaw was removed for microscopic examination.Results Compared with group C, the thermal pain threshold at T1-2, and the mechanical pain threshold at T1-3 were significantly decreased in group S5, and the thermal pain threshold,and mechanical pain threshold were significantly decreased at T1-4 in group S10 (P＜0.05).The thermal pain threshold ＞ 25 s, and the mechanical pain threshold ＞30 g at T1-5 in group S15.The swelling in foot was bovious, burn blister appeared, and the degree of damage was aggravated in group S10 compared with S5 and S15 groups.Conclusion The scald-induced pain model is successfully established using a constant-temperature electrical scald instrument in rats.
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Objective To observe a new phosphodiesterase-4 inhibitor Ro 20-1724 on ketamine anesthesia-induced learning and memory impairment and cAMP/PKA-CREB-BDNF signal pathway in immature rats.Methods Twenty-four 21 day-old SD rats were randomly divided into 4 groups (n=6 each):control group (group C) ;ketamine group (group K) ;ketamine+Ro 20-1724 group(group K+Ro) and ketamine+vehicle (0.1％ ethanol) group (group K+E).Ketamine 70 mg/kg was injected intraperitoneally(IP) once a day for 7 consecutive days in groups K,K+Ro,and K+E.Ro 20-1724 0.5 mg/kg and equal volume of vehicle were injected IP at 30 min after IP ketamine each time respectively.Morris water maze was used to assess learning and memory ability after 2 days normal feeding,the escape latency and frequency of passing the platform were recorded.The animals were killed after water maze test and the cAMP,PKA,p-CREB,and BDNF protein expression in hippocampus were detected.Results Repetitive ketamine anesthesia significantly prolonged the escape latency (P＜0.01),decreased the frequency of passing the platform(P＜0.01),and down-regulated the expression of cAMP,PKA,p-CREB,and BDNF protein ((280±31) pmol/mg vs (210± 19) mol/mg,P＜0.01 ; 1.32±0.11 vs 1.13±0.12,P＜0.01 ; 2.61 ±0.22 vs 2.03 ± ±0.19,P＜0.01 ; 1.51 ±0.14 vs 1.16±0.10,P＜0.05) ; Compared with group K,Ro 20-172,significantly attenuated the escape latency time(P＜0.05,P＜0.01)and increased the frequency of passing the platform(P＜0.01),and ameliorated the expression of cAMP,PKA,p-CREB,and BDNF protein ((210± 19) pmoL/mg vs (240± 27) pmol/mg,P ＜0.05;1.13±0.12 vs 1.28±0.12,P＜0.05;2.03±0.19 vs 2.32±0.21,2.32±0.21;1.16±0.10 vs 1.37±0.11,P＜0.01).There was no difference between group K+Ro and group C,and between group K+E and group K(P＞0.05).Conclusion ketamine anesthesia-induced learning and memory impairment can be improved by Ro 20-1724,and cAMP/PKA-CREB-BDNF signal pathway in hippocampus participated in the changes.
