胍丁胺鞘内注射对骨癌痛大鼠痛行为及脊髓CXCL13表达的影响

Effects of agmatine intrathecal injection on pain behavior and spinal cord CXCL13 in bone cancer pain rats

目的探讨胍丁胺鞘内注射对骨癌痛大鼠痛行为及脊髓趋化因子CXC配体13(CXCL13)表达的影响。方法成年雌性SD大鼠60只,体质量200~220 g,采用随机数字表法分为3组:假手术组(A组)、骨癌痛组(B组)、骨癌痛+胍丁胺组(C组),各20只。B、C组采用大鼠胫骨上端骨髓腔内注入Walker 256癌细胞的方法建立骨癌痛模型,A组胫骨髓腔内注射等量生理盐水,B、C两组鞘内置管。造模成功后,C组鞘内注射胍丁胺160 mg/kg,连续6天;B组鞘内给予等量生理盐水,连续6天;A组不作处理。于造模后第12天用von Frey丝测定3组大鼠机械缩足反射阈值(MWT);痛阈测定结束后,麻醉处死大鼠,取脊髓组织,采用免疫荧光法检测CXCL13在神经元中的表达;采用Western blot法分析CXCL13蛋白表达及逆转录-聚合酶链反应(RT-PCR)法检测CXCLl3 mRNA的表达。结果建模后12天,与A组比较,B、C组大鼠MWT明显低于A组,与B组比较,C组MWT高于B组,差异均有统计学意义(P<0.05)。建模后12天,与A组比较,B、C组大鼠CXCL13在脊髓背角神经元中表达增加,CXCL13蛋白及其mRNA表达明显增加(P<0.05);与B组比较,C组大鼠CXCL13在脊髓背角神经元中表达降低,CXCL13蛋白及其mRNA表达明显减少(P<0.05)。结论鞘内注射胍丁胺可有效改善大鼠骨癌痛痛觉过敏行为,其机制可能与抑制大鼠脊髓CXCL13表达有关。

Objective To investigate the effect of agmatine intrathecal injection on pain behavior and expression of CXC ligand 13(CXCL13)of spinal chemokines in rats with bone cancer pain.Methods Adult female SD rats weighing 200~220 g were randomly divided into three groups(n=20):sham operation group(group A),bone cancer pain(group B)and bone cancer pain+agmatine(group C).Group B and C adopted the upper tibia bone marrow cavity of rats injected Walker 256 cancer method to establish model of bone cancer pain,Group A received intramedullary injection of the same amount of normal saline,meanwhile group B and C received intrathecal sheath tubes.After successful molding,group C received intrathecal injection of agmatine 160 mg/kg for six consecutive days,group B was given intrathecal injection of normal salinein equalamount for six consecutive days,while group A was not treated.On 12th day after modeling,mechanical foot shrinkage reflex threshold(MWT)was measured by von Frey silk.After the pain threshold was determined,the rats were anesthetized and sacrificed,the spinal cord tissues were harvested,and the expression of CXCL13 in neurons was detected by immunofluorescence method.CXCL13 protein expression was assessed by Western blot and the expression of CXCLl3 mRNA was detected by reverse transcription-polymerase chain reaction(RT-PCR).Results MWT of rats in group B and C was significantly lower than that in group A(P<0.05).MWT of group C was significantly higher than that of group B 12 days after modeling(P<0.05).The expression of CXCL13 in neurons of rats in group B and C inc reased 12 days after modeling,and the CXCL13 protein content and mRNA expression were significantly up-regulated(P<0.05).The expression of CXCL13 in neurons in group C decreased 12 days after modeling,and the content of CXCL13 protein and mRNA expression significantly decreased(P<0.05).Conclusions Agmatine intrathecal injection can effectively improve the hypersensitivity of pain and pain in bone cancer in rats.The mechanism may be related to the inhibition of CXCL13 expression in spinal cord of rats.