小鼠背根神经节慢性压迫引起的痛敏化机制

陶金 王涛 朱杰 马超*

doi:10.16098/j.issn.0529-1356.2019.02.003

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解剖学报 ›› 2019, Vol. 50 ›› Issue (2) : 152-157. DOI: 10.16098/j.issn.0529-1356.2019.02.003

神经生物学

小鼠背根神经节慢性压迫引起的痛敏化机制

陶金¹ 王涛¹ 朱杰²马超^1*

作者信息 +

Mechanisms of pain hypersensitivity in a mouse model of chronic compression of dorsal root ganglia

TAO Jin¹WANG Tao¹ ZHU Jie²MA Chao ^1*

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文章历史 +

摘要

目的探讨背根神经节慢性压迫（CCD）引起的低剂量辣椒素诱发痛敏化机制。方法将光滑L型钢柱插入小鼠的L4椎间孔，对背根神经节（DRG）造成持续压迫，建立小鼠CCD模型。于CCD术前1 d及术后第1、3、5、7 d向小鼠胫骨前区皮下注射不同浓度的辣椒素（0.01、0.1、1 g/L）10 μl后采用行为学检测动物的痛行为学表现并录像，以寻找CCD术后辣椒素诱发痛行为差异最显著的浓度。利用Pirt-GCaMP3转基因小鼠，胫骨前区皮下注射最佳浓度辣椒素，利用激光扫描共焦显微镜在体记录DRG神经元对外周体表感受野辣椒素刺激的反应。利用免疫荧光染色技术观察正常及CCD模型压迫5 d后DRG内辣椒素受体（TRPV1）的表达变化。结果行为学检测结果显示，与正常小鼠相比，低浓度（0.1 g/L）辣椒素在CCD模型小鼠上引起的诱发痛显著提升（n=8; 术后1 d，P<0.01；术后5 d，P<0.05；术后7 d，P<0.05；术后3 d，P> 0.05）。在体激光扫描共焦成像结果表明，在记录的398（n=4）个正常小鼠L4 DRG神经元中，对皮下注射0.1 g/L辣椒素有反应的神经元为75个，在382（n=6）个CCD术后5 d的小鼠L4 DRG神经元中，对皮下注射0.1 g/L辣椒素有反应的神经元为169个，差异有显著性（P<0.01）。免疫荧光染色结果显示，在653（n=10）个正常神经元中，TRPV1阳性的细胞数为148，在611（n=6）个CCD神经元中，TRPV1阳性的细胞数为237，差异有显著性（P<0.01）。结论在小鼠CCD模型中，受到压迫DRG神经元TRPV1表达上调，导致相应的体表感受区域对辣椒素诱发痛敏化。

Abstract

Objective To investigate the mechanisms of pain hypersensitivity to lowdose capsaicin in a mouse model of chronic compression of dorsal root ganglion (CCD). Methods Chronic compression of L4 DRG was performed in mice by inserting an L-shaped stainless steel rod into the L4 intervertebral foramina. Different doses of capsaicin（0.01, 0.1, 1 g/L）1 μl were injected into the skin on the calf area and behavior responses were videotaped on pre-CCD 1 days and post-CCD 1, 3, 5, 7 days. The optimal concentration that led to a significant difference after CCD was determined and was used in the following in-vivoDRG imaging studies. Immunofluorescent staining was conducted to evaluate the expression of transient receptor potential vanilloid 1 (TRPV1) in DRG from na?ve and CCD mice. Results Behavioral tests showed that 0.1 g/L capsaicin elicits a significant difference in pain-like behaviors after CCD（n=8; post-CCD 1 day, P<0.01; post-CCD 5, 7 days P<0.01; post-CCD 3 days, P> 0.05. In vivocalcium imaging showed an enhanced number of activated DRG neurons to the injection of capsaicin in CCD mice, which was 75 in total of 398(n=4) for control mice and 169 in total of 382(n=6) (P<0.01). According to immunofluorescent staining results, there were 148 TRPV1+ neurons in total 653 counted neurons (n=10) for control mice and 237 TRPV1+ neurons in total of 611 neurons (n=6) for CCD mice (P<0.01). Conclusion Chronically compressed DRG neurons show upregulated TRPV1 receptor and enhanced responses to low-dose capsaicin, that produce pain hypersensitivity in the CCD mice.

导出引用

陶金王涛朱杰马超. 小鼠背根神经节慢性压迫引起的痛敏化机制[J]. 解剖学报. 2019, 50(2): 152-157 https://doi.org/10.16098/j.issn.0529-1356.2019.02.003

TAO Jin WANG Tao ZHU Jie MA Chao. Mechanisms of pain hypersensitivity in a mouse model of chronic compression of dorsal root ganglia [J]. Acta Anatomica Sinica. 2019, 50(2): 152-157 https://doi.org/10.16098/j.issn.0529-1356.2019.02.003

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