鞘内注射DREAM-shRNA对神经病理性痛大鼠脊髓背角p-CREB表达的影响

Objective To investigate the effects of intrathecal (IT) DREAM-short hairpin RNA (DREAM-shRNA) on expression of phosphorylated cyclic AMP response element binding protein (p-CREB) in the spinal dorsal horn in a rat model of neuropathic pain. Methods Adult male SD rats weighing 280-320 g were anesthetized with intraperitoneal 10% chloral hydrate. Neuropathic pain was induced by chronic constrictive injury (CCI) to sciatic nerve. IT catheters were placed according to the method described by Yaksh on 3rd day after CCI. Twenty-four rots in which IT catheter was successfully implanted were randomly divided into 4 groups (n = 6 each) : group Ⅰ sham operation (group S) ; group Ⅱ neuropathic pain (group NP) ; group Ⅲ RNA interference (group RNAi) and group Ⅳ blank vector (group BV). Lentivius with DREAM-shRNA 5 μl was injected IT in group RNAi, and blank vector 5 μl in group BV, and once a day for 7 days, starting from the day 8 after CCI. The mechanical pain threshold was measured at day 1 before CCI (T0 ,baseline) and day 7-14 after CCI (T1-8). The animals were killed on 15th day after CCI. The L4-6 lumbar segment of the spinal cord was removed for determination of the expression of green fluorescent protein (GFP) and p-CREB by immuno-fluorescent method.Results The mechanical pain threshold was significantly decreased as compared with the baseline at T0 in all 4 groups and returned to the baseline levels at T5-8 in group S and RNAi, but remained low in group NP and BY. The mechanical pain threshold was significantly lower after CCI/sham operation and significanty higher at T8 in group RNAi than in the other 3 groups. The expression of p-CREB in the spinal dorsal horn was up-regulated in group NP, RNAi and BV as compared with group S, and in group NP and BV as compared with group RNAi. The green fluorescence was observed in group RNAi but not in the other 3 groups. Conclusion IT DREAM-shRNA can ameliorate neuropathic pain in rats through inhibiting the expression of p-CREB in the spinal dorsal horn.     

鞘内注射DREAM-shRNA对神经病理性痛大鼠的镇痛效应

目的 评价鞘内注射转录因子下游调控元件拮抗因子-短发夹RNA(DREAM-shRNA)对神经病理性痛大鼠的镇痛效应.方法 健康雄性SD大鼠,体重280-320g,采用坐骨神经慢性缩窄性损伤(CCI)法建立大鼠神经病理性痛模型,于CCI后第3天鞘内置管.取鞘内置管成功的大鼠24只,随机分为4组,每组6只,假手术组(Sham组):仅暴露坐骨神经,不结扎;神经病理性痛组(NP组):于CCI后第8天鞘内注射生理盐水10μl;RNA干扰组(RNAi组):于CCI后第8天鞘内注射含DREAM-shRNA的慢病毒5μl、生理盐水5μl;空白载体组(BV组):于CCI后第8天鞘内注射慢病毒空白载体5μl、生理盐水5μl,连续注射7d.于CCI前1d(基础状态)、CCI后第7～14天(T1-8)测定热痛阈和机械痛阈,于CCI后第15天测定脊髓背角绿色荧光蛋白(GFP)的表达水平.结果 与基础值比较,NP组和BV组热痛阈降低,Sham组T1-4时热痛阈降低,RNAi组T1-4,6时热痛阈降低,4组CCI后各时点机械痛阈降低(P<0.05或0.01);与T1时比较,NP组和BV组其余时点热痛阈和机械痛阈降低.RNAi组T3-5,时热痛阈降低,T1时热痛阈和机械痛阈升高(P<0.05或0.01);与Sham组比较.NP组和BV组热痛阈和机械痛阈降低,RNAi组T2时机械痛阈降低,T5时升高(P<0.05),热痛阈差异无统计学意义(P>0.05);与NP组比较.RNAi组热痛阈和机械痛阈升高(P<0.05).仅RNAi组脊髓背角有GFP表达,其余3组脊髓背角未见GFP表达.结论 鞘内连续注射DREAM-shRNA可在一定程度上缓解大鼠神经病理性痛.     

