腹腔注射NR2B抗体对大鼠慢性神经病理性痛的镇痛效应

Analgesic effect of intraperitoneal injection of NR2B antibody on chronic neuropathic pain in rats

目的评价N-甲基-D-天门冬氨酸受体2B亚基(NR2B)抗体治疗对大鼠慢性神经病理性痛的镇痛效应。方法50只成年雄性SD大鼠随机分为5组:对照组(n=7),大鼠不进行任何处理;SNI组(n=7),大鼠左后肢行保留性神经损伤术(spare nerve injury,SNI);NR2B组(n=12)和ifenprodil组(n=12),分别于SNI术后6d、11d腹腔注射10mg/kg的NR2B单克隆抗体(mAbNR2B)或ifenprodil(选择性NR2B拮抗剂);morphine组(n=12),于术后2-4周每次痛阈测试前15min腹腔注射10mg/kg的吗啡。持续观察大鼠痛行为学,分别于SNI术前、术后1-4周内每周测定大鼠的机械缩爪阈值(MWT)和热缩爪持续时间(TWD)。于术后4周测痛后取大鼠L4-6脊髓组织,Western-blot法和免疫组织化学法检测NR2B的含量及表达的变化。结果与对照组比较,SNI组术后1周大鼠出现痛行为学改变,MWT降低(P<0.05)和TWD延长(P<0.05),并持续至术后4周(P<0.05)。术后2周,NR2B组和ifenprodil组大鼠痛行为学症状明显减轻,MWT升高(P<0.05)和TWD缩短(P<0.05),持续至术后4周(P<0.05)。morphine组大鼠有痛行为学改变,术后1-4周MWT和TWD与对照组比较无统计学差异(P>0.05)。术后4周,SNI组大鼠脊髓组织中NR2B的表达及含量升高。与SNI组比较,NR2B组和ifenprodil组大鼠NR2B的表达及含量降低,morphine组NR2B的表达及含量未见降低。结论SNI诱导的慢性神经病理性痛大鼠腹腔注射NR2B抗体,可通过下调脊髓组织中NR2B的高表达产生镇痛效应。

Objective To investigate the analgesic effect of monoclone antibody NR2B（mAbNR2B）on chronic neuropathic pain. Methods Fifty adult male Sprague-Dawley（SD）rats weighing 250 - 300 g were randomly divided into 5 groups：blank control group （ n = 7）, SNI group（ n = 7）, NR2B group（ n = 12）, ifenprodil group（ n = 12）and morphine group（ n = 12）. After SNI surgery, mAbNR2B（10 mg/kg）and ifenprodil（a selective NR2B antagonist）were intraperitoneally injected in NR2B group and ifenprodil group at days 6 and 11, respectively. In morphine group, morphine（ 10 mg/kg, i. p. ）was acutely administered for 15 min before behavioral testing from week 2 to week 4 after SNI. Mechanical withdrawal threshold（MWT）and thermal withdrawal duration（TWD）were measured before SNI（baseline）and once a week from week 1 to week 4 after SNI. Lumbar segment of spinal cord（L4-6）was removed at week 4 after SNI for determining NR2B expression by Western blot and immunohistochemistry. Results Compared with control group, allodynia behavior was observed at week 1 after SNI, MWT decreased and TWD increased（P 〈 0.05）. SNI-induced mechanical allodynia was significantly alleviated, MWT increased and TWD decreased at week 2 after intraperitoneal injection in NR2B group and ifenprodil group（P 〈 0.05）. In morphine group, allodynia behavior was observed from week 1 to week 4 after SNI, but MNT and TWD had no significant difference between morphine group and control group（P 〉0.05）. Compared with control group, the expression of NR2B significantly increased in SNI group at week 4（P 〈 0.05）, decreased in NR2B group and ifenprodil group, but did not change in morphine group. Conclusion NR2B antibody have analgesic effect on SNI-induced chronic neuropathic pain by downregulating high expression of NR2B.