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Objective To evaluate the relationship between hydrogen sulfide (H2S) and P2X3 receptors in dorsal root ganglions (DRGs) of rats with neuropathic pain (NP).Methods Thirty-six healthy male Sprague-Dawley rats,aged 4-6 weeks,weighing 180-200 g,in which IT catheters were successfully implanted,were divided into 3 groups (n=12 each) using a random number table method:sham operation group (group S),group NP and endogenous H2S synthase (cystathionine beta-syntheses [CBS]) inhibitor animooxyacetic acid (AOAA) group (group A).NP was induced by chronic constriction injury (CCI) to the sciatic nerve at 3 days after IT catheters were successfully implanted.AOAA (10 μg/kg) 10 μl and normal saline 10 μl were intrathecally injected once a day for 14 consecutive days starting from 1 day after CCI in group A,and normal saline 20 μl was intrathecally injected instead in S and NP groups.At 1 day before CCI and 1,3,7,10 and 14 days after CCI,the thermal paw withdrawal latency (TWL) and mechanical paw withdrawal threshold (MWT) were measured at 30 min after intrathecal injection.The animals were sacrificed at 7 and 14 days after CCI,and ipsilateral DRGs of the lumbar segment (L4-6) were removed for detection of the expression of CBS and P2X3 receptors by Western blot.Results Compared with group S,the TWL was significantly shortened,MWT was decreased,and the expression of CBS and P2X3 receptors in DRGs was up-regulated at each time point after CCI in group NP (P＜0.05).Compared with group NP,the TWL was significantly prolonged,the MWT was increased,and the expression of CBS and P2X3 receptors in DRG s was down-regulated at each time point after CCI in group A (P＜0.05).Conclusion H2S in DRG s can up-regulate the expression of P2X3 receptors,which may be involved in the pathophysiological mechanism of NP in rats.
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Objective To evaluate the role of transient receptor potential channel 8 (TRPM8) in the development and maintenance of neuropathic pain and the relationship with nuclear factor kappa B (NF-κB) in the dorsal root ganglion of rats.Methods Thirty-six pathogen-free healthy adult male SpragueDawley rats,weighing 180-200 g,aged 6-8 weeks,were divided into 3 groups (n=12 each) using a random number table:sham opeation group (group S),neuropathic pain group (group NP) and TRPM8 bocker BCTC group (group BCTC).Neuropathic pain was induced by ligation of the right sciatic nerve in anesthetized rats.BCTC 20 nmol was intrathecally injected once a day on preoperative day 1 and postoperative days 1,3,7 and 10 in group BCTC.The thermal,mechanical and cold pain thresholds were measured on preoperative day 1 and postoperative days 1,3,7,10 and 14.The dorsal root ganglions of the lumbar segment (L4-6) were removed on postoperative days 7 and 14 for determination of the expression of TRPM8 and NF-κB p65 by Western blot.Results Compared with group S,the thermal and mechanical thresholds were significantly decreased on postoperative days 1-14,and the cold pain threshold was decreased on postoperative days 3-14 in NP and BCTC groups,the expression of TRPM8 and NF-κB p65 in dorsal root ganglions was up-regulated on postoperative days 7 and 14 in group NP (P＜0.05),and no significant change was found in the expression of TRPM8 and NF-κB p65 in dorsal root ganglions in group BCTC (P＞0.05).Compared with group NP,the thermal pain threshold was significantly decreased and the cold pain threshold was increased on postoperative days 3-14,the expression of TRPM8 and NF-κB p65 in dorsal root ganglions was up-regulated on postoperative days 7 and 14,and no significant change was found in the mechanical pain threshold in group BCTC (P＞0.05).Conclusion NF-κB activation after opening of TR-PM8 in dorsal root ganglion neurons is involved in the development and maintenance of neuropathie pain in rats.
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Objective To evaluate the role of P2X3 receptors in the development and mnaintenance of neuropathic pain (NP) and the relationship with nuclear factor kappa B (NF-κB) in dorsal root ganglia of rats.Methods Thirty-six SPF healthy male Sprague-Dawley rats,weighing 180-200 g,aged 4-6 weeks,in which intrathecal catheters were successfully implanted,were divided into 3 groups (n =12 each) using a random number table:sham operation group (group S),NP group and P2X3 receptor antagonist A-317491 group (group A).At 3 days after intrathecal catheters were successfully implanted,NP was induced by chronic constriction injury to the sciatic nerve.The sciatic nerve was only exposed but not occluded in group S.Intrathecal injection was performed twice a day for 14 consecutive days starting from 1 day after operation.Normal saline 20 μ l was intrathecally injected in group S and group NP,and A-317491 100 nmol/10 μ1 and normal saline 10 μ l were intrathecally injected in group A.Thermal paw withdrawal threshold (TWT) and mechanical paw withdrawal threshold (MWT) were measured on day 1 before operation and at 30 min after intrathecal injection on days 1,3,7,10 and 14 after operation.On days 7 and 14 after operation,the rats were sacrificed and the dorsal root ganglia of the lumbar segment were removed for determination of the expression of P2X3 receptors and NF-κB p65 by Western blot.Results Compared with group S,TWT and MWT were significantly decreased at each time point after operation,and thc expression of P2X3 receptors andi NF-κB p65 in dorsal root ganglia was up-regulated on days 7 and [4 after operation in group NP (P＜0.05 or 0.01).Compared with group NP,TWT was significantly increased at each time point after operation,MWT was increased on days 3,7,10 and 14 after operation,anl the expression of P2X3 receptors and NF-κB p65 in dorsal root ganglia was down-regulated on days 7 and 14 after operation in group A (P＜0.05).Conclusion The mechanism underlying the development and maintenance of NP is related to the up-regulation of P2X3 receptor expression and promotion of the expression of NF-κB in dorsal root ganglia of rats.