鞘内注射H-89对神经病理痛大鼠脊髓背角磷酸化cAMP反应元件结合蛋白表达的影响

目的观察鞘内注射高选择性蛋白激酶A抑制剂H-89对慢性神经病理痛大鼠脊髓背角磷酸化环磷酸腺苷反应元件结合蛋白(pCREB)表达的影响。方法成年雌性SD大鼠58只,体重230-270g。采用右侧慢性坐骨神经结扎的方法建立慢性神经病理痛模型。第一部分,取28只模型大鼠随机分为4组(n=7),H1、H2、H4组分别单次鞘内注射1、2、4nmolH-89[用二甲亚砜(DMSO,10mmol/L)溶解成10μl],Con组单次鞘内注射10mmol/L　DMSO10μl。给药前和给药后15、30、60min分别测定右侧50%缩足反射阈值(MWT)和热缩足反射潜伏期(TWL)。第二部分,取24只模型大鼠随机分成4组(n=6),Con组:单次鞘内注射10mmol/L　DMSO10μl,H1、H2、H4组分别单次鞘内注射H-891、2、4nmol(10μl);另取6只大鼠实施假手术后,单次鞘内注射10mmol/LDMSO10μl(sham组)。第二部分大鼠给药后30min处死,取L4,5脊髓,免疫组织化学染色观察脊髓背角pCREB的表达。结果与给药前比较,H2组MWT给药后15min增加,H4组给药后15、30minMWT增加,TWL延长(P<0.05或0.01);与Con组比较,H2组MWT给药后15min增加,H4组给药后15、30minMWT增加,TWL延长(P<0.05或0.01)。与Con组比较,Sham、H1、H2和H4组脊髓背角pCREB免疫反应阳性神经元数量和表达降低(P<0.05或0.01)。结论鞘内注射H-89抑制了神经病理痛大鼠脊髓背角pCREB表达,PKA/CREB信号通路的激活参与了慢性神经病理痛的维持。     

鞘内注射U0126对神经痛大鼠脊髓背角磷酸化cAMP反应元件结合蛋白表达的影响

目的观察鞘内单次注射U0126(有丝分裂素激活蛋白激酶激酶的阻滞剂)对大鼠脊髓背角磷酸化cAMP反应元件结合蛋白(pCREB)表达的影响,探讨细胞外信号调节激酶(ERK)-CREB信号传递通路在神经痛中的作用。方法第一部分40只坐骨神经慢性损伤(CCI)模型大鼠随机分为5组(n=8):U1组、U2组、U3组和U4组分别鞘内注射0.2、0.5、1、和5μgU0126,C组(模型对照组)单次鞘内注射5%二甲基亚矾10μl,另取8只正常大鼠鞘内注射5.0μgU0126作空白对照组。采用vonFrey纤维丝及热痛刺激仪测定大鼠术侧后肢的机械性缩爪阈值和热刺激缩爪阈值。第二部分50只CCI模型大鼠随机分为5组(n=10):T1、T2、T3、T4组分别在鞘内注射5.0μgU0126后0.5、2、6、12h处死,CCI组为模型对照组,另取10只正常大鼠作对照组。采用免疫组织化学方法测定术侧脊髓背角pCREB免疫反应阳性神经元数量,采用免疫印记法测定脊髓背角pCREB表达。结果第一部分空白对照组注射U01265.0μg对机械性缩爪阈值和热刺激缩爪阈值没有影响。与C组比较,U1组注药后各时点及u2组注药后2、6、12、24h时大鼠术侧机械性刺激缩爪阈值及热刺激缩爪阈值差异无统计学意义(P>0.05),U2组注药后0.5h及U3组、U4组注药后0.5、2、6、12h时大鼠术侧机械性刺激缩爪阈值和热刺激缩爪阈值延长或增加(P     

