μ受体在抗神经生长因子抗体减轻大鼠骨癌痛中的作用

Role of u-opioid receptor in attenuation of bone cancer pain by anti-nerve growth factor in rats

目的 评价μ受体在抗神经生长因子抗体（anti-NGF）减轻大鼠骨癌痛中的作用.方法 实验一健康雌性SD大鼠60只,体重200～220 g,随机分为4组（n=15）：假手术组（S组）、假手术＋anti-NGF组（SN组）、骨癌痛组（P组）和骨癌痛＋anti-NGF组（PN组）.P组和PN组于左侧胫骨上段骨髓腔内注射10μl Walker256乳腺癌细胞（1×105个）制备骨癌痛模型;S组和SN组于左侧胫骨上段注射PBS 10μl.于肿瘤细胞接种后13 d时,进行鞘内置管.鞘内置管成功后3 d,SN组和PN组鞘内注射anti-NGF 10μg（用生理盐水稀释至10μl）,S组和P组鞘内注射生理盐水10μl,2次/d,连续5 d.于肿瘤细胞接种前、肿瘤细胞接种后13、16、18、21 d时测定自发缩足次数（NSF）、热缩足潜伏期（PWL）和机械性痛阈（PWT）.肿瘤细胞接种后21 d时,处死大鼠,取L4.5段脊髓背角和背根神经节,测定μ受体及其mRNA的表达.实验二健康雌性SD大鼠30只,体重200～220 g,随机分为2组（n=15）：骨癌痛＋anti-NGF组（PN组）和骨癌痛＋纳洛酮＋anti-NGF组（PNN组）.于左侧胫骨上段骨髓腔内注射10μlWalker256乳腺癌细胞（1×105个）制备骨癌痛模型.于肿瘤细胞接种后13 d时,进行鞘内置管.鞘内置管成功后3 d,PN组鞘内注射鞘内注入anti-NGF 10μg（生理盐水稀释至25μl）;PNN组鞘内注射纳洛酮10μg（生理盐水稀释至25μl）,0.5 h后,鞘内注射anti-NGF 10μg（生理盐水稀释至25 μl）,2次/d,连续5 d.于肿瘤细胞接种前、肿瘤细胞接种后13、16、18、21 d时测定大鼠NSF、PWL和PWT.结果 实验一与S组比较,SN组NSF、PWL和PWT差异无统计学意义,SN组和PN组μ受体及其mRNA表达差异无统计学意义（P＞0.05）,P组和PN组瘤细胞接种后13～21 d时NSF增加,PWL缩短,PWT降低,P组μ受体及其mRNA表达下调（P＜0.05或0.01）;与P组比较,PN组肿瘤细胞接种后18～21 d时NSF减少,PWL延长,PWT升高,μ受体及其mRNA表达上调（P＜0.05或0.01）.实验二与PN组比较,PNN组肿瘤细胞接种后18～21 d时NSF增加,PWL缩短,PWT降低（P＜0.05或0.01）.结论 anti-NGF减轻大鼠骨癌痛与μ受体的激活有关.

Objective To evaluate the role of μ-opioid receptor （MOR） in attenuation of bone cancer pain by anti-nerve growth factor （anti-NGF） in rats. Methods Part Ⅰ Sixty female SD rats weighing 200-220 g were randomly divided into 4 groups （n = 15 each）： sham operation group （group S）, sham operation ＋ anti-NGF group （group SN）, bone cancer pain group （group P） and bone cancer pain＋ anti-NGF group （group PN） . Bonecancer was induced by intra-tibial inoculation of 1 × 105 Walker 256 breast cancer cells in group P and PN. Group S and SN received injection of PBS 10 μl. APE 10 catheter was inserted at L2,3 interspace into the epidural space 13 days after cancer cell inoculation. Three days after the catheter was successfully placed, group SN and PN received intrachecal （IT） injection of anti-NGF 10 μg （in normal saline （NS） 10 μl） and group S and P IT injection of NS 10 μl twice a day for 5 consecutive days. The number of spontaneous flinches （NSF）, paw withdrawal latency （PWL） and paw withdrawal threshold （PWT） were measured before and 13, 16, 18, 21 day after cancer cell inoculation. The animals were sacrificed at 21 day after cancer cell inoculation and the spinal cord dorsal horn and dorsal root ganglion were removed for determination of MOR and MOR mRNA expression. Part Ⅱ Thirty female SD rats weighing 200-220 g were randomly divided into 2 groups （n = 15 each）： bone cancer pain ＋ anti-NGF group （group PN） and bone cancer pain ＋ naloxone ＋ anti-NGF group （group PNN）. Bone cancer was induced by intratibial inoculation of 1 × 105 Walker 256 breast cancer cells. APE 10 catheter was inserted at L2-3 interspace into the epidural space 13 days after cancer cell inoculation. Three days after the catheter was successfully placed,group PN received IT injection of anti-NGF 10 μg （in NS 10 μl） and group PNN IT injection of naloxone 10μg （in NS 25 μl） and 0.5 h later IT injection of anti-NGF 10 μg （in NS 25μl） twice a day for 5 consecutive days. NSF,PWL and PWT were measured before and 13, 16, 18, 21 days after cancer cell inoculation. Results Part ⅠCompared with group S, no significant change was found in NSF, PWL and PWT in group SN, and in MOR and MOR mRNA expression in group SN and PN （P 〉 0.05）, NSF was significantly increased, PWL shortened, PWT decreased at 13-21 days after inoculation in group P and PN, and MOR and MOR mRNA expression was down-regulated in group P （P 〈 0.05 or 0.01）. Compared with group P, NSF was significantly decreased, PWL prolonged, PWT increased, MOR and MOR mRNA expression was up-regulated in group PN at 18-21 days after inoculation （P 〈 0.05 or 0.01）. Part Ⅱ Compared with group PN, NSF was significantly increased, PWL shortened, PWT decreased at 18-21 days after inoculation in group PNN （P 〈 0.05 or 0. 01）. Conclusion The mechanism by which anti-NGF attenuates bone cancer pain in rats is related to the activation of MOR.