Sabsovich Ilya, Wei Tzuping, Guo Tian-Zhi, Zhao Rong, Shi Xiaoyou, Li Xiangqi, Yeomans David C, Klyukinov Mikhail, Kingery Wade S, Clark David J
Physical Medicine and Rehabilitation Service, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, USA Department of Anesthesiology (112A), Veterans Affairs Palo Alto Health Care System, 3801 Miranda Ave., Palo Alto, CA 94304, USA Department of Anesthesia, Stanford University School of Medicine, Stanford, CA 94305, USA Department of Orthopedic Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA.
Pain. 2008 Aug 15;138(1):47-60. doi: 10.1016/j.pain.2007.11.004. Epub 2008 Feb 20.
Tibia fracture in rats evokes chronic hindpaw warmth, edema, allodynia, and regional osteopenia resembling the clinical characteristics of patients with complex regional pain syndrome type I (CRPS I). Nerve growth factor (NGF) has been shown to support nociceptive and other types of changes found in neuropathic pain models. We hypothesized that anti-NGF antibodies might reduce one or more of the CRPS I-like features of the rat fracture model. For our studies one distal tibia of each experimental rat was fractured and casted for 4 weeks. The rats were injected with anti-NGF or vehicle at days 17 and 24 post-fracture. Nociceptive testing as well as assessment of edema and hindpaw warmth were followed during this period. Molecular and biochemical techniques were used to follow cytokine, NGF and neuropeptide levels in hindpaw skin and sciatic nerves. Lumbar spinal cord Fos immunostaining was performed. Bone microarchitecture was measured using microcomputed tomography (microCT). We found that tibia fracture upregulated NGF expression in hindpaw skin and tibia bone along with sciatic nerve neuropeptide content. We also found nociceptive sensitization, enhanced spinal cord Fos expression, osteopenia and enhanced cytokine content of hindpaw skin on the side of the fracture. Anti-NGF treatment reduced neuropeptide levels in sciatic nerve and reduced nociceptive sensitization. There was less spinal cord Fos expression and bone loss in the anti-NGF treated animals. Conversely, anti-NGF did not decrease hindpaw edema, warmth or cytokine production. Collectively, anti-NGF reduced some but not all signs characteristic of CRPS illustrating the complexity of CRPS pathogenesis and NGF signaling.
大鼠胫骨骨折会引发慢性后爪发热、水肿、痛觉过敏和局部骨质减少,类似于I型复杂性区域疼痛综合征(CRPS I)患者的临床特征。神经生长因子(NGF)已被证明可支持在神经性疼痛模型中发现的伤害性感受及其他类型的变化。我们假设抗NGF抗体可能会减轻大鼠骨折模型中一种或多种CRPS I样特征。在我们的研究中,将每只实验大鼠的一侧胫骨远端骨折并固定4周。在骨折后第17天和第24天给大鼠注射抗NGF或赋形剂。在此期间进行伤害性感受测试以及水肿和后爪发热评估。使用分子和生化技术追踪后爪皮肤和坐骨神经中的细胞因子、NGF和神经肽水平。进行腰椎脊髓Fos免疫染色。使用微型计算机断层扫描(microCT)测量骨微结构。我们发现胫骨骨折会上调后爪皮肤和胫骨骨中NGF的表达以及坐骨神经神经肽含量。我们还发现骨折侧存在伤害性感受敏化、脊髓Fos表达增强、骨质减少和后爪皮肤细胞因子含量增加。抗NGF治疗降低了坐骨神经中的神经肽水平并减轻了伤害性感受敏化。抗NGF治疗的动物脊髓Fos表达减少且骨质流失减少。相反,抗NGF并未减轻后爪水肿、发热或细胞因子产生。总体而言,抗NGF减轻了CRPS的一些但并非全部特征,说明了CRPS发病机制和NGF信号传导的复杂性。