鞘内注射GDNF对神经病理性痛大鼠脊髓背角p38MAPK蛋白表达的影响

目的 评价鞘内注射胶质细胞源性神经营养因子(GDNF)对神经病理性痛大鼠脊髓背角p38丝裂原活化蛋白激酶(p38MAPK)蛋白表达的影响.方法 取鞘内置管成功的健康雄性SD大鼠120只,周龄6周,体重180～200 g,随机分为4组(n=30):对照组(C组)、假手术组(S组)、神经病理性痛组(P组)和GDNF组.采用结扎L5.6脊神经的方法建立大鼠神经病理性痛模型.C组不给予任何处理;S组只暴露脊神经,但不结扎;P组脊神经结扎后鞘内注射生理盐水10μl,隔日1次,连续14 d;GDNF组脊神经结扎后鞘内注射GDNF 2μg,用生理盐水稀释至10μl,隔日1次,连续14 d.分别于脊神经结扎后3、7和14 d时,取10只大鼠,测定机械痛阈,然后处死,取脊髓背角,分别采用免疫组化法和蛋白质印迹法测定p38MAPK蛋白的表达水平.结果 与S组比较,P组和GDNF组机械痛阈降低,脊髓背角p38MAPK蛋白表达上调(P＜0.05或0.01);与P组比较,GDNF组机械痛阈升高,脊髓背角p38MAPK蛋白表达下调(P＜0.05或0.01).结论 鞘内注射GDNF可通过抑制脊髓背角p38MAPK蛋白的表达减轻大鼠神经病理性痛.     

鞘内注射P300 siRNA对神经病理性痛大鼠的镇痛效果

目的 评价鞘内注射p300小干扰RNA(p300siRNA)对神经病理性痛大鼠的镇痛效果.方法 取鞘内置管成功的雄性SD大鼠96只,采用坐骨神经慢性压迫性损伤法(CCI)建立神经病理性痛模型,随机分为4组(n=24):假手术+生理盐水组(S组)、CCI+生理盐水组(CCI组)、CCI+转染试剂组(V组)和CCI+p300siRNA组(P组).于术后3～6 d时鞘内注射生理盐水、转染试剂或p300siRNA(siRNA 4μg溶于转染试剂)各20μl,2次/d,10μl/次,连续4 d.于术前1 d(基础状态)、术后1、3、5、7、9、11、14 d时测定机械痛阈和热痛阈;于术后3、7、14 d时取腰段脊髓,测定p300蛋白及其mRNA、乙酰化组蛋白H3(Ac-H3)的表达.结果 与基础值比较,CCI组、V组和P组术后各时点机械痛阈和热痛阈降低(P＜0.05).与S组比较,其余各组机械痛阈和热痛阈降低,p300蛋白及其mRNA和Ac-H3蛋白表达上调(P＜0.05).与CCI组比较,P组机械痛阈和热痛阈升高,p300蛋白及其mRNA和Ac-H3蛋白表达下调(P＜0.05).结论 鞘内注射p300 siRNA可减轻大鼠神经病理性痛,其机制与抑制脊髓p300和Ac-H3蛋白的表达有关.     

