脊髓TLR4/p38MAPK级联活化介导持续性术后痛时TNF-α的增加

目的:研究脊髓肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)在持续性术后痛中的作用及与Toll样受体4(TLR4)/p38有丝分裂原活化蛋白激酶(p38MAPK)级联的关系。方法:选择鞘内置管成功的雄性SD大鼠120只,采用随机数字表法随机分为5组(每组24只):假手术组、持续性术后痛组、Toll样受体4小干扰RNA组(TLR4 si RNA组)、4-(4-氟苯基)-2-(4-甲磺酰基苯基)-5-(4-吡啶基)咪唑组(SB203580组)和重组人Ⅱ型肿瘤坏死因子组(rh TNFR-Fc组)。按Flatters介绍的方法建立大鼠皮肤肌肉切口牵拉(skin/muscle incision and retraction,SMIR)持续性术后痛模型;在术前1天及术后第1、3、7、12和22天时测定大鼠机械缩足反应阈值(mechanical withdrawal threshold,MWT);按ELISA法测定脊髓TNF-α含量。结果:与术前基础值及假手术组比较,持续性术后痛组大鼠在术后第3、7、12和22天MWT明显降低(P<0.05),脊髓TNF-α含量在术后7、12和22天明显升高(P<0.05);与持续性术后痛组比较,TLR4 si RNA组和SB203580组大鼠在术后第3、7和12天,rh TNFR-Fc组在术后第7和12天MWT明显升高(P<0.05),TLR4 si RNA组、SB203580组和rh TNFR-Fc组大鼠脊髓TNF-α含量在术后第7、12和22天明显降低(P<0.05)。结论:脊髓TNF-α参与了大鼠SMIR持续性术后痛的形成,其增加与脊髓TLR4/p38MAPK级联的活化有关。     

加巴喷丁联合吗啡对神经病理性疼痛大鼠脊髓胶质原纤维酸性蛋白表达的影响

目的:观察加巴喷丁联合吗啡镇痛对坐骨神经慢性压迫(CCI)大鼠脊髓背角胶质原纤维酸性蛋白(GFAP)表达的影响。方法:选择重量在180～220g的成年雄性SD大鼠24只,随机分为4组(n=6):假手术组(S组)、模型组(M组)、预防性镇痛组(P组)和常规镇痛组(N组)。M组、P组和N组采用CCI建立神经病理性疼痛模型,P组在术前1d至手术后9d使用加巴喷丁联合吗啡镇痛,N组在手术当日至手术后第9天加巴喷丁联合吗啡镇痛,S组和M组仅给予生理盐水。分别于手术后第3、5、7、9天测定各组50%机械刺激缩足阈值,手术后第10天采用免疫组化测定脊髓GFAP表达。结果:与M组相比,P组和N组50%缩足阈值升高,同时脊髓背角GFAP表达降低(M组:0.6237±0.04903,P组:0.4616±0.03890,N组:0.5215±0.02691)。结论:加巴喷丁联合吗啡可以减轻CCI神经病理性疼痛和脊髓背角GFAP的表达。     

芍药苷通过抑制脊髓CC趋化因子配体2拮抗吗啡镇痛耐受

目的探讨脊髓CC趋化因子配体2(CCL2)在芍药苷拮抗大鼠慢性吗啡镇痛耐受中的作用。方法成功鞘内置管清洁级Sprague-Dawley(SD)大鼠60只,随机分为4组(n=15):生理盐水组(NS组),吗啡组(MOR组),芍药苷组(PF组)和吗啡+芍药苷组(MOR+PF组)。连续7d鞘内注射15μg吗啡建立慢性吗啡耐受的动物模型。应用甩尾潜伏期法(tail flick latency,TFL)及机械反射阈值法(mechanical withdrawal threshold,MWT)观察鞘内注射芍药苷对吗啡镇痛耐受的影响;应用免疫组织荧光染色法检测芍药苷对腰段脊髓小胶质细胞活化的影响;应用免疫印迹法(Western blot)检测芍药苷对腰段脊髓CCL2表达的影响。结果连续7d鞘内注射吗啡后,与NS组比较,MOR组大鼠腰段脊髓背角小胶质细胞显著增多,腰段脊髓CCL2表达显著增加(P0.05);而与MOR组比较,MOR+PF组大鼠腰段脊髓背角小胶质细胞显著减少,腰段脊髓CCL2表达显著减少(P0.05)。与MOR组大鼠最大镇痛效应百分率(percent of maximal possible potential effect,MPE)比较,MOR+PF组大鼠%MPE显著增加(TFL:19%±4%vs 41%±3%;MWT:18%±6%vs 42%±4%,P0.05)。结论芍药苷可能通过抑制脊髓内CCL2表达增加拮抗大鼠慢性吗啡镇痛耐受。     