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Objective To observe the effects of nAChR antagonistα-conotoxin Eb1.6 on ther-mal pain threshold and spinal IL-1βexpression levels and astrocytes activation in rats using L5 spinal nerve transaction (SNT)model.Methods Fifty male Sprague-Dawley rats were randomly assigned into 5 groups with each group 10 rats:sham group,different doses of α-CTX Eb1.6 (0.1 5,1.5 and 1 5 nmol/kg)groups and the saline group after SNT.Saline solution or different doses of Eb1.6 were intraperitoneally injected seven days after the surgery when the model was stable and the treatment continued for seven days.Measured the TWLs of all groups of the rats 1,2,4,7,12 hours after the in-jection on 7 d and 13 d.The rats were sacrificed and L5 spinal cord tissues were collected immediately after the behavioral tests on 13 d.The expression of GFAP and IL-1βwere assessed by Western blot assay and enzyme linked immunosorbent assay (ELISA)separately.Results Groups E1,E2,E3 and C had shorter TWL before the injection on 7 d and 13 d than group N(P <0.05).The TWLs of the rats in groups E1,E2 and E3 of 1 h,2 h and 4 h after the injection on 7 d were significantly higher than that before the injection(P <0.05)with 2 h after the injection showed the most obvious change.The TWL of 1 h,2 h,4 h and 7 h after the injection of the rats in group E1,E2 and E3 and those of 12 h after the injection of the rats in group E2 and E3 on 13 d were significantly higher than that before the injection(P <0.05 )and also higher than TWL of the respective time points on 7 d(P < 0.05 ),also with 2 h after the injection showed the most obvious change.The TWLs of 2 h after the injection a-mong group E1,E2 and E3 showed significant differences both on 7 d and 13 d (P <0.05).Rats spi-nal IL-1βand GFAP expression levels of group E1,E2,E3 and C were significantly higher than those of group N(P <0.05).Rats spinal IL-1β and GFAP expression levels of groups E1,E2,E3 signifi-cantly decreased compared with group C(P <0.05).There were significant differences among the spi-nal IL-1βand GFAP expression levels of group E1,E2 and E3(P <0.05).Conclusion Eb1.6 dose-de-pendently reduced the thermal hyperalgesia induced by L5 spinal nerve transection.Repeated treat-ment of Eb1.6 could produce better analgesic effect,which might be partly attribute to the inhibition of spinal IL-βlevels and astrocytes activation.
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Objective To valuate the effect of Ro20-1724 on ketamine-induced apoptosis in hippocampal neurons of neonatal rats.Methods Hippocampal neurons from newborn Sprague-Dawley rats were obtained and cultured in vitro.The primary hippocampal neurons were randomly divided into 4 groups (n =24 each) using a random number table:control group (group C),ketamine group (group K),solvent control group (group E),and Ro20-1724 group (R group).The neurons were incubated for 72 h in the normal culture medium in group C.The neurons were incubated for 72 h in the culture medium containing ketamine 150 μmol/L in group K.In E and R groups,after the neurons were incubated for 30 min in the culture medium containing ketamine 150 μmol/L,the culture medium was then replaced,0.01％ ethanol (final concentration) and 1 × 10-3 μmol/L Ro20-1724 (final concentration) were added to the culture medium,respectively,and the neurons were then incubated for 72 h.After 72 h incubation,the cell viability was detected by MTT assay,the cell apoptosis was detected by flow cytometry,the expression of Bcl-2 mRNA and Bax mRNA was determined by RT-PCR,and synaptophysin Ⅰ expression was detected by Western blot.The apoptosis rate was calculated.Results Compared with group C,the survival rate was significantly decreased,the apoptosis rate was increased,the expression of Bcl-2 mRNA and synaptophysin Ⅰ was down-regnlated,and Bax mRNA expression was up-regulated in K and E groups (P ＜ 0.05 or 0.01).Compared with group K,the survival rate was significantly increased,the apoptosis rate was decreased,the expression of Bcl-2 mRNA and synaptophysin Ⅰ was up-regulated,and Bax mRNA expression was downregulated in R group (P ＜ 0.05 or 0.01).Conclusion Ro20-1724 can inhibit ketamine-induced apoptosis in hippocampal neurons of neonatal rats and correction of Bcl-2/Bax imbalance is involved in the mechanism.