慢性神经病理性疼痛大鼠背根神经节和脊髓背角pCREB表达的变化

目的 探讨背根神经节和脊髓背角磷酸化cAMP反应元件结合蛋白（pCREB）表达在慢性压迫性神经损伤（CCI）致神经病理性疼痛大鼠痛觉过敏中的作用。方法 成年雌性SD大鼠32只，体重230-270g，随机分为4组（n=8）：空白组、sham组、CCI 2w组和CCI 4w组。CCI前测定痛阈[机械缩足反射阈值（MWT）和热缩足反射潜伏期（TWL）]基础值，CCI后（空白组、sham组和CCI 2w组于CCI 14d；CCI 4w组于CCI28d）再次测定痛阈。最后一次测定痛阈后次日，取I4-5脊髓和I5背根神经节，免疫组织化学染色，计数pCREB免疫反应阳性（pCREB-IR）神经细胞数量。结果 MWT：CCI后sham组、CCI2w组、CCI 4w组均低于基础值，CCI后sham组低于空白组，CCI2w组低于sham组（P〈0．01）；1wL：CCI2w组短于基础值，CCI2w组短于sham组，CCI后CCI4w组长于CCI2w组（P〈0．01）。sham组背根神经节pCREB-IR神经细胞数量多于空白组，CCI2w组背根神经节及脊髓背角pCREB-IR神经细胞数量多于sham组，CCI4w组背根神经节及脊髓背角pCREB-IR神经细胞数量少于CCI2w组（P〈0．05或0．01）。结论 CCI致慢性神经病理性疼痛大鼠背根神经节和脊髓背角pCREB表达增加，这可能是外周神经损伤后中枢和外周敏感化的分子机制。     

鞘内注射氯胺酮对神经病理性痛大鼠吗啡耐受时脊髓背角突触重塑的影响

目的 探讨鞘内注射氯胺酮对神经病理性痛大鼠吗啡耐受时脊髓背角突触重塑的影响.方法 鞘内置管成功的雄性SD大鼠48只,体重200～250 g,采用随机数字表法,将大鼠随机分为6组(n=8),置管后5 d,神经病理性痛组(NP组)、生理盐水对照组(NS组)、吗啡组(M组)、氯胺酮组(K组)和吗啡+氯胺酮组(MK组)采用背根神经节慢性压迫法制备神经病理性痛模型,假手术组(S组)仅暴露L5椎间孔.背根神经节慢性压迫后1 d NS组鞘内注射0.9%生理盐水20止,M组和K组分别给予吗啡20μg或氯胺酮50μg,MK组给予吗啡20μg+氯胺酮50μg,1次/d,连续14 d.分别于给药前(基础状态)、给药1、3、5、7、9、11、14 d时测定机械缩足阈值(PWT)和热缩足潜伏期(PWL).最后1d给药后立即处死大鼠,取脊髓组织,其中4只采用免疫组织化学方法测定脊髓背角突触数目,另外4只用于测定脊髓背角突触后膜致密物厚度.结果 与S组比较,其余5组PWT降低,PWL缩短,NP组、NS组、M组和K组突触数目和突触后膜致密物厚度增加(P＜0.05);与NP组比较,M组、K组和MK组PWT升高,PWL延长,突触数目和突触后膜致密物厚度降低(P＜0.05);与M组比较,MK组PWT升高,PWL延长,突触数目和突触后膜致密物厚度降低(P＜0.05).结论 鞘内注射氯胺酮可抑制神经病理性痛大鼠吗啡耐受时脊髓背角突触重塑.

