脊髓JNK/MCP-1信号通路在大鼠骨癌痛维持中的作用

Role of JNK/MCP-1 signaling pathway in spinal cord in maintenance of bone cancer pain in rats

目的 评价脊髓c-Jun氨基末端激酶/单核细胞趋化蛋白-1（JNK/MCP-I）信号通路在大鼠骨癌痛维持中的作用.方法 清洁级成年雌性未交配SD大鼠50只,体重150 ～ 180 g,采用随机数字表法分为5组（n=10）：假手术组（S组）、假手术＋ JNK抑制剂SP600125（SP组）、骨癌痛组（BCP组）、骨癌痛＋ DMSO组（BCP＋ DMSO组）和骨癌痛＋SP600125组（BCP＋ SP组）.采用左侧胫骨骨髓腔内接种Walker256乳腺癌细胞的方法制备骨癌痛模型.SP组和BCP＋ SP组于模型制备后10-12 d时鞘内注射SP600125 10 μg（10μ1）,1次/d,BCP＋ DMSO组注射5％DMSO 10 μl,1次/d.模型制备前1d、制备后3、6、9、10、11和12d时测定机械痛阈.于模型制备后12 d时处死,取L4-6脊髓组织,采用免疫组化学法和Western blot法测定MCP-1的表达.结果 与S组比较,BCP组、BCP＋ DMSO组和BCP＋ SP组模型制备后6-12 d时机械痛阈降低,脊髓MCP-1表达上调（P＜0.01）,SP组上述指标差异无统计学意义（P＞0.05）;与BCP组比较,BCP＋ SP组模型制备后10-12 d时机械痛阈升高,脊髓MCP-1表达下调（P＜0.01）,BCP＋ DMSO组上述指标差异无统计学意义（P＞0.05）.结论 脊髓JNK/MCP-1信号通路可能参与了大鼠骨癌痛的维持.

Objective To evaluate the role of c-Jun N-terminal kinase （JNK）/monocyte chemoattractant protein-1 （MCP-1） signaling pathway in the spinal cord in the maintenance of bone cancer pain （BCP） in rats.Methods Fifty female Sprague-Dawley rats,weighing 150-180 g,were randomly divided into 5 groups （n =10 each） using a random number table：sham operation group （group S）,sham operation ＋ JNK inhibitor SP600125 （group SP）,BCP group,BCP ＋ dimethyl sulfoxide （DMSO） group,and BCP＋ SP600125 group （group BCP＋ SP）.BCP was induced by injecting Walker 256 mammary gland cancer cells into the bone marrow of the left tibia.On 10-12 days after BCP,SP600125 10 μg（10 μ1） was injected intrathecally once a day in SP and BCP ＋ SP groups,and 5% DMSO 10 μl was injected intrathecally once a day in BCP ＋ DMSO group.Mechanical paw withdrawal threshold （MWT） was measured at 1 day before BCP and 3,6,9,10,11 and 12 days after BCP.After measurement of MWT at 12 days after BCP,the rats were sacrificed and L4-6 segments of the spinal cord were removed for determination of MCP-1 expression by using immuno-histochemistry and Western blot.Results Compared with S group,MWT was significantly decreased at 6-12 days after BCP,MCP-1 expression was upregulated in BCP,BCP ＋ DMSO and BCP ＋ SP groups （P 〈 0.01）,and no significant change was found in the parameters mentioned above in SP group （P 〉 0.05）.Compared with BCP group,MWT was significantly increased at 10-12 days after BCP,MCP-1 expression was down-regulated in BCP ＋ SP group （P 〈 0.01）,and no significant change was found in the parameters mentioned above in BCP ＋ DMSO group （P 〉 0.05）.Conclusion JNK/MCP-1 signaling pathway in the spinal cord may be involved in the maintenance of BCP in rats.