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Objective To investigate the effect of propofol on the activation of c-Jun N-terminal kinase (JNK) in hippocampus following asphyxial cardiac arrest-resuscitation in rats.Methods Forty male Sprague-Dawley rats,aged 6 months,weighing 350-380 g,were randomly divided into 4 groups (n =l0 each):sham operation group (group S),asphyxial cardiac arrest-cardiopulmonary resuscitation group (group CA-CPR),propofol group (group P) and normal saline group (group NS).All the rats were tracheostomized and mechanically ventilated after anesthetization.Cardiac arrest was induced by clamping the tracheal tube at the end of exhalation until ECG activity disappeared and MAP ＜ 10 mm Hg.Resuscitation was started 3 min later.MAP ＞ 60 mm Hg and HR ＞ 250 bpm were considered to be signs of successful resuscitation.Propofol 2 mg/kg was injected intravenously at 30 min before asphyxia,followed by propofol infusion at a rate of 4 mg· kg-1 · h-1 until the start of resuscitation in group P,while the equal volume of normal saline was given in group NS.At 12 h after successful resuscitation,the animals were sacrificed and brains were harvested for determination of wet/dry brain weight (W/D) ratio in brain tissues and expression of phosphor-JNK (p-JNK) in hippocampus (by immuno-histochemistry and Western blot),and for examination of the pathological changes of hippocampus.Results Compared with group S,W/D ratio was significantly increased and the expression of p-JNK in hippocampus was up-regulated in CA-CPR,P and NS groups (P ＜ 0.05 or 0.01).Compared with group CA-CPR,W/D ratio was significantly decreased and the expression of p-JNK in hippocampus was down-regnlated in group P (P ＜ 0.05 or 0.01),and no significant change was found in the indexes mentioned above in group NS (P ＞ 0.05).The pathological changes of hippocampus were significantly attenuated in group P compared with group CA-CPR.Conclusion Propofol can inhibit the activation of JNK in hippocampus following asphyxial cardiac arrest-resuscitation in rats and thus reducing brain injury.
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Objective To evaluate the changes in the activity of extracellular signal-regulated protein kinase 5 (ERK5) in the spinal cord in a rat model of bone cancer pain (BCP).Methods One hundred and eight female Sprague-Dawley rats,weighing 160-180 g,were randomly divided into 3 groups (n =36 each):control group (group C):sham operation (group S) and group BCP.In group BCP Walker 256 mammary gland cancer cell suspension (1 × 105 cells/ml) 5 μl was injected into the left tibia,while in group S normal saline 5μl was injected into the left tibia instead of cancer cell suspension.Group C underwent no treatment.Mechanical paw withdrawal threshold to von Frey filament stimulation (MWT) was measured at 1 day before inoculation and 3,5,7,14 and 21 days after inoculation.Six rats were sacrificed after the last measurement of MWT in groups C and S or after measurement of MWT at 3,5,7,14 and 21 days after inoculation in group BCP and the spinal cord was removed for determination of the expression of phosphorylated ERK5 (p-ERK5),ERK5 and Fos protein in the spinal dorsal horn by Western blot analysis.Results There was no significant difference in the MWT and expression of p-ERK5,ERK5 and Fos protein at each time point between groups C and S (P ＞ 0.05).Compared with groups C and S,MWT was significantly decreased at 7-21 days after inoculation,the expression of p-ERK5 and Fos protein was significantly up-regulated at 5-21 days after inoculation (P ＜ 0.05),and no significant change was found in the expression of ERK5 in group BCP (P ＞ 0.05).Conclusion Intra-tibial inoculation of Walker-256 breast cancer cells can increase the activity of ERK5 in the spinal cord in rats,leading to the increased release of Fos protein,thus inducing BCP.
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Objective To evaluate the effects of intrathecal low-dose naloxone,morphine and fentanyl on the expression of motilin (MTL) in the spinal cord in rats with incisional pain.Methods Seventy-two healthy male Sprague-Dawley rats,weighing 180-220 g,in which intrathecal catheters were successfully implanted,were randomly divided into 6 groups (n =12 each) using a random number table:normal saline group (NS group),morphine + fentanyl group (MF group),incisional pain group (P group),naloxone + incisional pain group (NP group),morphine + fentanyl + incisional pain group (MFP group),and morphine + fentanyl + naloxone +incisional pain group (MFNP group).Incisional pain was induced by an incision made into the plantar surface of the right hindpaw.At 20 min before induction of incisional pain,the mixture of morphine 5 μg/kg and fentanyl 0.25 μg/kg was injected intrathecally in MF,MFP and MFNP groups,and naloxone 1 ng/kg was given in NP and MFNP groups.Six rats from each group were randomly chosen,and paw withdrawal threshold to mechanical stimulation (PWMT) and paw withdrawal latency to thermal stimuli (PWTL) were measured before intrathecal catheterization (T0,baseline),at 24 h before induction of incisional pain (T1),and at 1,3 and 6 h after induction of incisional pain (T2-4).The left 6 rats from each group were chosen and sacrificed and the spinal cord were removed at 6 h after operation for detection of MTL content in the spinal cord,body of the stomach and duodeum tissues (by ELISA).Results Compared with the baseline value at T0,PWMT was significantly increased at T3,and PWTL was prolonged at T2-4 in MF group,PWMT was decreased and PWTL was shortened at T2-4 in P group and at T3,4 in NP group,PWMT was increased at T2,3 in MFP group,and PWMT was increased and PWTL was prolonged at T2 in MFNP group (P ＜ 0.05).Compared with NS group,MTL contents in spinal cord and body of the stomach were significantly decreased in MF and NP groups,MTL cortent in duodeum was decreased in group MF,while increased in group NP and MTL content in spinal cord was increased,and MTL content in body of the stomach was decreased in P and MFP groups,MTL content in duodeum was increased in group P,while decreased in group MFP(P ＜ 0.05),however,no significant change was found in MTL content in MFNP group (P ＞ 0.05).Conclusion Intrathecal low-dose naloxone combined with morphine and fentanyl can inhibit up-regulation of the expression of MTL in the spinal cord in rats with incisional pain and is involved in the maintenance of stable gastrointestinal motility.
