大鼠鞘内注射MCP-1中和抗体缓解骨癌痛

目的观察脊髓趋化因子单核细胞趋化蛋白-1(monocyte chemotactic protein-1,MCP-1,或CCL2)在骨癌痛大鼠中的可能作用。方法大鼠胫骨骨髓腔接种Walker256肿瘤细胞建立骨癌痛模型。观测造模前、后大鼠机械性痛觉超敏Von Frey阈值并观察造模后d 10～12,鞘内给予MCP-1中和抗体对大鼠Von Frey阈值和脊髓小胶质细胞激活标志物(ox-42)表达的影响。结果大鼠种瘤后6～12 d,机械性痛觉超敏Von Frey阈值进行性下降(P<0.01);与对照组相比,鞘内给予MCP-1中和抗体后,脊髓ox-42的表达水平明显降低(P<0.01),Von Frey阈值的明显升高(P<0.01)。结论大鼠鞘内注射MCP-1中和抗体缓解骨癌痛,其机制可能与抑制小胶质细胞的激活相关。     

鞘内注射TDAG8的siRNA对大鼠骨癌痛的缓解作用

目的观察鞘内注射T细胞死亡相关基因8(T celldeath-associated gene 8,TDAG8)的小干扰RNA(small inter-fering RNA,siRNA)对骨癌痛大鼠机械性痛觉过敏以及脊髓TDAG8表达的影响。方法通过将Walker256肿瘤细胞接种在大鼠左侧胫骨骨髓腔内建立骨癌痛模型。观察接种肿瘤前后大鼠机械缩爪反射阈值(paw withdrawl threshould,PWT)和脊髓TDAG8表达水平的变化;并进一步观察痛觉过敏形成后鞘内注射TDAG8的siRNA对大鼠PWT和脊髓TDAG8表达的影响。结果大鼠接种肿瘤后6～18 d,PWT明显下降(P<0.01),脊髓TDAG8的表达明显升高(P<0.01);与对照组相比,鞘内注射siRNA的骨癌痛大鼠,其PWT明显增高(P<0.05),脊髓TDAG8表达水平明显降低(P<0.01)。结论脊髓部位的TDAG8可能参与了大鼠骨癌痛的形成和发展,鞘内注射其siRNA可以通过干扰脊髓TDAG8的表达而具有疼痛缓解作用。     

鞘内注射氟代柠檬酸对炎性痛敏大鼠的镇痛作用

目的研究鞘内注射氟代柠檬酸(fluorocitrate,Fc)对致炎大鼠痛觉过敏的影响。方法采用大鼠右后爪踝关节外侧皮下注射完全弗氏佐剂(complete freunds adjuvant,CFA)50μl致炎模型。测定给予CFA或Fc前后大鼠机械性缩爪阈值(MWT)和热刺激缩爪潜伏期(TWL)。免疫组化分析脊髓背角星形胶质细胞标记物(GFAP)和小胶质细胞标记物(OX-42)的表达。结果大鼠皮下注射CFA24h后出现明显的炎性痛敏,鞘内注射Fc后4,6,8,10,12h,与CFA组大鼠比较,大鼠MWT明显提高(P<0.01),TWL明显延长(P<0.01)。鞘内注射Fc6h后,降低脊髓背角GFAP和OX-42表达。结论脊髓胶质细胞可能参与炎性痛敏的发生和维持,氟代柠檬酸可能通过抑制其生物活性而发挥镇痛作用。     