单关节炎诱导胶质细胞在大鼠颈、胸、腰、骶段脊髓背角的活化

目的:探讨小胶质细胞和星形胶质细胞在单关节炎大鼠颈、胸、腰、骶段脊髓背角的活化.方法:16只SD雄性大鼠随机均分为正常对照组和单关节炎组(n=8).左侧踝关节腔注射完全弗氏佐剂(complete Freund' s adjuvant,CFA)建立单关节炎模型.分别采用Hargreaves’法和von Frey纤毛测定单关节炎大鼠双侧后爪致炎前及致炎后3d的热刺激缩爪反应潜伏期(paw withdrawal latency,PWL)、机械刺激抬腿反应阈值(paw withdrawal threshold,PWT).行为学测定结束后,每组取4只大鼠,灌注后取脊髓颈、胸、腰、骶段,采用免疫荧光组织化学法检测Iba-1(小胶质细胞标记物)和GFAP(星形胶质细胞标记物)在大鼠脊髓背角的表达情况.结果:单关节炎组大鼠致炎侧后爪的PWL和PWT值在致炎3d后均显著低于对照组(P＜0.01),对侧后爪差异无显著性(P＜0.05).单关节炎组大鼠致炎3d后,Iba-1和GFAP的荧光强度在颈、胸、腰段脊髓的双侧背角相较于对照组均明显增高,差异有显著性(P＜ 0.05或P＜0.01),而在骶段无统计学差异(P＜0.05),但有明显增加趋势.致炎侧和对侧脊髓背角Iba-1和GFAP的荧光强度在颈、胸、腰、骶各节段差异均无统计学意义(P＜0.05).结论:单关节致炎导致大鼠患侧后爪出现触诱发痛和热痛觉过敏,并诱导小胶质细胞和星形胶质细胞在大鼠颈、胸、腰段双侧脊髓背角的活化.     

鞘内注射GDNF对神经病理性疼痛大鼠脊髓水平p-Shc表达的影响

目的:探讨神经病理性疼痛大鼠脊髓背角水平p-Shc的表达变化及鞘内注射胶质细胞源性神经营养因子(glial cell line-derived neurotrophic factor,GDNF)对其表达的影响。方法:实验1:雄性SD大鼠随机分为假手术(sham)组和CCI组。CCI组又分为术后1 d组(D1组)、3 d组(D3组)、7 d组(D7组)和14 d组(D14组),分别于术后1、3、7、14 d测定热缩足潜伏期(thermal withdraw latency,TWL)和机械缩足阈值(mechanical withdrawal threshold,MWT)后处死并取其脊髓背角,采用Western blot方法测定Shc/p-Shc蛋白表达情况。实验2:雄性SD大鼠分为sham组、D14组、D14+PBS组、D14+GDNF组。与实验1相同的时间点测定TWL和MWT,并于第14 d处死并取其L4~5脊髓背角,采用Western blot方法检测Shc/p-Shc的表达变化。结果:与sham组相比,CCI组大鼠TWL和MWT明显降低(P<0.01);与D14组和D14+PBS组相比,D14+GDNF组大鼠TWL和MWT明显升高(P<0.01)。CCI组脊髓背角内p-Shc表达水平于术后3 d开始升高(P<0.05),一直持续到术后14 d(P<0.01);D14+GDNF组p-Shc表达水平较D14组和D14+PBS组显著下降(P<0.05)。结论:大鼠脊髓背角内接头蛋白Shc可能参与了神经病理性疼痛的发生,鞘内注射GDNF减轻神经病理性疼痛可能与降低脊髓背角Shc的磷酸化水平有关。     

