大鼠骨癌痛-慢性吗啡耐受模型的建立

目的 建立大鼠骨癌痛-慢性吗啡耐受模型.方法 鞘内置管成功的成年雌性SD大鼠36只,体重180～200 g,采用随机数字表法,将大鼠随机分为3组(n=12):假手术组(S组)、慢性吗啡耐受组(M组)和骨癌痛+慢性吗啡耐受组(BM组).BM组右侧胫骨上段骨髓腔注入Walker256癌细胞10 μl(4×102个细胞/μl)制备骨癌痛模型,M组注射热灭活的Walker256癌细胞10μl,接种后10 d开始鞘内注射吗啡20μg/kg,2次/d,连续9 d.S组仅暴露右侧胫骨上段.分别于接种Walker256癌细胞前、接种后1、3、6、9 d、给予吗啡1、3、5、7、9 d时测定机械缩足阈值(MWT)和机械缩足持续时间(MWD),并于接种后9 d时行放射学检查,进行骨质破坏评分.最后1次测定痛周后,对右侧足底进行触摸刺激,停止刺激后3 h时取脊髓L4-6节段,测定脊髓背角Foa表达水平.结果 与S组比较,M组MWT降低,MWD延长,脊髓背角Fos表达上调(P＜0.05或0.01);与M组比较,BM组MWT降低,骨质破坏评分升高,MWD延长,脊髓背角Fos表达上调(P＜0.05或0.01).结论 成功制备了大鼠骨癌痛-慢性吗啡耐受模型.

Abstract：

Objective To establish a rat model of bone cancer pain-chronic morphine tolerance. Methods Thirty-six adult female Sprague-Dawley rats weighing 180-200 g in which intrathecal catheters were successfully placed without complications were randomly divided into 3 groups ( n = 12 each) :group sham operation (group S),group chronic morphine tolerance (group M) and group bone cancer pain + chronic morphine tolerance (group BM). Bone cancer pain was induced by intra-tibia inoculation of Walker256 mammary gland carcinoma cells (4 ×102 cells/μl) in group BM, while in group M heat-inactivated Walker256 mammary gland carcinoma cells were given instead, and then 10 days later, intrathecal morphine 20 μg,/kg was administered twice a day for 9 consecutive days. The mechanical paw withdrawal threshold (MWT) and mechanical paw withdrawal duration (MWD) were measured before inoculation, at day 1, 3, 6 and 9 after inoculation, and at day 1, 3, 5, 7 and 9 of morphine administration. The degree of bone destruction was assessed by radiological analysis at day 9 after inoculation. After the last measurement of pain threshold, the rats were given innoxious touch-stimulus. The rats were sacrificed 3 h after stopping the stimulus, and L4-6 segment of the spinal cord was isolated to determine the expression of Fos protein in the spinal dorsal horn. Results Compared with group S, MWT was significantly decreased, MWD was significantly prolonged and the expression of Fos protein was up-regulated in group M ( P ＜ 0.05 or 0.01 ). MWT was significantly decreased, MWD was significantly prolonged, bone destruction scores were significantly increased,and the expression of Fos protein was up-regulated in group BM compared with group M ( P ＜ 0.05 or 0.01 ). Conclusion A rat model of bone cancer pain-chronic morphine tolerance is successfully established.

Establishment of a rat model of bone cancer pain-chronic morphine tolerance

Objective To establish a rat model of bone cancer pain-chronic morphine tolerance. Methods Thirty-six adult female Sprague-Dawley rats weighing 180-200 g in which intrathecal catheters were successfully placed without complications were randomly divided into 3 groups ( n = 12 each) :group sham operation (group S),group chronic morphine tolerance (group M) and group bone cancer pain + chronic morphine tolerance (group BM). Bone cancer pain was induced by intra-tibia inoculation of Walker256 mammary gland carcinoma cells (4 ×102 cells/μl) in group BM, while in group M heat-inactivated Walker256 mammary gland carcinoma cells were given instead, and then 10 days later, intrathecal morphine 20 μg,/kg was administered twice a day for 9 consecutive days. The mechanical paw withdrawal threshold (MWT) and mechanical paw withdrawal duration (MWD) were measured before inoculation, at day 1, 3, 6 and 9 after inoculation, and at day 1, 3, 5, 7 and 9 of morphine administration. The degree of bone destruction was assessed by radiological analysis at day 9 after inoculation. After the last measurement of pain threshold, the rats were given innoxious touch-stimulus. The rats were sacrificed 3 h after stopping the stimulus, and L4-6 segment of the spinal cord was isolated to determine the expression of Fos protein in the spinal dorsal horn. Results Compared with group S, MWT was significantly decreased, MWD was significantly prolonged and the expression of Fos protein was up-regulated in group M ( P ＜ 0.05 or 0.01 ). MWT was significantly decreased, MWD was significantly prolonged, bone destruction scores were significantly increased,and the expression of Fos protein was up-regulated in group BM compared with group M ( P ＜ 0.05 or 0.01 ). Conclusion A rat model of bone cancer pain-chronic morphine tolerance is successfully established.