神经病理性疼痛大鼠海马组织中NF-κB mRNA、iNOS mRNA、nNOS mRNA表达及意义

摘要

目的 探讨神经病理性疼痛大鼠模型海马核因子-KB(NF-KB)mRNA、诱导型一氧化氮合酶(NOS)mR-NA和神经元型一氧化氮合酶(nNOS)mRNA表达及意义.方法 将70只雄性Wister大鼠随机分为实验组和对照组各35只,于慢性坐骨神经挤压性损伤(cci)术前1d及术后1、4、7、14、21、28 d测定机械痛阈及热痛阈后处死大鼠,取海马组织,采用RT-PCR法测定NF-KB mRNA、iNOS mRNA、nNOS mRNA水平.结果 与对照组及术前比较,实验组术后各时点术侧机械痛阈及热痛阈明显降低;NF-KB mRNA水平于术后4d开始增加,7d达到高峰,术后14、28 d仍维持于较高水平(P<0.05):WOS mRNA水平于术后4d开始增加,nNOS mRNA水平于术后7d开始增加,两者均在21d达到高峰,在28 d仍维持在较高水平(P<0.05).结论 CCI参与了神经病理性疼痛的维持,其机制可能为海马组织NF-KB活化并上调NOS和nNOS表达.%Objective To analyze the expressions of nuclear factor-κB (NF-κB) mRNA, inducible nitric oxide synthase(iNOS) mRNA and neuronal nitric oxide synthase (nNOS) mRNA in hippocampus in neuropathic pain model of rats.Methods Seventy male Wister rats were randomly divided into experimental group and observed group with 35 in each,the former received the chronic constriction injury (CCI) and the later received the sham operation. The mechanical and thermal nociceptive thresholds were assessed at 1 d before and 1 d, 4 d, 7 d, 14 d, 21 d and 28 d after CCI operation.Rats were killed and hippocampus were removed at each time point and the expression of NF-κB mRNA, iNOS mRNA and nNOS mRNA in hippocampus were examined by RT-PCR technique. Results Compared with that of the sham group and before operation, the thresholds to mechanical and thermal stimuli of the experimental group decreased obviously after CCI operation. The expression of NF-κB mRNA in the hippocampus began to increase at 4 d after operation, reached the peak at 7 d and maintained at a high level during the 28-day-observation (P ＜ 0.05). The expression of iNOS mRNA began to increase at 4 d after operation and nNOS mRNA began to increase at 7 d ( P ＜ 0.05 ). Both of them reached the peak at 21d and maintained at a high level during the 28-day-observation. Conclusions The activation of NF-κB and the upregulation of iNOS and nNOS in hippocampus may be involved in the procession of neuropathic pain.