鞘内注射AIP对神经病理性痛大鼠的镇痛作用及脊髓背角神经元磷酸化CREB的影响

目的:探讨钙/钙调素依赖性蛋白激酶Ⅱ(calcium/calmodulin-dependent protein kinaseⅡ,CaMKⅡ)在神经病理性疼痛中的作用。方法:坐骨神经选择性损伤(SNI)大鼠模型,随机分为4组(n=8):SNI组,Sham组,NS组,AIP组,后两组分别于术前20 min鞘内注射10μl的生理盐水或10%的AIP。于术后1d、2d、3d、4d、6d、8d、10d、14d测定大鼠机械缩足反射阈值(mechanical with-drawal threshold,MWT)。分别于术后1d、3d、7d取大鼠脊髓腰段,用免疫组织化学法(n=6)检测脊髓背角磷酸化pCaMKⅡ的表达;Western blot法(n=4)检测脊髓背角神经元细胞核内pCREB的表达。结果:术后1~3d AIP组大鼠MWT较NS组明显升高(P<0.01);术前鞘内注射AIP在术后1d、3d能够使脊髓背角pCaMKⅡ的表达减少,同时脊髓背角神经元细胞核内pCREB的表达也明显减少。结论:CaMKⅡ参与了神经病理性痛的形成,其作用部分通过CREB介导。     

鞘内注射GDNF对神经病理性疼痛大鼠脊髓水平GAD65表达的影响

目的:研究神经病理性疼痛大鼠脊髓背角谷氨酸脱羧酶65(Glutamate decarboxylase65,GAD65)的表达变化及蛛网膜下腔注射胶质细胞源性神经营养因子(glial cell line-derived neurotrophic factor,GDNF)对其表达的影响。方法:实验1:雄性SD大鼠随机分为假手术组(sham组)和坐骨神经结扎组(CCI组)。CCI组又分为术后1 d(D1)、3 d(D3)、7 d(D7)和14 d(D14)组。实验2:雄性SD大鼠随机分为:sham组、D14组、D14+GDNF组和D14+PBS组。两实验分别于实验前及CCI术后第1、3、7、14 d测定热缩足潜伏期(thermal withdrawal latency,TWL)及机械缩足阈值(mechanical withdrawal threshold,MWT),处死后取其L4~L5脊髓背角,采用Western blot方法测定GAD65蛋白表达情况。结果:与sham组相比,CCI组大鼠TWL及MWT均降低,GAD65表达水平于术后3 d开始降低,一直持续到术后14 d;与D14组和D14+PBS组相比,D14+GDNF组大鼠TWL及MWT均升高,GAD65表达水平升高。结论:神经病理性疼痛的发生机制可能和大鼠脊髓背角内GAD 65表达降低相关,而GDNF对其镇痛作用可能部分是通过增加脊髓GAD65的表达实现的。     

腹腔注射右美托咪啶对神经病理性疼痛大鼠镇痛的实验研究

目的:评价右美托咪啶对神经病理性疼痛大鼠行为学、痛敏及脊髓背角神经元磷酸化胞外反应激酶(phosphorylated extracellular regulated protein kinases,p ERK)、磷酸化c AMP反应元件结合蛋白(phosphorylated c AMP response element bound protein,p CREB)、c-fos蛋白表达的影响。方法:健康成年雄性Wistar大鼠54只,6~8周龄,体重180~220 g,采用随机数字表法,将其分为3组(n=18):假手术组(S组)、慢性神经病理性疼痛组(C组)和右美托咪啶组(D组)。S组仅分离坐骨神经但不结扎,C组和D组采用结扎坐骨神经的方法制备大鼠坐骨神经慢性压迫性损伤(chronic constriction injury,CCI)的神经病理性疼痛模型,D组于术后即刻开始至处死前1d腹腔注射右美托咪啶50μg/kg,1次/d,S组和C组注射等容量生理盐水。于术前1 d、术后3、7、14 d时以缩足阈值(paw withdrawal threshold,PWT)测定大鼠机械痛阈和辐射热的缩足潜伏期(paw withdrawl latency,PWL)测定大鼠的热痛阈,并于术后测定痛阈后灌注处死大鼠,取L4~6脊髓组织,采用免疫组织化学法检测脊髓背角神经元p ERK、p CREB、c-fos的表达水平。结果:与S组比较,C组和D组术后3、7、14 d时MWT降低,TWL缩短,脊髓背角p ERK、p CREB、c-fos表达上调(P<0.05);与C组比较,D组术后3、7、14 d时MWT升高,TWL延长,脊髓背角p ERK、p CREB、c-fos表达下调(P<0.05)。与术前1 d比较,C组和D组术后3、7、14 d时MWT降低,TWL缩短;与术后3 d时比较,C组和D组7、14 d时MWT降低,TWL缩短,脊髓背角p ERK、p CREB、c-fos表达上调(P<0.05)。结论:右美托咪啶可减轻大鼠慢性神经病理性疼痛,抑制p ERK、p CREB、c-fos的表达可能是其作用机制之一。     