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Objective To investigate the effect of RO20-1724 on the cognitive function in immature rats after ketamine anesthesia.Methods Ninety-six SD rats of both sexes,aged 21 days,weighing 45-55 kg,were randomly divided into 8 groups ( n =12 each):control group (group C) ; ketamine group (group K) ; ketamine + normal saline group (group K + N) ; ketamine + anhydrous alcohol group (group K + A) ; ketamine + 4 different doses of RO20-1724 groups (group K + R1-4 ).The rats were anesthetized with intraperitoneal injection of kctamine 70 mg/kg in groups K,K+N,K+A and K+.R1-4.Normal saline 2 ml,anhydrous alcohol (in normal saline 2 ml),and RO20-1724 0.25,0.50,0.75 and 1.00 mg/kg (in anhydrous alcohol 8 μl and then in normal saline 2 ml) were injected intraperitoneally in groups K + N,K + A and K + R1-4 respectively 30 min later.Six rats from each group were randomly selected at 24 h after administration and Morris water maze was used to test the ability of learning and memory.Six rats from each group were sacrificed at 48 h after administration and hippocampus and cerebral cortex were removed for determination of the expression of CREB and phospho-CREB (p-CREB) by Western blot.Ressults Compared with group C,the escape latency was significantly prolonged at 2-4 days after administration,the number of animals' swimming across the platform decreased,and the expression of CREB and pCREB in hippocampus and cerebral cortex down-regulated in groups K,K+ N,K+ E,K+ R1 and K+ R2(P ＜0.05 ).Compared with group K,the escape latency was significantly shortened at 2-4 days after administration,the number of animals' swimming across the platform increased,and the expression of CREB and p-CREB in hippocampus and cerebral cortex up-regulated in groups K + R3 and K + R4 ( P ＜ 0.05).Compared with groups K + R1 and K + R2,the escape latency was significantly shortened at 2-4 days after administration,the number of animals' swimming across the platform increased,and the expression of CREB and p-CREB in hippocampus and cerebral cortex up-regulated in groups K+ R3 and K+ P4(P ＜ 0.05).There were no significant differences in the escape latency,the number of animals' swimming across the platform,and the expression of CREB and p-CREB in hippocampus and cerebral cortex between groups K + R1 and K + R2,and between groups K + R3 and K + R4 ( P ＞ 0.05 ).Conclusion RO20-1724 0.75-1.00 mg/kg can improve ketamine-induced cognitive dysfunction by up-regulating CREB and p-CREB expression in hippocampus and cerebral cortex in immature rats.
