坐骨神经选择性损伤痛模型小鼠脊髓背角线粒体解偶连蛋白UCP4的表达变化

目的:观察线粒体保护蛋白解偶联蛋白4(uncoupling protein 4,UCP4)在坐骨神经选择性损伤(sparednerve injury,SNI)模型小鼠脊髓背角中的表达变化。方法:健康C57BL/6小鼠分为假手术对照组(n=21)和坐骨神经分支选择性损伤SNI组(n=21),实验组损伤后饲养3,7,14 d。行为学采用测定小鼠热痛阈和Von Frey机械性痛阈;用免疫荧光组织化学染色法检测对比小鼠脊髓L3-6节段背角内UCP4免疫阳性细胞的数量。结果:SNI术后3 d,小鼠手术侧热痛阈和机械性痛阈明显低于假手术组,术后14 d达最低值。UCP4分布于正常小鼠脊髓背角,SNI后3 d损伤组小鼠脊髓背角中的UCP4表达降低,图像分析表明UCP4的光密度与对照组比较,差异有统计学意义(P<0.05);脊髓背角中UCP4的表达在14 d时其降低程度最明显,图像分析表明光密度与对照组、3d和7 d比较,差异均有统计学意义(P<0.05)。结论:SNI后脊髓背角线粒体保护蛋白UCP4表达降低可能参与神经病理性疼痛的中枢敏化过程。

Changes of expressions of mitochondrial uncoupling protein 4 in spinal dorsal horn of model mice with spared nerve injury

Objective:To study the changes of mitochondrial protective protein uncoupling protein 4(UCP4)expression in spinal dorsal horn in mice model of spared nerve injury(SNI).Methods:Healthy C57BL/6 adult mice were randomly divided into sham operation group(n=21)and experimental group(n=21),which were killed at day 3,7 and 14 after SNI.The paw withdrawal thermal latency and the paw withdrawal mechanical threshold at the ipsilateral side were used to evaluate the nociceptive behaviours.The distribution and quantity of UCP4 in dorsal horn of lumbar spinal cord(L3-6) was analyzed by immunofluorescence and image analysis methods.Results:On 3 d after SNI,the mean values of the paw withdrawal thermal latency and the paw withdrawal mechanical threshold in SNI side revealed clearly lower than that of sham group.On 14 d after SNI,the values of the paw withdrawal thermal latency and the paw withdrawal mechanical threshold dropped to the lowest.UCP4-immunoreactivity(IR)existed in the spinal dorsal horn in normal mice.A significant decrease of UCP4-IR was noted at day 3 after SNI and the optical density(OD) of UCP4 under image analysis was significantly lower compared with that of control group(P<0.05) at day 3,day 7 and day 14 after undergoing SNI.In addition,the content of UCP4 at 14 d under image analysis was significantly lower compared with that of control group,3 d SNI group and 7 d SNI group(P<0.05).Conclusion:UCP4 might play a role in the regulation of central sensitization of neuropathic pain induced by SNI.