慢性坐骨神经结扎神经痛大鼠脊髓nNOS阳性神经元的表达

目的:探讨慢性坐骨神经结扎(CCI)神经病理性疼痛大鼠脊髓背角nNOS阳性神经元的表达。方法:SD大鼠40只,随机分为五组,每组8只,即naive组、sham组、CCI5d组、CCI10d组;CCI15d组;测定各组大鼠机械缩腿阈值(MWT)和热缩腿潜伏期(TWL);同时sham组大鼠在术后5d、CCI各组分别在术后5d、10d、15d断头处死取脊髓腰膨大,采用免疫组化法测定脊髓背角nNOS阳性神经元的表达。结果:CCI大鼠在手术后形成稳定的痛敏,与naive组和sham组大鼠比较有显著差异;naive组大鼠和sham组大鼠脊髓背角仅见少量nNOS阳性神经元的表达,且两组间无统计学意义;CCI各组大鼠脊髓背角nNOS阳性神经元的表达明显增多,与naive组和sham组比较差异显著。结论:慢性坐骨神经结扎(CCI)神经痛大鼠脊髓背角nNOS阳性神经元的表达增加,脊髓背角nNOS可能参与了CCI大鼠神经病理性疼痛的形成。     

蛋白激酶Cε对大鼠背根神经节持续受压后背角星型胶质细胞激活和机械痛敏的影响

摘要 目的：探讨大鼠背根神经节持续受压(chronic compression of the dorsal root ganglion,CCD)后,脊髓背角星型胶质细胞的激活情况,以及PKCε是否可以通过调节星型胶质细胞的活性而参与CCD后神经病理性疼痛。 方法：将大鼠随机分为 6组,每组大鼠8只：假手术组、CCD7天组、CCD14天组、CCD7天+BIM I组、CCD+DMSO组、CCD+PDBu组,分别通过鞘内注射不同药物,或对正常大鼠鞘注DMSO/PDBu后,测量大鼠机械刺激缩爪阈值（paw withdrawal mechanical threshold,PWMT）的变化,利用Western Blot技术检测脊髓背角PKCε和GFAP蛋白表达的变化,利用免疫荧光技术检测脊髓背角星型胶质细胞激活情况。 结果：CCD术后第4天,鞘内注射PKCε的激动剂PDBu 1—4h,明显降低CCD大鼠PWMT（P<0.05）,而给予BIM I 1—4h,可升高CCD大鼠PWMT（P<0.05）。从CCD术后第4天起,连续3天鞘注BIM I,可明显缓解大鼠的机械痛敏（4天,P<0.05）,但从停止注射后镇痛作用消失（P>0.05）。与假手术组比较,CCD后7天和14天,手术侧背角PKCε和GFAP表达升高,差异有显著性意义(P<0.05),星型胶质细胞激活增加,而注射BIM I可明显抑制PKCε和GFAP表达(P<0.05)和星型胶质细胞激活。PDBu可导致正常大鼠PWMT明显降低（P<0.05）,GFAP蛋白质表达量增加（P<0.05）,促进星型胶质细胞激活。 结论：大鼠背根神经节持续受压后,机械痛阈下降的同时,手术侧脊髓背角内PKCε和GFAP蛋白表达上调,星型胶质细胞激活增加。PKCε可能通过调节星型胶质细胞激活参与CCD后病理性神经痛的中枢敏化机制。     

