N-甲基-D-天冬氨酸受体2B亚基在骨癌痛小鼠脊髓背角和背根神经节中的表达

目的：通过观察骨癌痛小鼠疼痛行为学变化和脊髓背角与背根神经节N-甲基-D-天冬氨酸受体2B亚基（the 2B subunits of N-methyl-D-aspartate receptors，NR2B）的表达以及它们之间的相关性，探讨NR2B在癌性痛产生和维持中的作用。方法：选用45只成年雄性C57BL/6小鼠，随机分为3组，模型组（n=15）：于小鼠股骨远端骨髓腔内接种Lewis肺癌细胞2×106个，接种体积为10 μL；假手术组（n=15）：接种等体积的D-Hank’s液；正常对照组（n=15）：不予任何处理。术后第3天始隔日观察小鼠自发痛行为及测定机械性触诱发痛。术后第7，15，23天，各组任选5只取小鼠术侧后肢，HE染色，光镜下观察肿瘤生长及骨质破坏的程度；取腰段脊髓膨大（L2-4）和L4背根神经节行NR2B免疫组织化学检测。结果：通过小鼠行为学测定和组织学检测证实骨癌痛模型制备成功。NR2B在模型组术侧脊髓背角和背根神经节免疫反应阳性指数各时间点明显高于假手术组和正常对照组（P<0.05）。模型组中术侧第7与15，23天比较差异有统计学意义（P<0.05）。各组小鼠术后第23天，术侧脊髓背角和背根神经节NR2B免疫反应阳性指数与小鼠术侧后爪累计抬足时间明显正相关（分别为r=0.976,P<0.001；r=0.882,P<0.001）；与小鼠术侧机械性缩足阈值明显负相关（分别为r=-0.879,P<0.001；r=-0.760,P=0.001）。结论：骨癌痛小鼠脊髓背角和背根神经节中NR2B受体表达均增加，且与行为学表现有明显的相关性，推测脊髓背角和背根神经节的NR2B受体在小鼠骨癌痛产生和维持中起重要作用。

Expression of NR2B in the spinal dorsal horn and dorsal root ganglia in mice with bone cancer pain

ObjectiveTo investigate the manifestation of ethology and the immunohistochemistry results of the 2B Subunits of N-methyl-D-aspartate receptors (NR2B) in the spinal cord dorsal horn and dorsal root ganglia (DRG) in mice with bone cancer pain and their correlation, and to discuss the role of NR2B in the generation and maintenance of bone cancer pain. MethodsForty-five male C57BL/6 mice were randomly divided into 3 groups: a model group (n=15), 2×106 cells in 10 μL D-Hank’s were injected into the left femur of mice；a sham group(n=15), only 10 μL D-Hank’s injected into the left femur of mice；and a normal control group(n=15), no treatment. Spontaneous lifting duration and mechanical withdrawal threshold of the hind paw of mice were measured on alternative days throughout the experiment. Bones from 5 mice in each group were stained with HE on Day 7, 15, and 23 after the inoculation and segments of lumbar spinal cord and L4 DRG were taken to detect NR2B by immunohistochemistry. ResultsBone cancer pain models were successfully established and confirmed by ethology and histology. The immunohistochemical positive indexes of NR2B were significantly higher in the model group than in the sham group and the control group. In the model group there were obvious differences either between Day 7 and Day 15, or between Day 7 and Day 23 (P<0.05). On Day 23, the immunohistochemical positive indexes of NR2B in the ipsilateral spinal cord dorsal horn of all groups, and L4 DRG were positively correlated with the spontaneous lifting duration of ipsilateral hindpaw (r=0.976, P<0.001; r=0.882, P<0.001， respectively), negatively correlated with the mechanical withdrawal threshold of ipsilateral hindpaw (r=-0.879, P<0.001; r=-0.760, P=0.001，respectively). ConclusionThe immunohistochemical positive indexes of NR2B are increased and significantly correlated with the manifestation of ethology. NR2B in the spinal cord and L4 DRG may participate and mediate in forming and developing hyperalgesia in bone cancer pain.