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ObjectiveTo investigate the effect of dexamethasone on mitogen-activated protein kinase phosphatase-1 (MKP-1) expression in lung tissues in rats with lipopolysaccharide (LPS)-induced acute lung injury (ALI).MethodsFifty-four male SD rats weighing 180-230 g were randomly divided into 3 groups:control group (group C,n =6) ;ALI group ( n =24) and dexamethasone group (group D,n =24).LPS 5 mg/kg was injected via tail vein in groups ALI and D,while the equal volume of normal saline was given in group C.Dexamethasone 6 mg/kg was injected intraperitoneally at 30 min before LPS administration in group D.Eight rats in each group were sacrificed at 1 h after normal saline administration (T1) in group C and at 1,3,and 6 h after LPS administration (T1-3 ) in groups ALI and D.The lung tissues were then removed for determination of the expression of phosphorylated p38 mitogen-activated protein kinase (p-p38MAPK) and MKP-1.The concentrations of albumin and TNF-α in bronchoalveolar lavage fluid (BALF) were detected and histopathological changes were observed at T3 ·Another 32 SD rats weighing 180-230 g were randomly divided into 2 groups ( n =16 each):group ALI1 and group D1.The rats were treated as the method mentioned above and the 48 h survival condition was observed.Results Compared with group C, the concentrations of protein and TNF-α in BALF were significantly increased,p-p38MAKP expression was up-regulated at T1.3,and MKP-1 expression was down-regulated at T2,3 in group ALI,and TNF-α concentration in BALF was significantly increased and the expression of p-p38MAKP and MKP-1 was up-regulated at T1-3 in group D ( P ＜ 0.05).Compared with group ALI,the concentrations of protein and TNF-α in BALF were significantly decreased,p-p38MAKP expression was down-regulated and MKP-1 expression was up-reg-ulated at T1-3 ( P ＜ 0.05 ),and the pathological damage was attenuated in group D.The 48 h survival rate was significantly higher in group D1 than in group ALI1 ( P ＜ 0.05).ConclusionThe mechanism by which dexamethasone attenuates the ALI induced by LPS may be related to up-regulation of MKP-1,inhibition of phosphorylation of p38MAPK and decrease in inflammatory response.
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Objective To evaluate the role of JNK signal pathway in brain injury after resuscitation in a rat model of asphyxia cardiac arrest.Methods Forty healthy male SD rats 'weighing 300-350 g were randomly divided into 4 groups ( n =10 each):sham operation group (group SH) ; cardiac arrest group (group CA) ; group SP600125-JNK inhibitor (group SP) and dimethyl sulfexide (DMSO) group.The rats were anesthetized with intraperitoneal pentobarbital 45 mg/kg,tracheostomized and mechanically ventilated.PETCO2 was maintained at 35-45 mm Hg.Femoral artery and vein were cannulated for BP monitoring and fluid infusion.Cardiac arrest was induced by clamping tracheal tube until ECG activity disappeared and MAP ＜ 10 mm Hg.Resuscitation was started at 3 min after cardiac arrest.MAP ＞ 60 mm Hg and HR ＞ 250 bpm were considered to be signs of successful resuscitation.SP600125 20 mg/kg and DMSO 0.2 ml were injected iv as soon as chest compression was started in groups SP and DMSO respectively.The animals were sacrificed at 5 h after successful resuscitation and their brains were removed for determination of wet/dry (W/D) weight ratio and microscopic examination of hippocampus.Neuronal apoptosis was detected by TUNEL.Results Cardiac arrest significantly increased W/D ratio and the number of apoptotic cells in group CA.SP600125 iv significantly attenuated the cardiac arrest-induced increase in W/D ratio and the number of apoptotic cells but DMSO did not.Conclusion JNK signal pathway is involved in the brain injury after resuscitation in a rat model of asphyxia cardiac arrest.
