化疗性痛动物模型的建立及发病机制探讨

Establishment of chemotherapy-induced neuropathic pain animal model and its pathogenesis

目的利用长春新碱(Vincristine)或紫杉醇(Paclitaxel)建立化疗性痛大鼠模型并探讨该模型的发病机制。方法利用微量释放泵连续给与SD大鼠一定量的长春新碱(Vincristine)或紫杉醇(Paclitaxel),而对照组给与相当量的溶剂。在注射前和注射后的连续时间点观察大鼠的痛觉行为学变化;当痛觉阈值降到最低点时,对处理组和对照组大鼠脊髓背角进行针对星形胶质细胞胶质纤维酸性蛋白(GFAP)和小胶质细胞OX42的免疫荧光染色,并鞘内给药抑制胶质细胞观察镇痛作用,同时取出两组大鼠的新鲜脊髓背角组织进行Western blot分析。结果长春新碱组注射后第6 d出现了明显的机械和热痛觉过敏,到注射后第8 d痛觉阈值降到最低点,以后基本维持在此水平;而紫杉醇组第4 d出现了明显的机械和热痛觉过敏,第12 d痛觉阈值降到最低点,以后基本维持在此水平。与对照组相比,处理组脊髓背角GFAP和OX42的染色密度出现了显著增强,鞘内给予针对星形胶质细胞的特异性抑制剂L-α-氨基己二酸(LAA)和小胶质细胞的特异性抑制剂米诺环素(minocycline)能起到有效镇痛作用。另外处理组脊髓细胞因子白介素-1β(IL-1β)、肿瘤坏死因子-α(TNF-α)和磷酸化丝裂原活化蛋白激酶(MAPK)类分子磷酸化丝裂原活化蛋白激酶p38(p-p38)的表达显著上调。结论我们成功建立了化疗性痛模型,脊髓背角胶质细胞的激活有可能参与了化疗性痛的形成。

Objective The experiment is designed to establish chemotherapy-induced neuropathic pain （CNP） model and investigate the pathogenesis of this model.MIethods Rats were surgically implanted with mini-osmotlc pumps set to continuously deliver Vincristine or Paclitaxel, while the control group were injected with saline. Immunofluorescent staining of glial fibrillary acidic protein （GFAP） or OX42 were used to detect the activation of astrocyte and microglia. L-α-aminoadipate （LAA） and minocycline were used to inactivate astrocyte and microglia, respectively, and to identify the roles of spinal glial cells in the development of CNP. Western blot analysis of interleukin-1 beta （IL-1β）, tumor necrosis factor-α （TNF-α） or anti-phospho-p38 MAPK （P-P38） in both two groups were also performed, Results Compared to control group, the paw withdrawal thresholds of Vincristine group and Paclitaxel group were significantly decreased, indicating that mechanical allodynia occurred in Vincristine or Paclitaxel treated rats. It was found that spinal astrocyte and microglia were dramatically activated in CNP rats. The allodynia was significantly attenuated by intrathecal administration of LAA （astrocytic specific inhibitor） and minocycline （microglial specific inhibitor）, suggesting that spinal astrocytic activation contributed to alledynia in CNP rats. Furthemlore, the expressions of IL-1β and TNF-α were up-regulated and the phosphorylation of p-p38 was enhanced. Conclusion These findings indicate that glial activation is the initiator of CNP, and spinal glial inhibition may hold a therapeutic promise in the treatment of CNP.