Abstract：

Objective To investigate the effects of intrathecal (IT) ketamine on the synapsis remodeling in the spinal dorsal horn during devolopment of morphine tolerance in a rat model of neuropathic pain (NP). Methods Male SD rats weighing 200-250 g were used in this study. IT catheter was placed in the subarachnoid space according to Yaksh. Forty-eight SD rats in which IT catheter was successfully placed were randomly divided into 6groups (n=8 each): group sham operation (group S); group NP; group normal saline 20 μl IT(group NS);group morphine 20 μg IT (group M); group ketamine 50 μg IT (group K) and group morphine 20 μ g + ketamine 50 μg IT (group MK). NP was induced by compression of right L4,5 dorsal root ganglions with steel wire inserted through L4,5 intervertebral foramen in NP,M,K and MK groups. Normal saline or morphine and/or ketamine were injected IT once a day for consecutive 14 days. Paw withdrawal threshold (PWT) to mechanical stimulation and paw withdrawal latency (PWL) to a thermal nociceptive stimulus were measured on 0, 1, 3, 5, 7, 9, 11, 14 days during the consecutive 14 days of administration. The animals were sacrificed after the final IT administration. The lumbar segment of the spinal cord was removed for determination of the number of synapsis in the spinal dorsal horn by immuno-histochemistry in 4 animals in each group and observation of synaptic structure remodeling using electron microscope in another 4 animals in each group. Results Compared with group S, PWT was significantly decreased and PWL was shortened in the other 5 groups, and the number of synapsis was significantly increased and the synaptic structure was thickened in NP, NS, M and K groups (P ＜ 0.05). Compared with group NP,PWT was significantly increased and PWL was prolonged in M, K and MK groups, and the number of synapsis was significantly decreased and the thickness of synaptic structure was significantly reduced in group MK ( P ＜ 0.05).Compared with group M, PWT was significantly increased, PWL was prolonged, the number of synapsis was significantly decreased and the thickness of synaptic structure was significantly reduced in group MK ( P ＜ 0.05). Conclusion IT ketamine can inhibit the synaptic remodeling in the spinal dorsal horn during development of morphine tolerance in a rat model of NP.     

鞘内注射PSD-93反义寡核苷酸对神经病理性痛大鼠脊髓nNOS的影响

目的 探讨鞘内注射PSD-93反义寡核苷酸对神经病理性痛大鼠脊髓神经型一氧化氮合酶(nNOS)的影响.方法 雄性SD大鼠32只,体重250～350 g,随机分为4组(n=8):假手术+生理盐水组(C组);C7脊神经压迫+生理盐水组(N组);C7脊神经压迫+PSD-93误义寡核苷酸10μg组(M组);C7脊神经压迫+PSD-93反义寡核苷酸10μg组(A组).N组、M组和A组采用60 g微血管夹压迫大鼠右侧C7脊神经15 min制备神经病理性痛模型,经枕骨大孔鞘内置管至颈膨大处.术毕当日开始给药,每日1次,连续4 d.于术前2 d(T0)、术后1、3、5和7 d(T1-4)时测定机械痛阈和热痛阈,术后7 d处死大鼠取C7段脊髓,免疫组化法检测神经压迫侧脊髓PSD-93蛋白和nNOS的表达.结果 与T0时比较,N组和M组各时点机械痛阈及热痛阈降低(P<0.05);与C组比较,N组和M组各时点机械痛阈及热痛阈降低,N组、M组和A组脊髓背角PSD-93蛋白和nNOS表达上调(P<0.05);与N组和M组比较,A组各时点机械痛阈及热痛阈升高,脊髓背角PSD-93蛋白和nNOS表达下调(P<0.05).结论 鞘内注射PSD-93反义寡核苷酸可抑制神经病理性痛大鼠脊髓nNOS表达,nNOS在神经病理性痛中的作用可能受PSD-93蛋白调节.     

鞘内注射布托啡诺混合氯胺酮对炎性痛大鼠脊髓背角cAMP-PKA-CREB信号转导通路的影响

目的 探讨鞘内注射布托啡诺混合氯胺酮对炎性痛大鼠脊髓背角环磷腺苷-蛋白激酶A-环磷腺苷反应元件结合蛋白(cAMP-PKA-CREB)信号转导通路的影响.方法 雄性SD大鼠,体重240～280 g,取鞘内置管成功的大鼠24只,随机分为4组(n=6):炎性痛组(IP组)、布托啡诺组(B组)、氯胺酮组(K组)和布托啡诺+氯胺酮组(BK组).置管后5 d,于大鼠左后足掌面皮下注射5%甲醛50μl,以制备炎性痛模型.IP组、B组、K组和BK组于皮下注射甲醛前30 min分别鞘内注射生理盐水10 μl、布托啡诺12.5 μg、氯胺酮50μg、布托啡诺12.5μg混合氯胺酮50μg.注射甲醛后1 h内,每5 min观察大鼠痛行为学,并计算痛加权评分(PIS评分);于注射甲醛后2 h时处死大鼠,取L5脊髓组织,采用免疫组化法测定脊髓背角PKA和磷酸化CREB(p-CREB)的表达水平,并行免疫组化染色分级.结果 大鼠注射甲醛后均表现出典型的痛双相期,即急性痛时相(第1时相)和继发性痛时相(第2时相).与IP组比较,BK组第1、2时相PIS评分降低,大鼠脊髓背角PKA、p-CREB表达下调,免疫组化染色分级降低(P<0.05或0.01),B组、K组上述指标差异无统计学意义(P>0.05).结论 鞘内注射布托啡诺混合氯胺酮可减轻大鼠炎性痛,其机制可能与抑制脊髓背角cAMP-PKA-CREB信号转导通路有关.     