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Objective To explore the relationship between the protective effect of hydrogen sulfide (H2 S ) postconditioning against myocardial hypoxia-reoxygenation and the dynamics of actin. Methods Adult rat cardiomyocytes were isolated and the same hatch cells were divided into 4 groups (n =3):normal group (group N),hypoxia-reoxygenation group (group HR),ischemia postconditioning group (group IPTC)and H2 S postconditioning group (group S).The four groups were divided into two sub-groups with or without cytochalasin D (CyD).At the end of reoxygenation,F-actin/G-actin,intracellular calcium ion concentration (Ca2+ )and pH value were detected with laser scanning confocal microscopy, meanwhile the level of p-p38MAPK was detected with Western blot.Results The fluorescence intensity of F-actin/G-actin of group HR,group IPTC and group S were significantly higher than that of group N (P <0.05).The fluorescence intensity of Ca2+ of group HR was higher than that of group N,group IPTC and group S (P <0.05);The intensity of Ca2+ of all group with CyD treatment was higher than those without (P <0.05);The fluorescence intensity of pHi of group N and group HR with CyD treatment was higher than those without;The fluorescence intensity of pHi of group IPTC and group S was lower than those without;The flu-orescence intensity of pHi of group HR was lower than that of group N,group IPTC and group S (P <0.05), respectively;the pHi of group N and group HR sub-group with CyD treatment was higher than those without correspondingly (P <0.05),however,the pHi of IPTC and S sub-groups were lower than their corresponding groups (P <0.05).The level of p-p38MAPK in group HR was significantly higher than those of other groups (P <0.05);there was no difference among groups N,IPTC and S.Conclusion Hydrogen sulfide postcondi-tioning could promote F-actin to remodel and stabilize the cellular environment.Hypoxia-reoxygenation pro-motes the phosphorylation level of p38MAPK,which could be surpressed by H2 S postconditioning.
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Objective To evaluate the effects of modified ultrafiltration on the expression of aquaporin 1 (AQP1) in cardiopulmonary bypass (CPB)-induced lung injury in dogs.Methods Eighteen healthy adult dogs of either sex,weighing 15-20 kg,were randomly divided into 3 groups (n =6 each):control group (group C),group CPB and modified ultrafiltration group (group MUF).The dogs were anesthetized with intraperitoneal 2.5％pentobarbital 25 mg/kg.Thoracotomy was performed in all the three groups and in addition lung injury was produced by CPB in CPB and MUF groups.In group MUF,modified ultrafiltration was performed at 10-15 min after termination of CPB.Arterial blood samples were collected before mechanical ventilation (T1),at end of CPB (T2),and at 1 h after termination of CPB (T3) to calculate respiration index (RI) and oxygenation index (OI).The lungs were removed for microscopic examination of pathologic changes in lung tissues under light microscope and for detection of AQP1 mRNA expression by real-time PCR.Results RI and OI were significantly higher and AQP1 mRNA expression was lower at T2 and T3 than at T1 in CPB and MUF groups (P ＜ 0.05).Compared with group C,RI was significantly increased and AQP1 mRNA expression was down-regulated at T2,3 in CPB and MUF groups,and OI at T2.3 in CPB group and at T2 in MUF group was decreased (P ＜ 0.05).Compared with group CBP,RI was significantly decreased,OI was increased and AQP1 mRNA expression was up-regulated at T3 in group MUF (P ＜ 0.05).Conclusion Modified ultrafiltration can reduce CPB-induced lung injury in dogs and upregulation of AQP1 may be involved in the mechanism.