骨癌痛大鼠鞘内注射U0126的抗痛觉过敏作用

目的研究鞘内注射(it)U0126对骨癌痛大鼠机械痛敏的影响和对脊髓背角磷酸化cAMP反应元件结合蛋白(pCREB)表达的影响,探讨ERK-CREB信号转导通路在骨癌痛中的作用。方法①40只成年♀SD大鼠分为5组,假模型组Ⅰ和骨癌痛模型组Ⅱ、Ⅲ、Ⅳ、Ⅴ。建模后d 10每只大鼠分别it 10μg U0126、5%二甲亚砜10μl和U0126 0.1、1、10μg(U0126溶于10μl 5%二甲亚砜中),测机械性缩爪阈值(MWT)和双下肢负重差(WBD);②25只成年♀SD大鼠分为5组,T1、T2和T3组在制作骨癌痛模型后d 10,itU0126 10μg后1、6、24 h处死大鼠,M组为模型对照组,it5%二甲亚砜10μl后6 h处死大鼠,S组为空白对照组。免疫组化方法测定L4-6术侧脊髓背角pCREB免疫反应阳性神经元数量。结果鞘内注射U0126 1μg和10μg明显逆转了骨癌痛引起的机械痛敏;鞘内注射10μg U0126明显减少脊髓背角pCREB表达,且效果至少可持续6 h。结论 ERK-CREB通路可能参与骨癌痛。     

鞘内注射LY294002缓解大鼠骨癌痛

目的观察鞘内注射(intrathecal injection,i.t.)磷脂酰肌醇3-激酶(PI3K)抑制剂LY294002对骨癌痛大鼠疼痛行为学、脊髓背角磷酸化Akt(p-Akt)表达的影响。方法♀SD大鼠40只,体质量180~200 g,随机分为5组(n=8):假手术组(Ⅰ组)、假手术+LY294002组(Ⅱ组)、骨癌痛组(Ⅲ组)、骨癌痛+二甲基亚砜(DMSO)组(IV组)、骨癌痛+LY294002(V组),于大鼠左侧胫骨干骺端骨髓腔内注射Walker256乳腺癌细胞构建胫骨癌痛模型。术后d 7~9鞘内连续注射浓度为2.5 g·L-1的LY294002 10μL或10μL的5%DMSO。观测术前及术后d 7给药后每小时机械痛阈(至8 h)。术后d 9处死大鼠,取各组大鼠的L4~6脊髓组织进行免疫组化染色,检测脊髓背角PI3K活化标志p-Akt的表达。结果骨癌痛组大鼠(Ⅲ、Ⅳ、Ⅴ组)机械痛阈(MWT)明显低于假手术组(Ⅰ组)(P<0.01),V组在给药后2~4h痛阈明显升高(P<0.05),3 h达到峰值(P<0.01)。与Ⅰ组比较,Ⅲ、Ⅳ组脊髓背角p-Akt阳性细胞数明显增加,p-Akt表达增多(P<0.01)。与Ⅲ、Ⅳ组比较,Ⅴ组鞘内注射LY294002后能明显降低脊髓背角p-Akt的表达(P<0.05)。结论 PI3K/Akt通路可能参与大鼠骨癌痛的发生。     

趋化因子受体CCR2拮抗剂在大鼠骨癌痛治疗中的可能机制

目的观察脊髓单核细胞趋化蛋白受体CCR2在大鼠骨癌痛形成过程中的可能机制。方法大鼠左侧胫骨骨髓腔内接种Walker256乳腺癌细胞制备骨癌痛模型。观察并测量各组大鼠术前1 d,术后3、6、9、10、11、12 d的机械痛阈值。术后12 d取材,免疫组织化学法检测脊髓背角星形胶质细胞标志物(GFAP)的平均光密度值(MOD),观察脊髓小胶质细胞增殖活化情况。结果与对照组相比,鞘内给予CCR2拮抗剂后大鼠机械痛阈值明显升高,脊髓GFAP表达明显降低(P<0.01)。结论鞘内注射CCR2特异性拮抗剂可能通过抑制脊髓星形胶质细胞的活化而缓解大鼠骨癌痛,CCR2可能是治疗骨癌痛新的靶点。     

