大麻素受体2激动剂JWH-015对骨癌痛大鼠脊髓背角磷酸化环磷酸腺苷反应元件结合蛋白的影响

目的探讨腹腔注射大麻素受体（cannabinoid receptor，CB）2激动剂对骨癌痛大鼠脊髓背角磷酸化环磷酸腺苷反应元件结合蛋白（phosphorylated cyclic AMP respons eclement binding protein，pCREB）表达的影响。方法运用随机数字表法将63只雌性SD大鼠分为3组：肿瘤给药组（J组，15只）、肿瘤对照组（D组，24只）和假手术对照组（S组，24只）。J组、D组的大鼠左侧胫骨上端骨髓腔被注入5μl Walker256大鼠乳腺癌细胞制备骨癌痛模型；S组则注入等量的生理盐水。在造模后第10天，J组腹腔注射JWH-015（100μg/500μ1），D组、s组注射等量JWH-015溶剂二甲基亚砜（dimethylsulfoxide，DMSO）。每组大鼠于造模前1d，造模后4、7、10d，腹腔注射后2、6、24、48、72h，检测手术侧机械刺激缩足阈值（paw withdrawal mechanical threshold，pwMT）和行走痛行为学评分。D组和S组大鼠于造模后4、7d，J组、D组和S组大鼠于造模后10d及腹腔注射后6、24、72h，取脊髓腰膨大进行免疫印迹分析。结果与S组比较，J组和D组大鼠造模后7d PWMT开始降低（P〈0.05），造模后10d行走痛行为学评分增加（P〈0.05），脊髓背角pCREB表达水平于7、10d上调（P〈0.05）.与D组比较，腹腔注射JWH-015后24h，J组PWMT（8.7±1.6）g显著上升（P〈0.05），行走痛行为学评分（1.0±0.6）分和pCREB的表达（0.56±0.10）明显下降（P〈0.05）。结论腹腔注射JWH-015可能通过下调脊髓背角pCREB的表达改善骨癌痛大鼠的痛行为。

The effect of intraperitoneal injection cannabinoid 2 receptor agonist JWH-015 on the expression of phosphorylated cyclic AMP response element binding protein in spinal dorsal horn in a rat model of bone cancer pain

Objective To investigate the change of phosphorylated cyclic AMP response element binding protein （pCREB） in spinal dorsal horn in a rat model of bone cancer pain, after intraperitoneal injection JWH-015. Methods Sixty-three female SD rats were randomly divided into 3 group： medication administration of JWH-015 group （group J, n=15 ）, medication administration of dimethylsulfoxide （DMSO） group （group D, n=l5） and sham group （group S, n=21 ）. Group J, D： 5 μl Walker256 breast cancer cells of rat were implanted into the intramedullary space of the left tibia of rat to induce ongoing bone cancer pain model, rats of group S were implanted 5 μ1 NS. On 10 d after implantation, JWH-015 （100 μg/500 μl） was injected into rats of group J, and DMSO was injected into rats of group D and S. The paw withdrawal mechanical threshold（PWMT） and ambulatory pain of each group were detected on 1 d before implantation, and 4, 7, 10 d after implantation, and 2, 6, 24, 48, 72 h after injection . Then, Lumbar intumescentia of rat were taken out to analyze Western-blotting at 4, 7 d after implantation of group D and S, 10 d after implantation, 6, 24, 72 h after injection of group J, D, S. Results Compared with group S, at day 7 after the implantation, the PWMT of group J and D were significantly decreased （P〈O.05）, at day 10 after the implantation, the ambulatory pain of group J and D were obviously increased. The expression of pCREB in spinal dorsal horn were up-regulated at day 7 and 10 （P〈0.05）. Compared with group D, 24 h after injection, the rat of group J showed remarkable rising of PWMT （8.7±1.6） g and reducing of ambulatory pain （1.0±0.6） and the expression of pCREB （0.56±0.10） （P〈0.05）. Conclusions Iintraperitoneal injection JWH-015 attenuated bone cancer pain. which mav be acted via down-regulating the exnression of nCREB in sninnl dorsal hnrn.