氟比洛芬酯对神经病理性疼痛大鼠脊髓背角p38丝裂原活化蛋白激酶活化的影响

Effects of flurbiprofen axetil on activation of p38 mitogen activated protein kinase in spinal cord dorsal horn following neuropathic pain in rats

目的 观察氟比洛芬酯对神经病理性疼痛大鼠脊髓背角p38丝裂原活化蛋白激酶（p38 MAPK）表达的影响.方法 成年健康雄性SD大鼠108只,体质量200 ～ 250 g,采用随机数字表法,将其随机分为3组（n=36）：假手术组（S组）、神经病理性痛组（NP组）和氟比洛芬酯组（F组）.S组仅分离坐骨神经但不结扎,NP组和F组采用坐骨神经慢性压迫损伤法建立神经病理性痛模型.F组于术毕开始腹腔注射氟比洛芬酯10 mg/kg,1次/d,连续14 d;S组和NP组以等容量生理盐水替代.于术前1d、术后3、7、14 d时测定热缩足反射潜伏期（PWL）,并于术后3、7、14d时测定痛阈后各取12只大鼠处死,采用Western blot法测定脊髓背角环氧合酶-2（COX-2）、总p38MAPK（t-p38MAPK）和磷酸化p38MAPK （p-p38MAPK）蛋白表达水平.结果 与S组比较,术后3～14d时PWL在NP组[（3.34±0.22）、（3.54±0.47）、（3.84±0.55）s]和F组[（7.68±0.61）、（8.76±0.71）、（9.68±0.83）s]缩短,术后3～7d脊髓背角COX-2的表达在NP组（3.34±0.22、3.58±0.35）和F组（1.88±0.23、1.56±0.17）上调（P＜0.05）,p-p38MAPK蛋白表达在NP组（36.8±4.1、35.6±3.8）和F组（26.6±3.9、20.4±2.4）升高（P＜0.05）;与NP组比较,F组术后3～14dPWL[（7.68±0.61）、（8.76±0.71）、（9.68±0.83）s]延长,术后3～14d脊髓背角COX-2的表达（1.88±0.23、1.56±0.17、1.03±0.09）下调,p-p38MAPK蛋白表达（26.6±3.9、20.4±2.4、13.6±2.1）降低（P＜0.05）;3组各个时间点脊髓背角t-p38MAPK蛋白表达差异无统计学意义（P＞0.05）.结论 氟比洛芬酯可减轻大鼠神经病理性痛,其机制可能与抑制脊髓背角p38MAPK活化有关.

Objective To investigate the effects of flurbiprofen axetil on activation of p38 mitogen activated protein kinase （p38MAPK） in spinal cord dorsal horn following neuropathic pain in rats.Methods One hundred and eight male SD rats weighing 200-250 g were randomly divided into 3 groups （n =36 each）：sham operation group （S group）,neuropathic pain （NP） group and flurbiprofen axetil group （F group）.In NP and F groups,4 ligatures were placed on the right sciatic nerve at 1 mm intervals with 4-0 silk thread according to the method described by Bennett et al.In S group,the right sciatic nerves were exposed,but not ligated.In F group,flurbiprofen axetil （10 mg/kg） was injected intraperitoneally once a day starting from the end of operation until one day before the animals were sacrificed,while the rats received the equal volume of normal saline （5 ml/kg） instead of F in S and NP groups.One day before operation and 3,7 and 14 days after CCI （T0-3）,paw withdrawal latency to thermal nociceptive stimulus （PWL） was measured.The animals were killed on the postopertive day 3,7 and 14.The lumbar segments （L4-6） of the spinal cord were immediately removed.The activity of p38MAPK and expression of cyclooxygenase-2 （COX-2） in the dorsal horn of the spinal cord were measured by Western blotting.Results As compared with S group,PWL was significantly decreased in NP group [（3.34 ± 0.22）,（3.54±0.47）,（3.84±0.55） s] and F group [（7.68±0.61）,（8.76±0.71）,（9.68 ±0.83） s] at 3,7,14 days after incision （P ＜ 0.05）,and the expression of COX-2 and p-p38MAPK wasup-regulated in the spinal dorsal horn at 3rd and 7th day after incision （P ＜ 0.05）.As compared with NP group,PWL was significantly prolonged in F group [（7.68 ±0.61）,（8.76 ±0.71）,（9.68 ±0.83） s] at 3rd,7th,and 14th day after incision （P ＜0.05）,and the expression of COX-2 （1.88 ±0.23,1.56 ±0.17,1.03 ± 0.09） and p-p38MAPK （26.6 ± 3.9,20.4 ± 2.4,13.6 ± 2.1） was down-regulated at 3rd,7th,and 14th day after incision （P ＜ 0.05）.Conclusion Flurbiprofen axetil can attenuate neuropathic pain through inhibiting phosphorylation of p38MAPK in spinal dorsal horn.