鞘内注射左旋布比卡因下调甲醛炎性痛大鼠远位触液神经元P物质的表达

目的观察鞘内注射左旋布比卡因对甲醛炎性痛大鼠P物质(substanceP,SP)在脊髓背角及远位触液神经元(thedistal cerebrospinal fluid contacting neuron,dCSF-CN)表达的影响。方法采用CB-HRP大鼠侧脑室注射示踪标记dCSF-CN;48h后先鞘内注射0.5%左旋布比卡因10μl(并以鞘内注射10μl人工脑脊液作对照),大鼠左后掌足跖部皮下注射2.5%福尔马林建立炎性痛模型,记录大鼠舔足时间,1h后测定机械缩足阈值(mechanical withdrawal threshold,MWT)评估机械痛敏;免疫组织化学光镜镜检及免疫电镜镜检P物质在脊髓背角(L4~5)及dCSF-CN的表达。结果鞘内注射左旋布比卡因减少大鼠福尔马林试验的舔足时间(P<0.01),MWT值无变化(与基础值对比,P>0.05),SP在脊髓背角及dCSF-CN的表达弱于对照组(P<0.01)。结论鞘内注射左旋布比卡因减低脊髓伤害性疼痛反应及下调SP在dCSF-CN的表达。     

MCP-1中和抗体鞘内注射对骨癌痛吗啡耐受大鼠OX-42和炎症因子表达的作用

目的研究MCP-1中和抗体鞘内注射对骨癌痛吗啡耐受大鼠脊髓OX-42和炎症因子TNF-α、IL-1、IL-6表达的作用。方法应用Walker256肿瘤细胞胫骨骨髓腔注射和鞘内注射吗啡建立大鼠骨癌痛吗啡耐受动物模型,采用免疫组化、ELISA检测方法观察MCP-1中和抗体鞘内注射对骨癌痛吗啡耐受大鼠脊髓OX-42和炎症因子TNF-α、IL-1、IL-6表达的作用。结果 BM+Ab组大鼠MCP-1中和抗体鞘内注射后脊髓OX-42和炎症因子TNF-α、IL-1、IL-6表达显著减少。结论 MCP-1可能通过激活小胶质细胞(OX-42)引发炎症反应从而导致骨癌痛吗啡耐受。     

鞘内注射硫酸镁和吗啡对切口痛大鼠脊髓背角p-αCaMK Ⅱ表达的影响

目的观察鞘内注射(it)硫酸镁(MgSO4)和吗啡对切口痛大鼠脊髓背角磷酸化钙—钙调蛋白依赖性蛋白激酶Ⅱα(p-αCaMKⅡ)表达的影响。方法所有大鼠术前8d鞘内置管,用机械缩足反射阈值、热缩足潜伏期和累计疼痛评分来评价大鼠疼痛行为学变化;用免疫组织化学和Western blot法来测定吗啡和硫酸镁对大鼠脊髓背角p-αCaMKⅡ表达的影响。结果术前或术后30minit吗啡5μg或MgSO4188μg和吗啡2.5μg使术后2h的机械性缩爪阈值(MWT)和热刺激缩爪阈值(TWL)明显延长(P<0.01),累积疼痛评分明显降低(P<0.01);术前30minitMgSO4375μg或吗啡5μg或MgSO4188μg和吗啡2.5μg使大鼠术后2h脊髓背角p-αCaMKⅡ表达明显减少(P<0.05)。结论在大鼠切口痛模型中,it吗啡5μg或MgSO4188μg和吗啡2.5μg具有确切的抗伤害作用,其抗伤害作用可能与抑制脊髓背角p-αCaMKⅡ表达有关。     

Spinal nerve ligation reduces nitric oxide synthase activity and expression: Effect of resveratrol

The effect of resveratrol on activity and expression of nitric oxide synthase (NOS) in the spinal cord of neuropathic rats was assessed. Spinal nerve ligation produced tactile allodynia along with a reduction of catalytic activity of the constitutive Ca²⁺-dependent NOS (eNOS and nNOS isoforms) in the ipsilateral dorsal horn, but not contralateral dorsal or ipsilateral or contralateral ventral, spinal cord at 1, 5, 10 and 15 days after surgery compared to naïve and sham-operated animals. Nerve ligation also induced a reduction of nNOS expression in the ipsilateral dorsal horn spinal cord at 10 and 15 days after surgery. Intrathecal resveratrol reduced allodynia and reversed the reduction of constitutive Ca²⁺-dependent NOS activity in the ipsilateral dorsal spinal cord. Moreover, resveratrol significantly reversed the reduction of nNOS expression in the ipsilateral dorsal horn spinal cord. Results show that spinal nerve ligation leads to development of tactile allodynia along with a reduction in constitutive Ca²⁺-dependent NOS activity and nNOS isoform expression in the ipsilateral dorsal horn. Data suggest that resveratrol may reduce tactile allodynia in neuropathic rats by restoring altered NOS activity and expression.     

