Spatiotemporal CCR1, CCL3(MIP-1α), CXCR4, CXCL12(SDF-1α) expression patterns in a rat spinal cord injury model of posttraumatic neuropathic pain
Spatiotemporal CCR1, CCL3(MIP-1α), CXCR4, CXCL12(SDF-1α) expression patterns in a rat spinal cord injury model of posttraumatic neuropathic pain
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DOI：
10.3171/2010.12.spine10480
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发表时间：
2011-05-01
影响因子：
2.8
通讯作者：
Held-Feindt, Janka
中科院分区：
文献类型：
--
作者：
Knerlich-Lukoschus, Friederike;von der Ropp-Brenner, Beata;Held-Feindt, Janka
Object.中枢神经性疼痛是脊髓损伤（SC）后常见的具有挑战性的并发症，具体的治疗方法仍然难以捉摸。本研究的目的是通过分析大鼠创伤后神经病理性疼痛的实验性SCI范例中重要趋化因子的详细表达谱来识别这些疼痛综合征的潜在关键介质。在标准化SCI后，研究CCR 1、CCL 3（MIP-1 α）、CXCR 4和CXCL 12（SDF-1 α）的表达，同时进行机械和热伤害性阈值的行为测试;通过Infinite Horizon Impactor在T-9水平施加100 kdyn（中度损伤）和200 kdyn（重度损伤）力定义的胸脊髓挫伤损伤。假手术对照组接受椎板切除术。SCI后，通过标准化行为测试每周监测后肢运动功能以及机械和热敏感性。在SCI后早期（术后7天）和晚期（术后42天）通过实时逆转录聚合酶链反应分析趋化因子表达，并在损伤后2、7、14和42天进行免疫组织化学分析（解剖和定量）。用细胞标记物和疼痛相关肽（P物质和CGRP）或受体（TRPV-1、TRPV-2、VRL-1和TLR-4）进行双重染色。根据行为学测试获得的数据，定量的免疫组织化学趋化因子表达与SCI后6周的机械和热敏感性阈值相关。200 kdyn损伤后，动物表现出长期的伤害性阈值降低，而100 kdyn组仅在SCI后早期表现出疼痛相关行为。所研究的趋化因子在SC 1后被广泛诱导，涉及颈、胸和腰段脊髓水平，远远超出病变核心。CCR 1和CCL 3在损伤后2天在脊髓背角显著诱导，并在SCI后保持在高水平，200 kdyn挫伤后的强度显著高于100 kdyn挫伤后的强度。CXCR 4和CXCL 12水平在中度和重度病变后2 - 42天持续升高。此外，趋化因子在背柱中显著诱导，在200 kdyn损伤后42天具有最高密度水平。在背角，CCR 1与TRPV-1共表达，而CXCR 4和CXCL 12与P物质和CGRP部分共表达。CCL 3/CCR 1与GFAP、TRPV-2、TRPV-1、TLR-4共标记，CXCR 4/CXCL 12与GFAP、CD 68/ED 1、TLR 4共表达。趋化因子免疫反应密度水平，尤其是CCL 3及其受体，与伤害性感受阈值部分显著相关。作者报道了在大鼠创伤性SCI的临床相关模型中，脊髓挫伤损伤后疼痛处理脊髓区域中不同趋化因子/趋化因子受体的损伤等级依赖性上调。延长的趋化因子诱导进一步与严重SCI后延迟时间过程中的低于水平的疼痛发展相关，并与疼痛相关肽和受体共表达，表明趋化因子在SCI后的慢性中枢疼痛机制中起关键作用。(DOI：10.3171/2010.12.SPINE10480）
Object. Central neuropathic pain is a frequent challenging complication after spinal cord injury (SC), and specific therapeutic approaches remain elusive. The purpose of the present investigations was to identify potential key mediators of these pain syndromes by analyzing detailed expression profiles of important chemokines in an experimental SCI paradigm of posttraumatic neuropathic pain in rats.Methods. Expression of CCR1, CCL3(MIP-1 alpha), CXCR4, and CXCL12(SDF-1 alpha) was investigated in parallel with behavioral testing for mechanical and thermal nociceptive thresholds after standardized SCI; 100-kdyn (moderate injury) and 200-kdyn (severe injury) force-defined thoracic spinal cord contusion lesions were applied via an Infinite Horizon Impactor at the T-9 level. Sham controls received laminectomies. Hindlimb locomotor function as well as mechanical and thermal sensitivities were monitored weekly by standardized behavioral testing after SCI. Chemokine expression was analyzed by real-time reverse transcriptase polymerase chain reaction in the early (7 days postoperatively) and late (42 days postoperatively) time courses after SCI, and immunohistochemical analysis (anatomical and quantitative) was performed 2, 7, 14, and 42 days after lesioning. Double staining with cellular markers and pain-related peptides (substance P and CGRP) or receptors (TRPV-1, TRPV-2, VRL-1, and TLR-4) was performed. Based on data obtained from behavioral testing, quantified immunohistochemical chemokine expressions in individual animals were correlated with the respective mechanical and thermal sensitivity thresholds 6 weeks after SCI.Results. After 200-kdyn lesions, the animals exhibited prolonged reduction in their nociceptive thresholds, while 100-kdyn groups showed pain-related behaviors only in the early time course after SCI. Investigated chemokines were widely induced after SC!, involving cervical, thoracic, and lumbar spinal cord levels far beyond the lesion core. CCR1 and CCL3 were induced significantly in the dorsal horns 2 days after lesioning and remained at high levels after SCI with significantly higher intensities after 200-kdyn than 100-kdyn contusions. CXCR4 and CXCL12 levels continuously increased from 2 to 42 days after moderate and severe lesions. Additionally, chemokines were induced significantly in dorsal columns, with highest density levels 42 days after 200-kdyn lesions. In dorsal horns, CCR1 was coexpressed with TRPV-1 while CXCR4 and CXCL12 were partially coexpressed with substance P and CGRP. In dorsal columns, CCL3/CCR1 colabeled with GFAP, TRPV-2, TRPV-1, TLR-4; CXCR4/CXCL12 coexpressed with GFAP, CD68/ED1, and TLR4. Chemokine immunoreactivity density levels, especially CCL3 and its receptor, correlated in part significantly with nociceptive thresholds.Conclusions. The authors report lesion grade dependent upregulation of different chemokines/chemokine receptors after spinal cord contusion lesions in pain-processing spinal cord regions in a clinically relevant model of traumatic SCI in rats. Prolonged chemokine induction further correlated with below-level pain development in the delayed time course after severe SCI and was coexpressed with pain-associated peptides and receptors, suggesting that chemokines play a crucial role in chronic central pain mechanisms after SCI. (DOI: 10.3171/2010.12.SPINE10480)