氯胺酮对神经病理性疼痛大鼠脊髓P2X_4受体mRNA表达的影响

目的:研究氯胺酮对神经病理性疼痛大鼠脊髓P2X_4受体mRNA表达的影响.方法:雄性SD大鼠45只,体重180～220g,随机分为假手术组(S组)、对照组(C组)和氯胺酮Ⅰ、Ⅱ、Ⅲ组(KⅠ、Ⅱ、Ⅲ组),每组9只.S组大鼠仅分离坐骨神经但不结扎,其余组建立坐骨神经慢性压迫性损伤(CCI)模型,K Ⅰ、Ⅱ、Ⅲ组分别于CCI后3d开始至取材点每天腹腔注射氯胺酮5mg/kg、10mg/kg、20mg/kg;S组和C组注射相同体积的生理盐水.各组大鼠分别于术前1d,术后3d、7d、14d、21d测定大鼠机械性痛觉过敏(MWT)和热痛觉过敏(TWL).各组均分别于CCI术后7d、14d、21d取3只大鼠,测定痛阈后处死,取L_(4～5)脊髓组织,用逆转录PCR(RT-PCR)方法测定P2X_4受体mRNA表达水平.结果:与术前及S组比较,C组、K Ⅰ、Ⅱ、Ⅲ组术后3d开始热痛阈及机械痛阈显著降低(P＜0.05).与C组比较,K Ⅰ、Ⅱ、Ⅲ组术后7d,14d,21d热痛阈及机械痛阈显著升高(P＜0.05).与S组比较,C组、K Ⅰ、Ⅱ、Ⅲ组大鼠脊髓P2X_4受体表达在术后7d、14d、21d均显著增加(P＜0.05);与C组大鼠比较,K Ⅰ、Ⅱ、Ⅲ组脊髓P2X_4受体表达明显减少(P＜0.05).结论:腹腔注射氯胺酮可抑制慢性神经痛大鼠痛觉过敏,该作用可能是通过作用于P2X_4受体介导的.     

Characterization of a model of persistent postoperative pain evoked by skin/muscle incision and retraction (SMIR)

Various surgical procedures, e.g. thoracotomy and inguinal hernia repair, frequently evoke persistent pain lasting for many months following the initial surgery. The essential prolonged tissue retraction required during such surgeries may account for the persistence and high incidence of postoperative pain in these patient populations. This study describes a new rat model of persistent postoperative pain evoked by skin/muscle incision and retraction (SMIR), akin to a clinical procedure. Under anaesthesia, skin and superficial muscle of the medial thigh were incised and a small pair of retractors inserted. This tissue was retracted for 1h causing potential stretch of the saphenous nerve. SMIR surgery evoked persistent significant mechanical hypersensitivity to von Frey stimulation of the plantar ipsilateral hindpaw, compared to either pre-surgery responses or concurrent responses of sham-operated rats. SMIR-evoked mechanical hypersensitivity was observed by postoperative day 3, most prominent between postoperative days 10 and 13, persisted until at least postoperative day 22 and had dissipated by postoperative day 32. Overall, mechanical sensitivity of the SMIR contralateral paw and the sham ipsilateral paw did not significantly change from pre-surgery responses. SMIR did not evoke significant heat hyperalgesia or cold allodynia. Light microscopy of saphenous nerve sections did not show degeneration or oedema in the saphenous nerve at, or proximally or distally to, the surgical site. In addition, very little to no degeneration was detected with ATF3 staining in DRG from SMIR-operated rats. These data suggest that prolonged retraction of superficial tissue evokes a persistent pain syndrome that is not driven by neuronal damage.     

A placebo-controlled randomized clinical trial of perioperative administration of gabapentin, rofecoxib and their combination for spontaneous and movement-evoked pain after abdominal hysterectomy

Current treatments for post-injury movement-evoked pain are inadequate. Non-opioids may complement opioids, which preferentially reduce spontaneous pain, but most have incomplete efficacy as single agents. This trial evaluates efficacy of a gabapentin-rofecoxib combination following hysterectomy. In addition to IV-PCA morphine, 110 patients received either placebo, gabapentin (1800 mg/day), rofecoxib (50 mg/day) or a gabapentin-rofecoxib combination (1800/50 mg/day) starting 1 h pre-operatively for 72 h. Outcomes included pain at rest, evoked by sitting, peak expiration and cough, morphine consumption and peak expiratory flow (PEF). For placebo, gabapentin, rofecoxib and combination, 24 h pain (100 mm VAS) was: at rest-23.6 (P<0.05 vs. all treatments), 13.8, 14.4 and 12.1; during cough-50.7 (P<0.05 vs. all treatments), 41.5, 44.8 and 30.8; 48 h morphine consumption (mg) was: 130.4 (P<0.05 vs. all treatments), 81.7, 75.6 and 57.2 (P<0.05 vs. gabapentin and rofecoxib) and 48 h PEF (% baseline) was: 63.9 (P<0.05 vs. all treatments), 77.2, 76.7 and 87.5 (P<0.05 vs. gabapentin and rofecoxib). Adverse effects were similar in all groups except sedation which was more frequent with gabapentin. Combination and rofecoxib reduced pain interference with movement, mood and sleep (P<0.05) and combination was superior to gabapentin for all these three (P<0.05). These data suggest that a gabapentin-rofecoxib combination is superior to either single agent for postoperative pain. Other benefits include opioid sparing, reduced interference with movement, mood and sleep and increased PEF suggesting accelerated pulmonary recovery. Future research should identify optimal dose-ratios for this and other analgesic combinations.     

