【摘要】 目的:探索脊髓背角胶质细胞及p38 MAPK在髓核致炎大鼠神经根痛中表达的变化。方法:雄性成年SD大鼠66只,随机分为3组:Blank组(12只)、Sham组(12只)、手术模型组(NP组,42只)。检测所有大鼠术前1天,术后1、3、7、12、14、21和28天的50%机械性缩足阈值(50%MWT)。取各组大鼠术后1、3、7、14和28天术侧腰段脊髓背角,免疫荧光检测胶质细胞和p-p38表达与变化及p-p38与胶质细胞共表达情况。另一雄性成年SD大鼠84只,随机分为5组:Blank(12只),Sham(12只),NP(12只),DMSO(12只)和p38 MAPK抑制剂SB203580组(SB组,36只),DMSO组和SB组于术后第2天经硬膜外腔分别给予50μl 10%DMSO和0.1%SB203580,检测所有大鼠术前1天,术后1、2天及给药后1 h、3 h、5 h、7 h、12和24 h的50%MWT。Blank组,Sham组和NP组于术后第2天、DMSO组于给药后3 h取材,SB组分别于给药后3 h、7 h、12 h、24 h取材,Western blot检测p38和p-p38蛋白表达。结果:与Blank组相比,Sham组50%MWT仅在术后1 d下降(P<0.05),NP组各时点的50%MWT明显降低(P<0.05),可持续至术后28天。NP组胶质细胞和p-p38蛋白在术后不同时点发生表达(P<0.05),免疫荧光双标显示p-p38大量表达于小胶质细胞。SB组在给药后3 h 50%MWT明显升高,持续到给药后12 h(P<0.05),Western blot结果显示给药后3~12 h p-p38蛋白表达降低(P<0.05)。结论:在髓核致炎神经根痛大鼠脊髓背角中出现胶质细胞激活及p-p38蛋白表达,给予p38 MAPK特异性抑制剂后痛敏发生改善,胶质细胞及p38 MAPK参与了髓核致炎大鼠神经根痛的发生和发展。更多还原

【Abstract】 Objective To investigate the activation of glial cells and p38 MAPK in the spinal dorsal horn in rat model with inflammatory radicular pain induced by nucleus pulposus. Methods The experiment was carried out in two parts. In part one, 66 adult male SD rats were randomized into three groups: Blank(n = 12), Sham(n = 12) and Model(NP, n = 12). 50% MWT was tested at the time of 1 day before surgery and 1, 3, 7, 12, 14, 21 and 28 days after surgery in each group. On postoperative day 1, 3, 7, 14 and 28, the lumbar segments of spinal dorsal horns ipsilaterally to the surgery position in each group were removed to detect the activation of glial cells and phosphorylation of p38 MAPK(p-p38 MAPK) by immunofluorescence. Immunohistochemical double-staining method was applied to observe the co-expression of p-p38 and glial cells. In part II, 84 adult male SD rats were randomized into 5 groups: Blank(n = 12), Sham(n = 12), NP(n = 12), DMSO(n = 12) and SB(n = 36). 50 μl of 0.1% SB203580 or 10% DMSO was epidurally administrated in Group SB or DMSO on postoperative day 2. 50% MWT was measured at 1 day before surgery and 1, 3, 5, 7, 12 and 24 hours after administration in each group. The spinal dorsal horns were harvested on day 2 in the group of Blank, Sham and NP, and 3 hours after drug administration in group DMSO, and 3, 7, 12, 24 hours after drug administration in group SB for the determination of p38 and p-p38 expression through Western blot technique. Results Compared with the Blank, 50% MWT was decreased only in postoperative day 1(P < 0.05), and then returned to preoperative levels gradually in Sham. 50% MWT was obviously decreased and lasted for 28 days. Meanwhile, glial cells of spinal dorsal horn were activated in group NP(P < 0.05). Double immunofluorescence labelling localized p-p38 to the microglia. Compared with group DMSO, 50% MWT was increased from 3 hours to 12 hours after epidural application of SB203580 on postoperative day 2(P < 0.05), accompanied by down-regulated expression of p-p38 protein(P < 0.05). Conclusion: The expression of glial cells and p-p38 of spinal dorsal horn was upregulated in rat model with inflammatory radicular pain, and the hyperalgesia was alleviated by epidurally administration of SB203580. Activation of glial cells and p38 MAPK in spinal dorsal horn participate in the onset and maintenance of the rat model with inflammatory radicular pain induced by nucleus pulposus.更多还原