Spinal nerve ligation reduces nitric oxide synthase activity and expression: effect of resveratrol

The effect of resveratrol on activity and expression of nitric oxide synthase (NOS) in the spinal cord of neuropathic rats was assessed. Spinal nerve ligation produced tactile allodynia along with a reduction of catalytic activity of the constitutive Ca²⁺-dependent NOS (eNOS and nNOS isoforms) in the ipsilateral dorsal horn, but not contralateral dorsal or ipsilateral or contralateral ventral, spinal cord at 1, 5, 10 and 15 days after surgery compared to naïve and sham-operated animals. Nerve ligation also induced a reduction of nNOS expression in the ipsilateral dorsal horn spinal cord at 10 and 15 days after surgery. Intrathecal resveratrol reduced allodynia and reversed the reduction of constitutive Ca²⁺-dependent NOS activity in the ipsilateral dorsal spinal cord. Moreover, resveratrol significantly reversed the reduction of nNOS expression in the ipsilateral dorsal horn spinal cord. Results show that spinal nerve ligation leads to development of tactile allodynia along with a reduction in constitutive Ca²⁺-dependent NOS activity and nNOS isoform expression in the ipsilateral dorsal horn. Data suggest that resveratrol may reduce tactile allodynia in neuropathic rats by restoring altered NOS activity and expression.     

ATP- and adenosine-mediated signaling in the central nervous system: chronic pain and microglia: involvement of the ATP receptor P2X4

We have been studying the role of ATP receptors in pain and already reported that activation of P2X(2/3) heteromeric channel/receptor in primary sensory neurons causes acutely tactile allodynia, one hallmark of neuropathic pain. We report here that tactile allodynia under the chronic pain state requires an activation of the P2X(4) ionotropic ATP receptor and p38 mitogen-activated protein kinase (MAPK) in spinal cord microglia. Two weeks after L5 spinal nerve injury, rats displayed a marked mechanical allodynia. In the rats, activated microglia were detected in the injured side of the dorsal horn and the level of the dually-phosphorylated active form of p38MAPK (phospho-p38MAPK) in these microglia was increased. Moreover, intraspinal administration of a p38MAPK inhibitor, SB203580, suppressed the allodynia. We also found that the expression level of P2X(4) was increased strikingly in spinal cord microgila after nerve injury and that pharmacological blockade or inhibition of the expression of P2X(4) reversed the allodynia. Taken together, our results demonstrate that activation of P2X(4) or p38MAPK in spinal cord microglia is necessary for tactile allodynia after nerve injury.     

运动训练对脊髓损伤大鼠脊髓内BDNF及其受体TrkB表达的影响

目的 研究运动训练对脊髓损伤（SCI）大鼠脊髓内脑源性神经营养因子（BDNF）及其酪氨酸激酶受体B（TrkB）表达的影响,探讨运动训练促进脊髓损伤功能恢复的可能机制。方法 24只成年雌性SD大鼠随机分为假手术组、损伤对照组和运动训练组。采用通用型脊髓打击器建立大鼠T10脊髓损伤模型。损伤后7天起,对SCI大鼠进行4周运动训练,假手术组和损伤对照组不进行运动训练。损伤前及损伤后第1、2、3、4、5周采用BBB评分评定运动功能。运动训练结束后(即损伤后5周)取大鼠T12～L1节段脊髓,免疫组织化学检测脊髓内BDNF和TrkB表达及分布,Western blot检测脊髓内BDNF和TrkB蛋白含量。结果 运动训练组和损伤对照组BBB评分均较损伤后第1、2周明显提高,运动训练组较损伤对照组增加更为显著（P<0.05）。BDNF免疫反应阳性产物多分布于脊髓前角,脊髓后角及中央管周围也有出现;运动训练组BDNF阳性染色颗粒增多,平均光密度值较假手术组及损伤对照组均显著增加（P<0.05）。TrkB免疫反应阳性产物于脊髓前角、后角、中央管周围等处均出现较多分布;运动训练组TrkB阳性染色颗粒增多,平均光密度值较假手术组及损伤对照组均显著增加（P<0.05）。Western blot结果显示运动训练组大鼠脊髓内BDNF及TrkB的表达较假手术组、损伤对照组均明显增加(P＜0.05)。结论 运动训练能诱导脊髓损伤大鼠脊髓内BDNF及其受体TrkB表达,促进SCI大鼠运动功能恢复。     

