鞘内注射代谢性谷氨酸受体亚型5拮抗剂对骨癌痛小鼠痛行为及脊髓水平星形胶质细胞活化的影响

Intrathecal administration of metabotropic glutamate receptor subtype 5 antagonist on pain behavior and spinal astrocytes activation in mouse mod of bone cancer pain

目的 探讨代谢性谷氨酸受体亚型5（mGluR5）拈抗剂MTEP的抗癌痛作用及其机制.方法 C3H/HeNCrlVr雄性小鼠60只,随机分为：（1）正常组：正常饲养21d;（2）MTEP＋Tumor组：癌痛组从第14d开始鞘内注射MTEP150nmol,1次/d,共7次;（3）生理盐水＋Tumor组：以等体积的生理盐水代替MTEP;（4）MTEP＋Sham组：用等剂量MTEP给予假手术组;（5）生理盐水＋Sham组：用等体积的生理盐水给予假手术组.每组12只小鼠.用热辐射刺激仪测定缩足潜伏期（PWTL）.各组小鼠均在第21d行为学测试后取脊髓标本,分别应用Real-time PCR和western blot检测胶质细胞纤维酸性蛋白（GFAP）mRNA及蛋白的表达.结果 各组小鼠基础PWTL差异无统计学意义（P＞0.05）.在术后14d,与正常组相比,假手术组PWTL差异无统计学意义（P＞0.05）,而癌痛组PWTL明显降低（P＜0.05）.在术后21 d,和正常组相比,MTEP＋Sham组、生理盐水＋ShaT组PWTL、脊髓GFAP表达差异均无统计学意义（P＞0.05）;生理盐水＋Tumor组PWTL[（6.18±1.29）s]明显低于正常组[（15.91±1.65）s]、生理盐水＋Sham组[（16.57±1.86）s]和MTEP＋Sham组[（17.05±2.43）s]（P＜0.05）,脊髓水平GFAP表达则高于上述3组;MTEP＋Tumor组PWTL[（9.39±1.94）s]高于生理盐水＋Tumor组,脊髓水平GFAP表达则低于生理盐水＋Tumor组（P＜0.05）.结论 鞘内注射MTEP具有抗癌痛作用,抑制脊髓水平星形胶质细胞活化可能是其机制之一.

Objective To investigate effects of metabotropic glutamate receptor subtype 5 （mGluR5） antagonist MTEP on the nociceptive behavior and the expression of glial fibrillary acidic protein （GFAP） in spinal cord associated with bone cancer pain. Methods C3H/HeNCrlVr 60 male mice were randomly divided into 5 groups： （ 1 ） normal control group： the mice were given food and water ad libitum; （ 2 ） MTEP ＋ Tumor group： the mice were treated by intrathecal gdministration （ once daily on the days 14 ～20 after inoculation of tumor cells）with MTEP （150 nmol）; （3） physiological saline ＋ Tumor group：the tumor mice were treated with the same volume of physiological saline; （4） MTEP ＋ Sham group： the sham mice were treated with the same dose of MTEP;（5） physiological saline ＋ Sham group： the sham mice were treated with the same volume of physiological saline.the mice pain behaviors were assessed with the paw withdrawal thermal latency （PWTL） at the corresponding time points, then the mice were killed and the samples of spinal cord were used to real-time PCR and western blot detection of GFAP mRNA and protein expression. Results The basic values of PWTL had no significant differences among all groups （P〈0.05）. At day 14 after operation,no significant difference was found in the PWTL value between normal control group and the sham operation group. But in tumor group, the PWTL value was significantly lower than in the normal control group （P〈 0.05 ）. At day 21 after operation,the PWTL and the level of GFAP expression in the spinal cord had no significant differences among normal control group, MTEP ＋ Sham group and physiological saline ＋ Sham group （P 〉 0.05 ）; the PWTL （ （6. 18 ± 1.29 ） s） in physiological saline ＋ Tumor group was significantly lower than in normal control group （ （ 15.91 ± 1.65 ）s）, physiological saline ＋ Sham group （ （ 16.57 ± 1.86） s） and MTEP ＋ Sham group （ （ 17.05 ± 2.43 ） s） （P 〈 0.05 ）, but the level of GFAP expression was higher than in the above three groups. In MTEP ＋Tumor group ,the PWTL （9.39 ± 1.94s） was higher than in physiological saline ＋ Tumor group, and the level of GFAP expression was lower than in physiological saline ＋Tumor group （P 〈 0.05 ）. Conclusion Inhibiting spinal activation of astrocytes may be one of the MTEP anticancer pain mechanisms.