|
摘要：
目的 探讨脊髓水平细胞外信号调节激酶（extracellular regulated kinase , ERK）的活化在大鼠骨癌痛发生中的作用。方法 实验一：雌性SD大鼠48只，体重160 g~200 g，按随机数字表法分成2组（每组24只），A组（对照组）、B组（模型组）。采用胫骨上段骨髓腔接种Walker-256乳腺癌细胞方法制备大鼠骨癌痛模型。于术前1 d、术后1、3、5、7、10、14、21 d测定大鼠机械刺激缩足反射阈值( mechanical withdrawal threshold, MWT )和自由行走痛行为学评分（ambulatory-evoked pain scores, APS），术后第7、14、21天取大鼠腰段脊髓，采用Western blot方法检测脊髓磷酸化细胞外信号调节激酶1/2（phosphorylated ERK1/2, p-ERK1/2）的表达。实验二： 60只大鼠按随机数字表法为5组（每组12只）：S组、N1组、N2组、N3组和N4组。假手术组+ 生理盐水(S组)、骨癌痛+ 生理盐水（N1组）、骨癌痛+ NO-711 10 μg（N2组）、骨癌痛+ NO-711 20 μg（N3组）、骨癌痛+ NO-711 40 μg（N4组）。于术后第14天鞘内分别给予生理盐水（S组、N1组）、γ-氨基丁酸转运体抑制剂NO-711 10 μg（N2组）、 NO-711 20 μg（N3组）、 NO-711 40 μg（N4组）。最后一次给药后0.5、1、2、4、8、12、24 h观察大鼠MWT和APS，于给药后4 h取腰段脊髓，采用Western blot方法检测脊髓p-ERK1/2的表达。结果 实验一：与A组和手术前比，从术后第7天开始，B组MWT(8.02±0.30)显著降低(P<0.01)，APS(0.88±0.22)和p-ERK1/2表达显著升高(P＜0.01)。实验二：与给药前相比，N1组大鼠MWT和APS在鞘内给予NS后无明显改变。与给药前和N1组相比，NO-711可显著提高骨癌痛大鼠MWT（P＜0.05），其作用时间可分别达8 h（N2组, 6.49±0.64）和12 h（N3组12.40±1.37、N4组11.48±0.69），但不能改善骨癌痛大鼠APS。Western blot：与S组相比，N1组p-ERK1/2表达明显上调（P＜0.01）；与N1组相比，N2、N3、N4组p-ERK1/2表达含量降低（P＜0.01）。结论 脊髓背角p-ERK1/2表达上调参与了骨癌痛的产生，NO-711通过抑制p-ERK表达上调缓解骨癌痛大鼠机械痛觉过敏。
|
|
Abstract: Objective To explore the role of extracellular signal-regulated kinase (ERK) activation in the lumbar spinal cord induced by the tibial cancer pain in rats. Methods PartⅠ： Forty-eight SD female rats (160g-200g) were randomly divided into two groups (n=24). Group A (control group): intra-tibial injection of 5 μl saline. Group B (model group): intra-tibial injection of 5 μl Walker-256 mammary gland carcinoma cells of rats (1×105/μl).Mechanical withdrawl threshold (MWT) of mechanical stimulus and ambulatory-evoked pain scores were recorded one day before operation and on 1, 3, 5, 7, 10, 14, 21 d after operation respectively. Expressionof phosphorylated ERK1/2 (p-ERK1/2) were detected on 7, 14, 21d after operation respectively. PartⅡ： Sixty female Sprague-Dawley rats (160 g-200 g) were randomly divided into five groups (n=12):sham +NS group (group S) ;bone cancer pain+NS（group N1）;bone cancer pain +NO-711 10 μg（group N2）;bone cancer pain+ NO-711 20 μg（group N3）;bone cancer pain+ NO-711 40 μg（group N4）. On the 14th day after intra-tibial injection of 5 μl Walker-256 mammary gland carcinoma cells (post-treatment) NO-711 or normal saline were intrathecally administered thrice (once a day). MWT of mechanical stimulus and ambulatory-evoked pain scores were recorded at the time of 30 min, 1, 2, 4, 8, 12, 24 h after last injection. Test the p-ERK1/2 expression in the spinal cord by western blot analysis at 4 hours after last injection. Results PartⅠ: From the 7th day after operation, there were great significance differences at MWT8.02±0.30、ambulatory-evoked pain scores(0.88±0.22) and the expression of p-ERK1/2 compared with pre-operation in group B. MWT were significantly decreased while ambulatory-evoked pain scores and the expression of p-ERK1/2 were significanty increased in group B as compared to group A from the 7th day post-operation. PartⅡ: After and before i.t. administration in group N1 the MWT and scores of ambulatory-evoked pain showed no statistical significance. Received with Intrathecal post-treatment with NO-711 inhibited allodynia in rats with bone cancer pain, but could not relieve ambulatory-evoked pain. The inhibitory effect lasted for 8 h（group N2, 6.49±0.64）and 12 h（group N3 12.40±1.37、N4 11.48±0.69）respectively. Compared with group S, Western blot analysis revealed that p-ERK1/2 expression in the spinal cord in group N1 was significantly increased （P＜0.05）; Compared with group N1, p-ERK1/2 expression in the spinal cord in group N2、N3、N4 were significantly decreased （P＜0.01）. Conclusion Our studies indicate that activation of ERK in the lumbar spinal cord is involved in the induction and maintenance of bone cancer pain in rats. Intrathecal injection of GAT-1 inhibitor attenuated mechanical hyperalgesia via inhibiting the up-regulation of p-ERK1/2 in rat tibial bone cancer pain model.
|