神经病理性痛大鼠背根神经节和脊髓背角Nogo-A蛋白表达的变化

目的 评价神经病理性痛大鼠背根神经节和脊髓背角Nogo-A蛋白表达的变化.方法 健康成年雄性SD大鼠72只,体重250～300 g,采用随机数字表法,将大鼠随机分为3组(n=24):对照组(C组)、假手术组(S组)和神经病理性痛组(NP组).C组不做任何处理,NP组采用结扎并剪断胫神经和腓总神经的方法制备大鼠神经病理性痛模型,S组仅切皮暴露坐骨神经但不结扎和剪断神经.于结扎后1、7、14、21 d时采用yon Frey丝测定大鼠机械痛阈.于各时点随机取6只大鼠处死后取损伤侧L5背根神经节和L4,5脊髓,采用免疫荧光标记法测定Nogo-A蛋白的表达(n=3),采用Westernblot法测定Nogo-A蛋白的表达(n=3).结果 与C组和S组比较,NP组大鼠结扎后7、14、21 d时机械痛阈降低,结扎后7、14 d时背根神经节Nogo-A蛋白表达下调,结扎后14、21 d时脊髓背角Nogo-A蛋白表达上调(P＜0.05).结论 背根神经节及脊髓背角Nogo-A蛋白可能在外周神经损伤诱发大鼠神经病理性痛过程中发挥重要作用.

Abstract：

Objective To investigate the changes in the expression of Nogo-A protein in the dorsal root ganglion (DRG) and spinal dorsal horn in a rat model of neuropathic pain (NP) .Methods Seventy-two male SD rats weighing 250-300 g were randomly divided into 3 groups ( n = 24 each) : control group (group C) , sham operation group (group S) and NP group. NP was induced by ligation and severance of tibial and common fibular nerves according to the technique described by Isabelle et al. The mechanical withdrawal threshold (MWT) to von Frey filament stimulation was measured at 1, 7, 14 and 21 days after ligation. Six rats in each group were randomly selected at each time point and sacrificed (3 for determination of Nogo-A protein expression by immunofluorescence, 3 for determination of Nogo-A protein expression by Western blot) . The L5 DRG and L4,5 segment of spinal cord on the injured side were removed for determination of Nogo-A protein expression by immunofluorescence and Western blot. Results Compared with the groups C and S, MWT was significantly decreased at 7, 14 and 21 days after ligation, the expression of Nogo-A protein in the DRG was down-regulated at 7 and 14 days after ligation and the expression of Nogo-A protein in the spinal dorsal horn was up-regulated at 14 and 21 days after ligation ( P ＜0.05) .Conclusion The Nogo-A protein in the DRG and spinal dorsal horn may play an important role in peripheral nerve injury-induced NP in rats.     