脊髓背角神经元凋亡在炎性痛大鼠吗啡耐受中作用研究

目的:探讨NMDAR及谷氨酸转运体(GT)在阿片耐受机制中的作用,以及脊髓神经元凋亡在慢性阿片耐受形成机制中的意义.方法:将60只健康雄性SD大鼠行鞘内置管后随机分为6组(n=10),空白对照组(A)于左后足踝关节腔注射生理盐水50μl,其他5组注射CFA 50μl.3d后分别经鞘内给予生理盐水10μl(A和B)、吗啡10μg(C组)、吗啡20μg(D组)、吗啡10μg+NMDA受体抑制剂MK-801 10nM(E组)、吗啡10μg+GT抑制剂PDC10μg(F组),1日2次,连续给药7 d.检测大鼠左后肢机械缩爪阈值评价其痛行为学,于给药后第7天取出左侧腰膨大处脊髓进行TUNEL染色和Western blotting检测.结果:C、D两组关节炎大鼠在鞘内给予吗啡第7天形成较稳定的吗啡耐受,MK-801和PDC分别对吗啡耐受的机械痛敏具有抑制和促进作用.B组大鼠脊髓背角凋亡细胞数及凋亡相关蛋白表达与A组比较,差异无统计学意义.与B组比较,C、D组大鼠脊髓背角的凋亡细胞数显著增加(P＜0.01),Bax和caspase-3蛋白表达上调(P＜0.01),Bcl-2表达下调(P＜0.01).与C组比较,E组大鼠脊髓背角凋亡细胞显著减少(P＜0.05),Bax和caspase-3蛋白表达下调(P＜0.01),Bcl-2表达上调(P＜0.05);F组凋亡细胞增多(P＜0.01),Bax和caspase-3蛋白表达上调(P＜0.01),Bcl-2表达下调(P＜0.01).结论:脊髓神经元凋亡可能是慢性阿片耐受的神经基础,NMDAR及GT在阿片耐受的神经细胞凋亡过程中发挥作用.     

鞘内注射维生素B_6对大鼠慢性神经痛的镇痛作用及对DRG神经元p-ERK表达的影响

目的:观察维生素B_6(VitB_6)对神经病理性疼痛大鼠机械痛敏、热痛敏及L4～L5背根神经节(DRG)磷酸化细胞外信号调节激酶(P-ERK)表达的影响.方法:选择6只正常SD大鼠作为对照组(control),另选择鞘内置管3天后无神经损伤症状的SD雄性大鼠54只,随机分为3组(n=18):假手术组(sham):只分离坐骨神经;CCI组:结扎坐骨神经;CCI+Vit B6组:坐骨神经结扎后鞘内注射VitB_610mg/kg/d,连续两周.各组术前2天和术后1、3、5、7、10、14天测定各组大鼠热缩足反射潜伏期(TWL)、机械缩足反射阈值(MWT).除control组外其余各组分别在术后3d、7d和14d处死大鼠,采用免疫组织化学法观察L4～5 DRG和p-ERK的表达.结果:与sham组比较,CCI组术后各天TWL、MWT明显降低(P＜0.01);与CCI组比较,CCI+VitB_6组术后3、5、7、10、14天TWL明显增高(3天P＜0.05,5、7、10、14天P＜0.01),而术后各天MWT无明显差别.术后3、7、14天,CCI组结扎侧L4,5背根节p-ERK阳性细胞率明显高于sham组(P＜0.01),CCI+Vit B_6组结扎侧L4,5背根节p-ERK阳性细胞率明显低于CCI组(P＜0.01).结论:背根神经节ERK活化参与神经病理性疼痛信号传递,鞘内注射Vit B_6抑制CCI大鼠热痛敏,其机制可能包括通过上游机制抑制ERK激活.     

