锌对神经病理性疼痛模型小鼠脊髓后角磷酸化的细胞外信号调节激酶表达的影响

Effect of zinc on the pERK expression in the spinal posterior horn of neuropathic pain mice

目的：研究锌对神经病理性疼痛（NPP）模型小鼠脊髓后角磷酸化（p）的细胞外信号调节激酶（ERK）表达的影响。方法：C57／BL6小鼠随机分4组，对照组正常喂养2周后足底注射生理盐水；正常喂养2周后足底注射辣椒素；低锌喂养（锌0．85mg／kg）2周后足底注射辣椒素；高锌喂养（227mg／L）2周后足底注射辣椒素。应用原子吸收光谱、热痛阈检测、免疫组织化学和图像分析技术检测注射后7d锌对动物行为学以及脊髓后角pERK表达的影响。结果：对照组小鼠血清和脊髓中含有丰富的锌离子，脊髓后角有少量pERK表达；当足底注射辣椒素致痛后，血清和脊髓中的锌减少，热痛敏增加，脊髓后角pERK表达增多；低锌喂养能加重缺锌和热痛敏，脊髓后角pERK表达更多；高锌喂养能使血清和脊髓锌增多，降低热痛敏和脊髓后角pERK表达。结论：锌能抑制NPP模型小鼠热痛敏和脊髓后角pERK的表达，锌可能参与了神经病理性疼痛的形成与维持。

Objective： To observe the effect of zinc on the expression of phosphorylative extracellular signal-regulate kinase （pERK） in the spinal posterior horn of neuropathic pain （NPP） model mice. Methods： Mice were divided into 4 groups： （1） a control group, normally fed mice were infected with physiological saline （2） normally fed mice （2 weeks） were infected with capsaicin; （3） low level zinc fed mice （2 weeks） were infected with capsaicim （4） high level zinc fed mice （2 weeks） were infected with capsaicin. Atomic absorption spectrum,heat pain threshold, immunohistochemistry and image analysis were used to test the effect of zinc on the behavior and expression of pERK in the spinal posterior horn of the model mice. Results： The level of zinc in the spinal cord and serum decreased after the normally fed mice had been injected with capsaicin, while the pERK in the spinal posterior horn and the thermohyperalgesia were increased. The deficiency of zinc in the serum and spinal was aggravated in low zinc fed, while the expression of pERK in the spinal posterior horn of the model mice and the thermohyperalgesia were increased. The zinc content in serum and spinal was increased in the high zinc fed mice, while the expression of pERK in the model mice the spinal posterior horn and the thermohyperalgesia were decreased. Conclusion： Zinc could inhibit the thermohyperalgesia and the pERK expression in the spinal posterior horn of NPP model and might take part in the formation and preservation of NPP.