鞘内注射舒芬太尼对神经病理性痛大鼠脊髓背角NMDA受体及CGRP表达的影响

目的 评价鞘内注射舒芬太尼对神经病理性痛大鼠脊髓背角N-甲基-D-天冬氨酸(NMDA)受体及降钙素相关基因肽(CGRP)表达的影响.方法 雄性SD大鼠36只,体重220～280 g,随机分为4组(n=9):正常对照组(C组)、假手术组(S组)、坐骨神经分支选择性损伤组(SNI组)和舒芬太尼+坐骨神经分支选择性损伤组(S+SNI组).SNI组和S+SNI组制备SNI模型,S+SNI组在SNI术后14 d内每天鞘内注射舒芬太尼1 μg(用生理盐水稀释至10 μl),其余各组给予等容量生理盐水.于SNI给药前2 d(基础状态)及给药1、2、7、14 d测定机械痛阈和热缩足潜伏期,分别于给药2、7、14 d测定痛阈后立即处死3只大鼠,采用免疫组化法测定L5节段脊髓背角NMDA受体和CGRP表达水平.结果 与C组和S组比较,SNI组机械痛阚降低,NMDA受体和CGRP表达上调(P<0.01),热缩足潜伏期差异无统计学意义(P>0.05).与SNI组比较,S+SNI组机械痛阈升高,热缩足潜伏期延长,NMDA受体和CGRP表达下调(P<0.01).结论 鞘内注射舒芬太尼可抑制脊髓背角NMDA受体和CGRP表达上调,从而减轻大鼠神经病理性痛.     

鞘内预注射L-NAME对神经性疼痛大鼠脊髓背角降钙素基因相关肽表达的影响

目的 观察鞘内预注射NG-硝基-L-精氨酸-甲基酯(L-NAME)对结扎坐骨神经所致神经性疼痛大鼠脊髓背角降钙素基因相关肽(CGRP)表达的影响。方法 选择鞘内置管后无神经损伤症状的SD雌性大鼠96只,随机分为4组,每组24只。A组:假手术组;B组:坐骨神经结扎组;C组:假手术前15 min鞘内注射L-NAME 10 μl(250 μg);D组:坐骨神经结扎前15 min鞘内注射L-NAME 10 μl(250 μg)。各组分别在术后第1、4、7和14天随机处死6只大鼠。采用免疫组织化学方法观察各组大鼠结扎侧脊髓背角CGRP的表达。结果 与A组比较,B组、D组大鼠结扎侧脊髓背角CGRP表达在术后第4、7和14天明显升高(P<0.05),C组差异无显著性。与C组比较,D组大鼠结扎侧脊髓背角CGRP表达在术后第4、7和14天明显升高(P<0.05)。而D组大鼠结扎侧脊髓背角内的CGRP表达与B组比较,差异无显著性(P>0.05)。结论 鞘内预注射L-NAME不能抑制周围神经损伤所诱导的脊髓背角CGRP表达,提示一氧化氮介导神经性疼痛的作用不是通过促进CGRP释放实现的。     

鞘内吗啡对切口疼痛模型大鼠脊髓背角P物质的影响

目的研究鞘内(IT)吗啡对切口疼痛模型大鼠脊髓背角P物质(SP)的影响.方法雄性SD大鼠16只,随机分为四组(每组4只)假手术组(组Ⅰ)、术前30min IT 0.9%氯化钠20μl组(对照组,组Ⅱ)、术后30min IT吗啡5μg组(组Ⅲ)和术前30min IT吗啡5μg组(组Ⅳ).按Brennan法制成切口疼痛模型,以累积疼痛评分确定疼痛行为.免疫组织化学方法观察脊髓背角SP免疫反应(SP-LI).结果组Ⅲ和组Ⅳ大鼠的累积疼痛评分均明显低于组Ⅱ(P＜0.01).组Ⅱ大鼠术侧脊髓背角浅层SP-LI物质积分光密度明显高于组Ⅰ及对侧(对照组0.62±0.07,假手术组0.40±0.09,P＜0.01);与组Ⅱ比较,组Ⅳ的大鼠术侧脊髓背角浅层SP-LI物质积分光密度(0.37±0.06)明显降低(P＜0.01),但两用药组间比较无显著差别.结论在大鼠切口疼痛模型中,术前IT吗啡的抗伤害作用与其抑制SP在脊髓背角的释放有关.