鞘内注射醋酸泼尼松龙对背根节压迫大鼠的镇痛作用及其机制的探讨

目的：研究鞘内注射醋酸泼尼松龙（PA）对背根节慢性压迫（CCD）大鼠痛阈和脊髓背角nNOS表达的影响及其镇痛机制.方法：鞘内置管手术成功雄性SD大鼠100只,随机分为7天组和15天组两组,每组再随机分为假手术（Sham）组,人工脑脊液（ACSF）组,鞘内注射PA 0.5、1.0、2.0mg/kg组（n=10）.分别于CCD术前（0）及术后1,3,5,7,9,11,13,15天采用von Frey纤毛机械刺激法和热辐射刺激法评定大鼠机械刺激缩足反射阈值（PWMT）和热刺激缩足反射潜伏期（PWTL）;术后第7天和第15天运用免疫组织化学法和Western blot法观察脊髓背角nNOS表达的变化.结果：与术前基础阈值相比,除假手术组外,CCD术后各组的PWMT和PWTL均出现明显地下降（P＜0.01）,各组间无明显差异（P＞0.05）.术后第5天开始,PA 2.0 mg/kg组与ACSF组相比,PWMT和PWTL显著升高（P＜0.05）.免疫组织化学方面,背根节压迫后第7和第15天,ACSF组与PA 0.5、1.0 mg/kg组脊髓背角阳性神经元数量明显增多,三组之间比较无显著差异（P＞0.05）.PA 2.0 mg/kg组和ACSF相比,第7天和第15天均显著降低（P＜0.01）.脊髓背角Westernblot检测与免疫组织化学的结果基本一致.结论：鞘内注射PA有镇痛作用,其作用机制可能与抑制脊髓背角nNOS的表达有关.     

术前给予巴氯酚延迟坐骨神经松结扎神经病理痛的形成

目的研究术前鞘内注射GABAB受体激动剂巴氯酚(Bac)对慢性神经病理痛大鼠痛阈的影响,探讨脊髓GABA能系统在神经病理痛调节中的作用。方法建立慢性坐骨神经结扎损伤模型(CCI),SD大鼠32只随机分成4组:假手术组,大鼠左侧坐骨神经分离,但不结扎,术前鞘内注射生理盐水10μL;神经结扎组,大鼠左侧坐骨神经松结扎,术前鞘内注射生理盐水10μL;Bac 1组,大鼠左侧坐骨神经松结扎前10 min,鞘内注射Bac 0.03μg;Bac 2组,大鼠左侧坐骨神经松结扎前10min,鞘内注射Bac 0.3μg。术后第1、3、5、7、10、14天测大鼠机械刺激缩足反射阈值(MWT)和热刺激缩足反射潜伏期(TWL)以及运动功能。结果术后第1~14天神经结扎组大鼠MWT和TWL较假手术组大鼠明显降低(P<0.05);术前给Bac 0.3μg的坐骨神经结扎大鼠与术前给生理盐水的坐骨神经结扎大鼠比较,术后第1~5天MWT和TWL明显升高(P<0.05)。结论坐骨神经结扎前鞘内注射Bac 0.3μg可延缓大鼠神经病理性疼痛的形成。     

Intrathecal morphine compared with diamorphine for postoperative analgesia following unilateral knee arthroplasty

Objectives: To compare the efficacy and side effects of low dose intrathecal morphine and diamorphine for postoperative analgesia after total knee arthroplasty.Methods: Sixty-four patients were included in a prospective, randomised, double-blind study. Following a standardised general anaesthetic technique, patients received either 0.3 mg of intrathecal morphine or diamorphine with 2–2.5 ml of 0.5% heavy spinal bupivacaine. Supplementary analgesia was provided postoperatively by regular eight hourly diclofenac and patient controlled IV morphine (bolus 1 mg, lockout 5 min, no background infusion).Results: Patients in the morphine group had significantly lower median numerical rating score (NRS) for pain on movement at 4 h [0 versus 3.5] (P=0.0008) and 8 h [0 versus 4] (P=0.0083). In addition, median PCA morphine consumption was significantly reduced at 4 h [0 versus 1] (P=0.0005), 8 h [0.5 versus 6] (P=0.0063) and 12 h [3 versus 8.5] (P=0.0426) in the morphine group. There was no significant difference in the total morphine consumption or NRS for pain at 24 h between the two groups. There was no significant difference in the incidence of side effects between the two groups.Conclusion: In the doses used in this study, morphine produced more effective analgesia than diamorphine in the early postoperative period with comparable side effects [Acute Pain 4 (1) (2001) 7].     

