槐果碱对SNI致神经病理性疼痛小鼠脊髓组织TLR4/p38 MAPK的影响

摘要

目的 观察槐果碱(sohpocarpine,SC)对坐骨神经分支保留性损伤(spared nerve injury,SNI)致小鼠神经病理性疼痛的缓解作用,并探讨其部分作用机制.方法 将60只♂ ICR小鼠随机分为6组,分别为:假手术组(control)、神经病理性疼痛模型组(model)、普瑞巴林阳性对照组(SNI+普瑞巴林10 mg·kg-1)、槐果碱高、中、低剂量组(SNI+sophocarpine 40、20、10 mg·kg-1).采用SNI法建立小鼠神经病理性疼痛动物模型,于术前1 d、术后d 7(给药前d 1)及给药后1、3、5、7 d测定小鼠机械缩足反射阈值(paw withdrawal mechanical threshold,PWMT)、热刺激缩足反应潜伏期(paw withdrawal thermal latency,PWTL)及冷缩足反射次数(cold withdrawal times,CWT);采用RT-PCR和Western blot法检测槐果碱对SNI损伤小鼠脊髓组织TLR4、p38 MAPK、IL-1β、TNF-α mRNA及蛋白表达的影响.结果 与假手术组比较,SNI致神经病理性疼痛模型组小鼠术后PWMT明显降低、PWTL明显缩短、CWT明显增多;小鼠脊髓组织p38 MAPK、TLR4、TNF-α、IL-1β mRNA和蛋白表达水平明显上调.与模型组小鼠比较,SNI+槐果碱40 mg·kg-1组小鼠给药后PWMT明显升高、PWTL延长、CWT减少;小鼠脊髓组织p38 MAPK、TLR4、TNF-α、IL-1β mRNA和蛋白表达水平明显下调.结论 槐果碱对SNI致神经病理性疼痛有较好的缓解作用,其机制可能与其下调TLR4、p38 MAPK、IL-1β及TNF-α表达水平有关.%Aim To observe the ameliorating effects of sophocarpine on mice with neuropathic pain induced by spared nerve injury(SNI), and to explore the analgesic mechanism.Methods Sixty male ICR mice were randomly divided into six groups: sham-operated, neuropathic-pain model(SNI), SNI+Pregabalin(Pre) 10 mg·kg-1, SNI+SC 40 mg·kg-1, 20 mg·kg-1 and 10 mg·kg-1 group.Neuropathic-pain mouse models were established by SNI of the sciatic nerve.The paw withdrawal mechanical threshold(PWMT), paw withdrawal thermal latency(PWTL), and cold withdrawal times(CWT) were detected to assess the analgesic effects of sophocarpine on mice with neuropathic pain induced by spared nerve injury.The expressions levels of TLR4, p38 MAPK, IL-1β and TNF-α mRNA and protein in spinal cord tissue were detected by reverse transcription-polymerase chain reaction(RT-PCR) and Western blot methods.Results Compared with sham group, the SNI group′s PWMT decreased, PWTL was shorten, CWT increased, and the expression levels of p38 MAPK, TLR4, TNF-α and IL-1β mRNA and protein in spinal cord tissue were up-regulated.Compared with SNI model group, the sophocarpine 40 mg·kg-1 group′s PWMT increased, PWTL was lengthened, CWT decreased, and the expression levels of p38 MAPK, TLR4, TNF-α and IL-1β mRNA and protein in spinal cord tissue were down-regulated.Conclusion Sophocarpine has the analgesic effects on neuropathic pain induced by SNI, and its mechanism may be related to the down-regulation of TLR4, p38 MAPK, IL-1β and TNF-α expression levels.