鞘内注射巴氯芬对镜像痛大鼠机械痛敏的影响

目的探讨鞘内注射巴氯芬对镜像痛大鼠机械痛敏的影响。方法选取SD大鼠40只,随机分为3组：模型组（n=24）、模型对照组（H组,n=8）、正常组（W组,n=8）。将Walker256乳腺癌细胞注入左侧胫骨髓腔制备大鼠癌痛模型,然后将模型组大鼠24只,随机分成3组（n=8）：Ⅰ组鞘内注射生理盐水;Ⅱ组、Ⅲ组分别鞘内注射巴氯芬0.1μg及0.3μg。术后9d鞘内给药,注射容积10μl。给药前0.5h（T1）、给药后的0.5、1、2、4、8、24h测定大鼠双足机械缩爪阈值（MWT）、评价运动功能。结果Ⅱ组、Ⅲ组在鞘内给药后0.5h开始痛阈值明显增加,与Ⅰ组比较差异有统计学意义（P〈0.01）;Ⅱ组、Ⅲ组大鼠运动功能不受明显影响。结论鞘内注射巴氯芬可以明显降低由骨癌痛模型引发镜像痛的机械痛敏。

Effects of intrathecal injection of baclofen on mechanical hyperalga of mirror image pain in rats

Objective To explore the effects of intrathecal injection of baclofen on mechanical hyperalga of mirror image pain in rats.Methods 40 SD rats were randomly divided into three groups：model group（n=24）,model control group（group H,n=8）and normal group（group W,n=8）.After the rat model of cancer-induced pain were established by injecting the cancer cells of Walker 256 into left tibia cavum ossis,24 rats in model group were randomly subdivided into three groups（n=8）：groupⅠ（intrathecal injection of normal saline）,groupⅡ（intrathecal injection of 0.1 μg baclofen）and group Ⅲ（intrathecal injection of 0.3 μg baclofen）.All of the rats in these three subgroups were given the corresponding medicine at 9 d after operation and the injection volume was 10 μl.Mechanical withdrawal threshold（MWT）of both hind legs was measured at 0.5 h pre-administration and 0.5,1,2,4,8,24 h post-administration,and the motor function was recorded at the same time points.Results A significant increase in MWT was found in group Ⅱand Ⅲ compared with group Ⅰat 0.5 h after intrathecal administration（P0.01）.No influence on the motor function was observed in group Ⅱand Ⅲ.Conclusion Intrathecal injection of baclofen can obviously lower the mechanical hyperalga of mirror image pain induced by the bone cancer model of rats.