The effectiveness of spinal and systemic morphine on rat dorsal horn neuronal responses in the spinal nerve ligation model of neuropathic pain

The treatment of pain arising from nerve injury can be difficult and the opioid sensitivity of neuropathic pain remains debatable. Clinical and animal studies report a wide range in the effectiveness of morphine, ranging from inadequate to potent analgesia. In this electrophysiological study we compare the effectiveness of spinal versus systemic administration of morphine on the natural and electrically evoked responses of spinal neurones of rats with a selective spinal nerve (L5/6) ligation. Recordings were made 1 week and/or 2 weeks after ligation. We have also compared the effects of morphine, by the two routes, on normal and sham operated animals. In spinal nerve ligated rats, morphine (0.1-5 microg) administered via the intrathecal route produced greater dose-dependent inhibitions of the neuronal responses compared with those produced by the systemic route (1-6 mg/kg). The dose response curves for intrathecal morphine on the C-fibre evoked and noxious natural stimuli evoked neuronal responses (mechanical and thermal) of spinal nerve ligated rats were to the left of those of sham operated and normal rats, suggesting an enhanced potency of intrathecal morphine after nerve injury. This was clearest for the lower doses of the opioid. The effects of spinal morphine on the responses to low intensity stimuli were similar in all groups of rats. In contrast to the spinal route, systemic morphine was less effective in inhibiting the evoked neuronal responses of spinal nerve ligated rats. This was especially clear for the C-fibre evoked and noxious natural stimuli evoked responses (mechanical and thermal) of spine nerve ligated rats. Our results suggest that the effectiveness of morphine may be partly related to the timing of the treatment relative to the duration of the neuropathy, the route of administration and also the neuropathic symptom. Spinal opioids may be a useful approach to pain control in neuropathic pain states where systemic routes produce inadequate analgesia.     

Forced Treadmill Running Suppresses Postincisional Pain and Inhibits Upregulation of Substance P and Cytokines in Rat Dorsal Root Ganglion

Exercise causes a variety of psychophysical effects (eg, alterations in pain sensation). Tissue injury induces mediator releases in the spinal cord resulting in pain hypersensitivity; however, the contribution of the dorsal root ganglion (DRG) is poorly understood. In this study, we tested if forced treadmill running can attenuate postoperative pain and alter substance P (SP) or proinflammatory cytokine level in the DRG by using a rat model of skin/muscle incision and retraction (SMIR). We evaluated mechanical sensitivity to von Frey stimuli (6 and 15 g) and expression of SP, interleukin-1β, and interleukin-6 in the DRG of sham-operated sedentary rats, SMIR sedentary rats, sham-operated rats with forced treadmill running, and SMIR rats with forced treadmill running. At postoperative day 8, trained rats ran for 5 days per week for 4 weeks on a treadmill 70 minutes/d with an intensity of 18 m/min. On postoperative day 6, SMIR sedentary rats displayed a significant mechanical hypersensitivity that persisted until postoperative day 35. By comparison, SMIR-operated rats, which received forced treadmill running, exhibited a quick recovery from mechanical hypersensitivity. SMIR sedentary rats showed an upregulation of SP, interleukin-1β, and interleukin-6 in the DRG at postoperative days 14 and 28, whereas SMIR-operated rats receiving forced treadmill running reversed this upregulation at postoperative day 28. We concluded that forced treadmill running alleviated persistent postincisional pain caused by SMIR surgery. This appears to be protective against postoperative pain, which probably relates to the downturn in excess SP, interleukin-1β, and interleukin-6 in the DRG.PerspectiveControlling the expression of SP, interleukin-6, and interleukin-1β in the DRG can help manage postoperative pain. This finding could potentially help clinicians and physical therapists who seek to examine how exercise may attenuate postsurgical pain and its mechanism.