摘要
目的研究神经病理性痛状态下,褪黑素(MLT)是否在脊髓水平参与镇痛效应的调节及其可能的受体机制。方法采用雄性C57BL/6小鼠,进行坐骨神经部分损伤(SNI)模型及假手术(Sham)造模,7 d后鞘内分别给予MLT以及MLT不同受体激动剂和/或拮抗剂,运用von Frey丝测试比较SNI组及Sham组给药前后小鼠机械刺激缩足反应阈值,即机械痛阈值的变化。以雄性C57BL/6和转基因小鼠为研究对象,采用免疫荧光染色技术明确不同类型脊髓背角神经元上MLT受体的表达情况。通过膜片钳技术比较SNI造模及Sham术药物干预前后,脊髓背角神经元兴奋性的改变。结果与Sham组相比,SNI组小鼠的机械痛阈值明显降低(P<0.05);鞘内给予MLT和Ramelteon(MT1/MT2受体激动剂)均能显著恢复SNI组小鼠的机械痛阈值(P<0.05),但同时给予Ramelteon+4PP(MT2受体拮抗剂)后SNI组小鼠的机械痛阈值未恢复。免疫荧光结果表明,MT2广泛分布于小鼠脊髓背角的兴奋性神经元。膜片钳实验发现,与Sham组相比,SNI组脊髓背角兴奋性神经元的动作电位基强度明显降低(P<0.05),静息电位绝对值减小(P<0.05),并且MT2受体激动剂(8MP)可以逆转上述变化(P<0.01)。结论神经病理性痛状态下,MLT在脊髓水平显著缓解SNI小鼠的机械性痛敏,且其镇痛效应是通过MT2介导的。
Objective To study whether melatonin(MLT)is involved in the regulation of analgesic effects at the spinal cord level in neuropathic pain,and its possible receptor mechanisms.Methods Male C57BL/6 mice were used to establish a partial spared nerve injury(SNI)model and sham surgery(Sham).After 7 d,MLT and different MLT receptor agonists and/or antagonists were administered intrathecally,respectively.Von Frey filament test was used to compare the changes in paw withdrawal mechanical threshold of mice before and after SNI modeling and Sham surgery administration.Male C57BL/6 and transgenic mice were used as the research objects,and immunofluorescence staining technology was used to determine the expression of MLT receptors on different types of spinal dorsal horn neurons.Patch clamp technique was used to compare the changes in excitability of spinal dorsal horn neurons before and after SNI modeling and Sham surgery drug intervention.Results Compared with Sham group,the mechanical pain threshold in SNI group was significantly reduced(P<0.05).Intrathecal administration of MLT and Ramelteon(MT1/MT2 receptor agonist)could significantly restore the mechanical pain threshold of SNI group mice(P<0.05),but the mechanical pain threshold of SNI group mice did not recover after the administration of Ramelteon+4PP(MT2 receptor antagonist).The immunofluorescence results indicated that MT2 was widely distributed in excitatory neurons in spinal dorsal horn in mice.The patch clamp experiment found that,compared with Sham group,the action potential rheobase of excitatory neurons in spinal dorsal horn in SNI group was significantly reduced(P<0.05),the absolute value of resting potential was reduced(P<0.05),and MT2 receptor agonist(8MP)could reverse the above changes(P<0.01).Conclusion Under neuropathic pain conditions,MLT significantly alleviates mechanical hypersensitivity in SNI mice at the spinal cord level,and its analgesic effect is mediated by MT2.
作者
杨银娟
谭朝阳
王健
贾竞晨
叶晓龙
陈涛
YANG Yinjuan;TAN Chaoyang;WANG Jian;JIA Jingchen;YE Xiaolong;CHEN Tao(Department of Human Anatomy,Histology and Embryology,School of Basic Medical Sciences,Air Force Medical University,Xi'an 710032,China;No.1 Cadet Regiment,School of Basic Medical Sciences,Air Force Medical University,Xi'an 710032,China;Teaching Evaluation Center,Air Force Medical University,Xi'an 710032,China)
出处
《空军军医大学学报》
CAS
2024年第8期907-912,共6页
Journal of Air Force Medical University
基金
国家自然科学基金(32192410,32071000)。