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Objective To evaluate the role of aquaporin 1(AQPI)expression in the cartiopulmonary bypass(CPB)-induced lung injury in dogs.Methods Twenty-four healthy dogs,weighing 15-20 kg,were randomly divided into 4 group(n =6 each):control group(group C),acetazolamide Ⅰ group(group A Ⅰ),acetazolamide Ⅱ group(group A Ⅱ),and acetazolarnide Ⅲ group(group AⅢ).Lung injury was produced by CPB.The traditional priming solution was infused in group C.Priming solutions containing acetaaolamide 20,40 and 60 mg/kgwere infused in groups A Ⅰ,A Ⅱ and A Ⅲ respectively.Blood samples were collected from the femoral artery before mechanical ventilation,at the end of CPB and at 1 h after end of CPB(T1-3)for arterial blood gas analysis.Respiration index(RI)and oxygenation index(OI)were calculated.The lung specimens were oblained for determination of AQPI mRNA and protein expression(by RT-PCR and Western blot)and for microscopic examination.The pathological changes of the lung were scored.Results Compared with group C,P(A-a)O2,RI and the pathological score were significantly increased at T2.3,OI was significantly decreased at T2.3,and AQP1 protein expression was down-regulated at T2.3 in groups A Ⅰ,A Ⅱ and AⅢ,and AQP1 mRNA expression was down-regulated at T2.3 in groups AⅡ and AⅢ(P＜0.05).Compared with group A Ⅰ,P(A-a)O2,RI and the pathological score were significantly increased at T2.3,OI was significantly decreased at T2.3,and AQP1 protein expression was down-regulated at T2.3 in groups A Ⅱ and AⅢ,and AQP1 mRNA expression was down-regulated at T2.3 ingroup A Ⅲ(P ＜ 0.05).Compared with group A Ⅱ,RI and the pathological score were significantly increased at T2.3,and AQP1 protein expression was down-regulated at T2.3 in group A Ⅲ(P ＜ 0.05).Conclutsion Down-regulation of AQPI expression is involved in the CPB-induced lung injury in dogs.
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Objective To compare the myocardial protective effect of hyperpolarized cardioplegic arrest with pinacidil against that of depolarized hyperkalemic arrest during cardiopulmonary bypass Methods Eighteen healthy mongrel dogs of both sexes weighing 10 15kg were divided into three groups of six each, according to the cardioplegic solution infused into aortic root after aortic cross clamp was applied; group A received 4℃ standard St Thomas solution (K +16mmol/L); group B 37℃ St Thomas solution (K +5mmol/L) containing pinacidil (50?mol/L) mixed with blood (the ratio was 1:1);group C 4℃St Thomas solution (K + 5mmol/L) containing pinacidil(50?mol/L) mixed with blood (1∶1) The global ischemic time was 60min followed by 30min reperfusion Myocardial tissue was taken before and 30min, 60min after aortic cross clamping and 30min after reperfusion for determination of myocardial content of adenine nucleotide and MDA and ultrastructure examination with electron microscope Hemodynamics (BP,CVP,PCWP,CO,CI and LVSW) was also measured before aortic cross clamping and 15,30min after declamping Results Significant ischemic and reperfusion damages were found in group A, while there were only mild damages in group B and C Hemodynamics recovery after aortic declamping was significantly better in group C than that in group A and B Conclusions Myocardial protective effect of hyperpolarized arrest produced by blood cardioplegic solution containing pinacidil is superior to that of traditional depolarized hyperkalemic arrest and hypothermic hyperpolarized cardioplegia is better than normothermic
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Objective To compare the myocardial protective effect of pinacidil-induced hyperpolarized and hyperkalemic depolarized cardiac arrest on isolated rabbit heart under different temperature. Methods Forty-eight rabbits of both sexes weighing 2.0-2.5 kg were sacrificed by a knock on the head. Their hearts were excised and perfused in a Langendorff apparatus with an oxygenated Krebs-Hensleit buffer (KHB)(37℃). The study was divided into six groups: A normothermic hyperkalemic cardioplegia; B normothermic hyperkalemic blood cardioplegia; C hypothermic hyperkalemic cardioplegia; D hypothermia hyperkalemic blood cardioplegia; E normothermic hyperpolarizing blood cardioplegia; F hypothermic hyperpolarizing blood cardioplegia. Three pieces of myocardial tissue were obtained from apex of left ventricle at the end of the study for determination of myocardial adenine nucleotide and lipid peroxide content and microscopic examination. The following were recorded : (1) cardiac arrest time: the time from perfusion with cardioplegic solution to the beginning of cardiac arrest. (2) heart beat recovery time ;the time from reperfusion with KHB to the beginning of normal heart beat. (3) changes in HR, left ventricle developed pressure and myocardial contractility before and after cardiac arrest. Results The cardiac arrest time was longer and the time for the heart to restart was shorter in the two hyperpolarizing blood cardioplegia groups (group E and F) than that in the other 4 groups. No arrhythmia occurred in group E and F. Left ventricle developed pressure(LVDP) and left ventricle contractility recovered quickly after reperfusion with KHB was started and were restored to the pre-ischemia level after 20 min in group E and F. The levels of ATP, TAN and EC were higher and the MDA level was lower in group E and F than those in the other 4 groups. Myocardial structure was less injuried in group E and F. Conclusion The myocardial protection effect of hyperpolarizing blood cardioplegia with pinacidil is superior to traditional hyperkalemic depolarizing cardioplegia.