中文摘要：

疼痛多肽肾上腺髓质素（adrenomedullin，AM）在病理性疼痛的产生中发挥重要作用。本研究旨在探讨AM在骨癌痛中的作用及其机制。在SpragueDawley（SD）大鼠胫骨骨髓腔接种Walker256乳腺癌细胞建立骨癌痛模型，术后15天鞘内插管给予选择性AM受体拮抗剂AM珏川检测大鼠机械痛阈变化，用实时荧光定量PCR（quantitativereal—timePCR，qPCR）检测背根神经节（dorsalrootganglion，DRG）CC趋化因子配体2（cochemokineligand2，CCL2）mRNA表达变化，用免疫荧光双标染色法检测CCL2和AM在DRG中的表达定位。结果显示，肿瘤细胞接种第6至15天，骨癌痛大鼠接种侧后足机械痛阈降低；接种后第15天胫骨骨质明显被破坏、骨密度降低，DRGCCL2mRNA表达相对对照组增加约3倍（P〈0．001）。鞘内注射AM22。能使后足机械痛阈值回升到正常，并抑制骨癌诱发的CCL2mRNA增加（P〈0．001）。CCL2在正常大鼠DRG神经元有表达，且多与AM分布在相同细胞上。以上结果提示，AM在骨癌痛的产生中发挥作用；DRG中AM活动增加会上调CCL2的表达，可能是继发性骨癌时AM参与诱发痛觉高敏产生的细胞学机制。

英文摘要：

The pain pepfide adrenomedullin （AM） plays a pivotal role in pathological pain. The present study was designed to investi- gate the effect of blockade of AM receptor on bone cancer pain （BCP） and its mechanism. BCP was developed by inoculation of Walker 256 mammary gland carcinoma cells in the tibia medullary cavity of Sprague Dawley rats. The selective AM receptor antago- nist AM22-52 was administered intrathecally on 15 d after the inoculation. Quantitative real-time PCR was used to detect mRNA level of CC chemokine ligand 2 （CCL2） in dorsal root ganglion （DRG）. Double immunofluorescence staining was used to analyze the localizations of CCL2 and AM in DRG of normal rats. The results showed that, from 6 to15 d after the inoculation, the animals showed significant reduction in the mechanical pain threshold in the ipsilateral hindpaw, companied by the decline in bone density of tibia bone. The expression of CCL2 mRNA in DRG of BCP rats was increased by 3 folds （P 〈 0.001 vs saline group）. Intrathecal administration of AM2：.52 abolished bone cancer-induced mechanical allodynia and increase of CCL2 mRNA level （P 〈 0.001）. In normal rats, CCL2 was co-localized with AM in DRG neurons. These results suggest that AM may play a role in the pathogenesis of BCP. The increased AM bioactivity up-regulates CCL2 expression in DRG, which may contribute to the induction of pain hypersensi- tivity in bone cancer.