| 摘要: |
| 目的 探讨右美托咪定（Dex）对吗啡戒断反应中痛觉过敏的影响及机制。方法 根据药物处理不同将健康雄性C57/BL小鼠随机分为空白对照组、吗啡戒断反应痛觉过敏模型组（M组）、M＋Dex组、M＋米诺环素（Min）组、M＋Dex＋Min组、M＋MK8825组、M＋Min＋MK8825组，每组6只。空白对照组小鼠不予任何干预；其他6组小鼠每天上午8：00和下午6：00各腹腔注射吗啡溶液1次，连续注射6 d，随后注射纳洛酮构建吗啡戒断反应痛觉过敏模型。M组为单纯吗啡戒断反应痛觉过敏小鼠，M＋Dex、M＋Min、M＋Dex＋Min、M＋MK8825、M＋Min＋MK8825组小鼠在纳洛酮给药前30 min通过鞘内导管分别单次给予人工脑脊液稀释的Dex、小胶质细胞激活抑制剂Min、Dex与Min混合液、降钙素基因相关肽（CGRP）抑制剂MK8825、Min与MK8825混合液。应用von Frey纤维丝测定各组小鼠机械性痛阈，免疫荧光和蛋白质印迹法检测脊髓背角小胶质细胞激活标志物钙离子结合调节因子1（IBA-1）的表达，蛋白质免疫印迹法和PCR检测脊髓背角组织中CGRP蛋白和mRNA表达变化，并用微透析技术测定脊髓背角炎症因子TNF-α、IL-1β水平，最后电生理技术观察Dex对脊髓背角自发性抑制性突触后电流（sIPSC）的影响。结果 成功构建吗啡戒断反应痛觉过敏模型，与空白对照组相比，M组机械性痛阈降低（P＜0.05），脊髓背角IBA-1、CGRP表达及TNF-α、IL-1β水平均增加（P均＜0.05）。与M组相比，M＋Dex、M＋Min、M＋Dex＋Min组机械性痛阈均升高（P均＜0.05），脊髓背角IBA-1、CGRP表达及TNF-α、IL-1β水平均降低（P均＜0.05）。与M组相比，M＋MK8825组脊髓背角TNF-α、IL-1β水平均降低（P均＜0.05），而M＋MK8825组与M＋Min＋MK8825组之间TNF-α、IL-1β水平差异均无统计学意义（P均＞0.05）。电生理结果显示，与人工脑脊液灌流相比，灌流Dex增强了脊髓背角神经元sIPSC的振幅和频率（P均＜0.05）。结论 Dex通过抑制脊髓小胶质细胞激活、减少CGRP表达、减轻脊髓炎症反应及增强脊髓抑制性电活动缓解吗啡戒断反应中的痛觉过敏。 |
| 关键词: 右美托咪定 吗啡 痛觉过敏 小胶质细胞 降钙素基因相关肽 脊髓背角 |
| DOI：10.16781/j.CN31-2187/R.20210950 |
| 投稿时间：2021-09-22修订日期：2022-01-06 |
| 基金项目:河南省自然科学基金青年项目（222300420384），河南省医学科技攻关计划（SBGJ202003056，SBGJ202102204）． |
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| Dexmedetomidine alleviates hyperalgesia in morphine withdrawal syndrome by inhibiting microglia activation in spinal cord |
| KONG Er-liang1,2,FENG Xu-dong2,YANG Mei1,LI Yong-chang1,YUAN Hong-bin1* |
(1. Department of Anesthesiology, The Second Affiliated Hospital of Naval Medical University (Second Military Medical University), Shanghai 200003, China;
2. Department of Anesthesiology, No. 988 Hospital of Logistic Support Force of PLA, Zhengzhou 450042, Henan, China
*Corresponding author) |
| Abstract: |
| Objective To investigate the effect and mechanism of dexmedetomidine (Dex) on hyperalgesia in morphine withdrawal mice. Methods According to drug treatments, healthy male C57/BL mice were randomly divided into blank control group, morphine withdrawal hyperalgesia model group (M group), M+Dex group, M+minocycline (Min) group, M+Dex+Min group, M+MK8825 group, and M+Min+MK8825 group (n=6). No intervention was given to mice in the blank control group. The other 6 groups of mice were intraperitoneally injected with morphine twice a day at 8:00 a.m. and 6:00 p.m. for 6 consecutive days, followed by naloxone injection to establish the morphine withdrawal hyperalgesia model. The M group received no more drugs, while the M+Dex, M+Min, M+Dex+Min, M+MK8825, and M+Min+ MK8825 groups were given Dex diluted with artificial cerebrospinal fluid, microglia activation inhibitor Min, Dex and Min mixture, calcitonin gene-related peptide (CGRP) inhibitor MK8825, and Min and MK8825 mixture through intrathecal catheter 30 min before naloxone administration, respectively. Mechanical pain thresholds were tested by von Frey. The expression of microglia activation marker ionized calcium-binding adapter molecule 1 (IBA-1) in the spinal dorsal was observed by immunofluorescence and Western blotting. The expression of CGRP protein and mRNA in the spinal cord of each tissue was detected by Western blotting and polymerase chain reaction (PCR). The levels of inflammatory factors tumor necrosis factor α (TNF-α) and interleukin-1β (IL-1β) in the spinal cord were determined by microdialysis. Finally, the effect of Dex on spontaneous inhibitory postsynaptic current (sIPSC) in the spinal dorsal horn was observed by electrophysiology. Results The morphine withdrawal hyperalgesia model was successfully established. Compared with the blank control group, the mechanical pain threshold in the M group was significantly decreased (P<0.05), and the expression of IBA-1, CGRP and the levels of TNF-α and IL-1β in the spinal dorsal horn were significantly increased (all P<0.05). Compared with the M group, the pain thresholds in the M+Dex, M+Min and M+Dex+Min groups were significantly increased (all P<0.05), and the expression of IBA-1, CGRP and the levels of TNF-α and IL-1β in the spinal dorsal horn were significantly decreased (all P<0.05). The levels of TNF-α and IL-1β in spinal dorsal horn of the M+MK8825 group were significantly lower than those of the M group (both P<0.05), while there were no significant differences between the M+MK8825 group and M+Min+MK8825 group (both P>0.05). Electrophysiology results showed that Dex enhanced the amplitude and frequency of sIPSC in the spinal dorsal horn neurons compared with artificial cerebrospinal fluid perfusion (both P<0.05). Conclusion Dex relieves hyperalgesia in morphine withdrawal syndrome by inhibiting spinal microglia activation, reducing the expression of CGRP, alleviating spinal inflammatory response, and enhancing spinal inhibitory electrical activity. |
| Key words: dexmedetomidine morphine hyperalgesia microglia calcitonin gene-related peptide spinal dorsal horn |
