脊髓胶质细胞在小鼠骨癌痛形成中的作用

Role of gliocyte in spinal cord in development of bone cancer pain in mice

目的评价脊髓胶质细胞在小鼠骨癌痛形成中的作用。方法健康雄性C3H／He小鼠40只，周龄8～10周，体重18～22g，随机分为4组（n=10）：假手术组（S组）、骨癌痛组（B组）、PBS组（P组）和米诺环素组（M组）。S组跟骨骨髓腔内注射PBS10μl；余3组跟骨骨髓腔内注射含2×10^5个骨纤维肉瘤细胞的PBS10μl制备骨癌痛模型，于造模前即刻开始PBS组鞘内注射PBS5μl，M组鞘内注射米诺环素（用PBS溶解为0．2mmol／L）5μl，1次／d，连续11d。于造模前1d、造模后即刻、3、5、7、9、11d时测定机械痛阈；于造模后3、7、9、11d机械痛阚测定结束后测定冷痛阈。痛阈测定结束后处死小鼠，取脊髓组织，测定神经胶质纤维酸性蛋白（GFAP）和CD11b的表达水平。结果与S组比较，B组和P组造模后3～11d时、M组造模后3、5d时机械痛阈升高，B组、P组和M组造模后7～11d时冷痛阈升高，脊髓CD11b和GFAP表达上调（P〈0．05）。与B组比较，M组造模后3～11d时机械痛阈降低，造模后7～11d时冷痛阂降低，脊髓CD11b和GFAP表达下调（P〈0．05）。结论脊髓胶质细胞（星形胶质细胞和小胶质细胞）的激活参与了小鼠骨癌痛的形成。

Objective To evaluate the role of gliocyte in the spinal cord in the development of bone cancerpain （BCP） in mice. Methods Forty male C3H/He mice aged 8-10 weeks weighing 18-22 g were randomly divided into 4 groups （ n = 10 each） ： group I sham operation （group S）, group Ⅱ BCP, group Ⅲ PBS and group Ⅳ minocyline （group M）. In group BCP, PBS and M, bone cancer pain was produced by injection of NCTC2472 fibrosarcoma cell suspension （2 × 10^5 cells） 10 μl into medullary cavity of calcaneus bone, while in group S, PBS solution 10 /11 was injected instead of cancer cell suspension. In group PBS and M, PBS 5 μl and minocyline 5 μl （dissolved to 0.2 mmol/L in PBS） were given IT immediately before cancer cell inoculation once a day for 11 consecutive days respectively. Mechanical pain threshold was measured at 1 d before cancer cell inoculation, and at 0, 3, 5, 7, 9 and 11 d after cancer cell inoculation. Cold pain threshold was measured at 3, 7, 9 and 11 d after cancer cell inoculation. The animals were killed after measurement of pain threshold and L4-6 segment of spinal cord was removed for determination of GFAP and CDllb expression by Western blot. Results Compared with group S, mechanical pain threshold was significantly increased at 3-11 d after cancer cell inoculation in group BCP and PBS, and at 3 and 5 d after cancer cell inoculation in group M, and cold pain threshold was significantly increased at 7-11 d after cancer cell inoculation, and expression of CDllb and GFAP was up-regulated in group BCP, PBS and M （P 〈 0.05）. Compared with group BCP, mechanical pain threshold was significantly decreased at 3-11 d after cancer cell inoculation, cold pain threshold was significantly decreased at 7-11 d after cancer cell inoculation, and expression of CDllb and GFAP was down-regnlated in group M （P 〈0.05）. Conclusion The activiton of gliocyte in the spinal cord is involved in the development of bone cancer pian in mice.