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ObjectiveTo explore the effects and underlying mechanisms of acid sensing ion channels (ASICs) on pain behavior in a rat model of post-incision pain.MethodsFifty-eight adult male Sprague Dawley rats were used in this study,four rats were used for immunofluorescence test,thirty rats were employed for pain behavior test,and twenty-four rats were used for Western blot.Rats used for pain behavior test and Western blot were randomly divided into 3 groups:control group ( C group),incision pain model group ( I group) and amiloride group (A group).Plantar skin of rats in A group were infiltrated with 20 μl(200 μg)amiloride solution.Paw withdrawal mechanical threshold(PWMT) and paw withdrawal thermal latency(PWTL) of all rats in pain behavior test was tested at 24 h preoperative,2 h,4 h,8 h,12 h,24 h postoperative.Western blot was tested at 4 h postoperative.ResultsImmunofluorescence test displayed ASIC3 was expressed in plantar skin of all rats.The basal level of PWMT and PWTL of all rats in three groups was C group( (23.15 ± 5.10) g,( 11.32 ± 1.21 ) s),I group ( (23.26 ± 5.69) g,( 11.75 ± 2.01 ) s),A group ( (23.63 ± 4.96 ) g,( 11.47 ± 1.96) s) respectively,which was no significantly difference (P ＞ 0.05 ).PWMT and PWTL of I group and A group was significantly lower than that of C group at all time points postoperative (P ＜ 0.05) ; PWMT and PWTL of A group was at 2 h( ( 13.75 ±3.25)g,(9.96±1.32)s),4h((14.05±3.75)g,(9.17±2.11)s),8 h((9.75 ±2.74)g,(8.11 ±1.22)s)postoperative,which was significantly higher than that of I group (P ＜ 0.05 ).Compared with that of C group,the level of pERK1/2 expression was significantly increased in I group at 4 h postoperative (P ＜ 0.05 ),which could be inhibited by amiloride local infiltration (P ＜ 0.05 ).ConclusionASIC3 can mediate incision pain in a rat model of post-incision pain,through pERK1/2 signaling pathway,which can be inhibited by amiloride.
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Objective To investigate the effects of RO20-1724 on repetitive ketamine administration-induced learning and memory impairment in immature rats.Methods Forty-eight 21-day-old SD rats of both sexes weighing 45-55 g were randomly divided into 4 groups (n =12 each):control group(group C); ketamine group (group K); ketamine + RO20-1724 group (group K+ R) and ketamine + vehicle (ethanol) group (group K+ A).Ketamine 70 mg/kg was injected intraperitoneally (IP) once a day for 7 consecutive days in groups K,K+ R and K+ A.RO20-1724 0.5 mg/kg and equal volume of ethanol were injected IP at 30 min after IP ketamine once a day for 7 consecutive day in groups K + R and K + A respectively.Morris water maze test was used to assess learning and memory ability.The escape latency and the number of times of passing the safe zone were recorded.The animals were killed after water maze test and their brains removed for microscopic examination of hippocampus and determination of p-CREB protein expression in hippocampus (by Western blot).Results Repetitive ketamine administration significantly prolonged the escape latency,decreased the number of times of passing the safe zone and down-regulated the expression of p-CREB protein in hippocampus on the 3rd and 4th day in group K as compared with group C.RO20-1724 significantly attenuated the above changes induced by repetitive ketamine administration in group K + R as compared with group K.Electron microscopic examination showed that RO20-1724 significantly ameliorated repetitive ketamine administration-induced hippocampal neuronal damage.Conclusion RO20-1724 can ameliorate cognitive dysfunction induced by repetitive ketamine administration.Up-regulation of cAMP /CREB signaling pathway is involved in the mechanism.
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ObjectiveTo investigate the incidence and the cause of chronic pain in maintenance hemodialysis(MHD) patients,and the effect of chronic pain on quality of life.Methods Seventy MHD patients in dialysis centre of our hospital were enrolled in the study and divided into 2 groups according to pain symptoms.There were 32 patients with chronic pain in pain group,and 38 patients without chronic pain in painless group.Pain degree was evaluated by numerical rating scale (NRS,1 to 10) in pain group.Parathyroid hormone (PTH),β2-microglobulin (β2-MG) and bone mineral density(BMD) of all the patients were measured.Depression and insomnia degrees were examined by Beck depression index (BDI) and Pittsburgh sleep quality index (PSQI) respectively.Correlations were performed among parameters.Results The incidence of chronic pain in MHD patients was 45.7％ and the mean pain intensity of NRS was 5.71±1.86(95％ CI,5.04-6.38).There were significant differences of PTH,BMD,β2-MG,BDI score and PSQI score between two groups(all P＜0.01).The painful degree was positively correlated with levels of PTH and β2-MG,and the scores of PSQI and BDI,and was negatively correlated with BMD in pain group.Conclusion Chronic pain is common in MHD patients with different location and moderate degree,which can aggravate the depression and insomnia and may be associated with the changes of PTH,β2-MG and BMD.