脊髓p38MAPK在大鼠背根节慢性压迫神经病理性疼痛中的作用

目的观察背根节慢性压迫(chronic compression of dorsal root ganglion,CCD)痛大鼠脊髓p-p38MAPK表达的变化,探讨p38MAPK与慢性神经病理性痛的相关性。方法♂SD大鼠36只,随机分为正常组(Naive组,n=4)、假手术组(Sham组,n=16)和背根节慢性压迫组(CCD组,n=16),Sham组和CCD组又分别分为5,7,14d和21d4个亚组(n=4),分别用免疫印迹法(Westernblot)检测各组大鼠脊髓磷酸化p38丝裂原活化蛋白激酶(p-p38MAPK)表达的变化。结果3组大鼠脊髓均见p-p38MAPK蛋白表达。Naive组和Sham组间比较差异无统计学意义。CCD组大鼠脊髓p-p38MAPK蛋白表达较Naive组和Sham组明显增多;与Sham组相比,CCD后5,7,14,21d各组大鼠脊髓背角神经元胞质p-p38MAPK蛋白分别增加了138·1%(P<0·01)、184·3%(P<0·01)、247·4%(P<0·01)和90·4%(P<0·05)。胞核p-p38MAPK蛋白分别增加了167·3%(P<0·01)、177·8%(P<0·01)、262·7%(P<0·01)和72·7%(P<0·05)。结论在CCD大鼠模型中,脊髓p38MAPK的活化与背根节慢性压迫致神经病理性痛的形成和发展存在密切联系。     

Pre-emptive intrathecal quinidine alleviates spinal nerve ligation-induced peripheral neuropathic pain

Objectives Quinidine, a class I anti‐arrhythmic agent, is a sodium channel blocker that is more potent than lidocaine and mexiletine. This study tested pre‐emptive intrathecal quinidine to attenuate neuropathic pain induced by lumbar spinal nerve ligation (SNL). Methods Ninety‐six adult male Sprague–Dawley rats were grouped equally (n = 24 per group) as follows: group S (sham), removal of transverse process only; group L, SNL; group Q₃₅, SNL pretreated with intrathecal quinidine 35 mm (50 µl); group Q₇₀, SNL pretreated with intrathecal quinidine 70 mm (50 µl). Neuropathic pain was measured by thermal hyperalgesia and mechanical allodynia. Other measurements included dys‐regulation of sodium channel Nav_1.3 in dorsal root ganglion (DRG) and spinal microglia activation in spinal dorsal horn. Key findings Spinal nerve ligation induced abnormal mechanical allodynia and thermal hyperalgesia, up‐regulated Nav_1.3 in DRG, and activated microglia in spinal cord. Group Q₇₀ showed attenuated thermal hyperalgesia (P < 0.001) and mechanical allodynia (P < 0.05) on postoperative day 5 (POD₅) but not on POD₇, reversed up‐regulated expression of Nav_1.3 on POD₃ and POD₇ in DRG and significantly attenuated microglia activation on POD₇ (P = 0.032) in spinal cord. Conclusions Pretreatment with intrathecal quinidine 70 mm before SNL attenuates nerve ligation‐induced neuropathic pain. The duration of the effect is 5 days.