艾芬地尔预先给药对CCI大鼠脊髓NMDA受体NR2B亚基表达的影响

Effect of Ifenprodil pretreatment on the expression of NR2B subunit protein of NMDA receptor in the dorsal horn of spinal cord in a rat model of neuropathic pain

目的 探讨艾芬地尔预先给药对坐骨神经慢性压榨性损伤（CCI）大鼠脊髓背角NR2B亚基表达的影响及其对神经病理性疼痛的预防作用。方法 雄性SD大鼠50只，体重180-200g，随机分为3组：假手术组（n=10）、CCI组（n=20）和艾芬地尔组（n=20）。建立CCI动物模型，假手术组大鼠仅分离坐骨神经，但不结扎神经。艾芬地尔组大鼠在术前30min及术后1、2d连续3d腹腔内注射艾芬地尔（10mg，ks）；CCI组大鼠腹腔内注射相同体积的生理盐水；假手术组未给药。各组均于术前，假手术组于假手术后3d、艾芬地尔组和CCI组均于CCI术后7、14d分别取10只大鼠，以yonFrey纤维测定机械痛阈，随后断头处死，取患侧L4,5脊髓背角组织，采用Westernblot方法测定NR2B亚基的蛋白表达。结果 各组术前基础机械痛阈比较差异无统计学意义（P〉0．05）。与假手术组比较，CCI组术后7、14d时机械痛阈降低（P〈0．05），艾芬地尔组术后7、14d时差异无统计学意义（P〉0．05）；与CCI组比较，艾芬地尔组术后7、14d时机械痛阈升高（P〈0．05）。与假手术组相比，艾芬地尔组和CCI组术后7、14d时脊髓背角NR2B蛋白表达均升高（P〈0．05）；与CCI组比较，艾芬地尔组术后7、14d时脊髓背角NR2B蛋白表达降低（P〈0．05）。结论 大鼠腹腔内预先注射艾芬地尔，通过特异性地拮抗含NR2B亚基NMDA受体，可有效地预防CCI导致的神经病理性疼痛，其机制与降低脊髓背角NR2B亚基表达升高有关。

Objective To investigate the effect of ifenprodil pretreatment on the expression of NR2B subunit protein of NMDA receptor in the dorsal horn of spinal cord in a rat model of neuropathic pain. Methods Fifty male SD rats weighing 180-200 g were used in this study, Neuropathic pain was produced by chronic constrictive injury （CCI）. The left sciatic nerve was exposed and 4 loose ligatures were placed on the sciatic nerve at 1-2 mm intervals with 4-0 chromic catgut under pentobarbital anesthesia. The animals were randomly divided into 3 groups： group A sham operation （ n = 10） ; group B CCI （ n = 20） and group C ifenprodil ＋ CCI （ n = 20）. In group C ifenprodil 10 mg·kg^-1 was injected intrapofitoneally once a day for 3 consecutive days （30 min before operation and on postoperative day 1 and 2）, Paw withdrawal threshold to von Frey hair was measured before and after operation, The animals were killed on day 3 after sham operation in group A, In group B and C 10 animals were killed on day 7 after CCI operation and the other 10 animals were killed on day 14 after operation. The L4,5 segment of spinal cord was removed and dorsal horn was isolated for determination of NR2B protein expression by Western blot method, Results Paw withdrawal threshold to von Frey hair stimulation on day 7 and 14 after CCI operation was significantly lower in group B than in group A and C and there was no significant difference between group A and C, The NR2B protein expression in dorsal horn of spinal cord on day 7 and 14 after CCI operation was significantly higher in group B and C than in group A and was significantly lower in group C than in group B, Conclusion Ifenprodil pretreatment can attenuate the neuropathic pain through reducing the increase in NR2B protein expression in dorsal horn of spinal cord induced by CCI.