中文摘要：

目的评价鞘内注射注射不同剂量硫酸镁对小鼠骨癌痛的影响。方法雄性C3H／HeJ小鼠288只，8～10周，体重18～22g，采用随机数字表法，将其随机分为6组（n=48）：对照组（c组）、假手术组（S组）、骨癌痛＋5出人工脑脊液组（BCP组）、骨癌痛＋14．4ugMgSO4组（M1组）、骨癌痛＋43．2ugMgSO4组（M2组）和骨癌痛＋86．4ugMgSO4组（M3组）。S组右侧股骨骨髓腔内仅注入20ul a-MEM；BCP组、M1组、M2组和M，组注入含有2×10^5个肿瘤细胞的20ul a-MEM制备小鼠骨癌痛模型，各组在接种肿瘤细胞后第14天分别定时鞘内注射人工脑脊液5ul、MgSO4 14．4ug／5ul、43．2ug/5ul、86．4ug／5ul。分别于给药前0．5h（T0）、给药后0．5、2、4、8h（T1～4）时测定机械缩足反射阈值（PWMT）和热缩足反射潜伏期（PWTL），于T0-4时各组随机取8只小鼠处死取脊髓腰膨大，采用免疫组化法检测脊髓含2B亚基的NMDA受体（NR2B）的表达。结果与C组和s组比较，BCP组、M1组、M2组和M1组T0-4时PWMT和PWTL降低，脊髓NR2B表达上调（P〈0．05）；与BCP组比较，M2组和M，组T1-3时PWMT和PWTL升高，脊髓NR2B表达下调（P〈0．05）；与M2组比较，M3组T1～3时PWMT和PWTL升高，脊髓NR2B表达下调（P〈0．05）。结论鞘内注射硫酸镁可减轻小鼠骨癌痛，其效应呈剂量依赖性。

英文摘要：

Objective To investigate the effects of different doses of intrathecal magnesium on bone caneer pain （BCP） in mice.Methods Two hundred and eighty-eight male C3H/HeJ mice, aged 8-10 weeks, weighing 18-22 g, were randomly divided into 6 groups （ n = 48 each） ： control group （group C） ; sham operation group （group S） ; BCP ＋ artificial cerebro-spinal fluid （aCSF） 5 ul group （group BCP） ; BCP ＋ MgSO4 14.4 ug group （group M1）; BCP ＋ MgSO4 43.2ug group （group M2） and BCP ＋ MgSO4 86.4 ug group （group M3）. BCP was produced by injecting fibrosarcoma cells of bone into the medullary cavity of right femur. Intrathecal catheter was placed in the 4 BCP groups. The aCSF 5 ul or MgSO4 14.4 ug/5ul, 43.2 ug/ul , or 86.4 ug/5 ul was injected intrathecaily on 14th day after inoculation of tumor ceils. The paw withdrawal threshold to mechanical stimuli （PWMT） and paw withdrawal latency to thermal stimuli （PWTL） were measured at 0.5 h before administration （T0 ） and at 0.5, 2, 4 and 8 h after administration （T1-4） . Eight animals chosen from each group at T0-4 were sacrificed, and L4.5 segment of the spinal cord was removed for determination of NR2B expression （by immuno-flurorescence） in the spinal cord. Results PWMT and PWTL were significantly decreased at T0-4 , and NR2B expression was significantly up-regnlated at T0-4 in groups BCP, M1 , M2 , M3 compared with groups C and S （ P 〈 0.05）. Compared with group BCP, PWMT and PWTL were significantly increased at T1-3, and NR2B expression was significantly down-regulated at T1-3 in groups n2 and M3 （P 〈 0.05）. Compared with group M2, PWMT and PWTL were significantly increased at T1-3, and NR2B expression was significantly down-regulated at T1-3 in group M3 （ P 〈 0.05）. Conclusion Intrathecal magnesium can reduce BCP in a dose-dependent manner in mice.