Annulus Fibrosus Cells Interact With Neuron-Like Cells to Modulate Production of Growth Factors and Cytokines in Symptomatic Disc Degeneration
Annulus Fibrosus Cells Interact With Neuron-Like Cells to Modulate Production of Growth Factors and Cytokines in Symptomatic Disc Degeneration
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DOI：
10.1097/brs.0b013e31820cd2d8
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发表时间：
2012-01-01
期刊：
影响因子：
3
通讯作者：
Park, Youn-Kwan
中科院分区：
文献类型：
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作者：
Moon, Hong Joo;Kim, Joo Han;Park, Youn-Kwan
研究设计.我们假设纤维环损伤时AF/神经元的相互作用参与了新血管形成和神经长入，这是症状性椎间盘退变的病理标志。使用体外模型鉴定与AF/神经元相互作用相关的生长因子和炎性细胞因子。椎间盘源性疼痛是由外侧纤维环（AF）撕裂引起的慢性顽固性疼痛;这是一种独特的结构，在外侧三分之一处有游离神经末梢，位于背根神经节旁边。纤维环损伤中AF与神经元细胞的关系尚未得到广泛研究。将人AF细胞与视黄酸（RA）处理的SH-SY 5 Y人神经母细胞瘤细胞系（神经元样细胞）共培养。使用酶联免疫吸附测定法测定来自单独培养或共培养的细胞的条件培养基的生长因子和炎性细胞因子。使用相同的结果测量方法比较神经元样细胞、AF细胞和共培养组对IL-1 β/TNF-α的反应。RA处理的SH-SY 5 Y细胞在第7天显示出显著的神经突生长;这是神经元样细胞的典型形态学发现。神经元样细胞在基础条件下产生血管内皮生长因子（VEGF）和IGF-1，并响应TNF-α以剂量依赖性方式分泌少量IL-8。共培养增强了VEGF、TGF-β 1和β-NGF的分泌，并抑制了IGF-1的产生。IL-1 β/TNF-α刺激可下调共培养组和AF细胞的VEGF表达。IL-1 β/TNF-α刺激增强AF细胞产生大量IL-6和IL-8; IL-1 β产生的反应大于TNF-α。神经元样细胞不产生IL-6和IL-8。这些研究表明，AF细胞参与炎症反应，并且AF和神经元样细胞之间的相互作用增强了负责新血管形成和神经向内生长的生长因子的产生。AF损伤有可能通过AF和神经组织的相互作用引发新血管形成/神经长入和炎症反应。
Study Design. We hypothesized that AF/neuron interactions during annular injury were involved in neovascularization and nerve ingrowth, the pathologic hallmarks of symptomatic disc degeneration.Objective. To identify growth factors and inflammatory cytokines related to AF/neuron interactions using in vitro model.Summary of Background Data. Discogenic pain is the chronic intractable pain initiated by tears in the outer annulus fibrosus (AF); this is a unique structure with free nerve endings at outer one-third, located beside dorsal root ganglia. The relationship between AF and neuron cells in annular injury has not been extensively investigated.Methods. Human AF cells were cocultured with a retinoic acid (RA)-treated SH-SY5Y human neuroblastoma cell line (neuron-like cells). Conditioned media from cells cultured alone or in coculture were assayed for growth factors and inflammatory cytokines using enzyme-linked immunosorbent assays. The responses of the neuron-like cells, the AF cells, and the cocultured group to IL-1 beta/TNF-alpha were compared using the same outcome measures.Results. RA-treated SH-SY5Y cells showed significant neurite outgrowth on the 7th day; this is a typical morphologic finding of neuron-like cells. Neuron-like cells produced vascular endothelial growth factor (VEGF) and IGF-1 under basal conditions and dose-dependently secreted small amounts of IL-8 in response to TNF-alpha. Coculturing enhanced the secretion of VEGF, TGF-beta 1, and beta-NGF, and suppressed the production of IGF-1. VEGF in the coculture group and the AF cells was downregulated by IL-1 beta/TNF-alpha stimulation. IL-1 beta/TNF-alpha stimulation enhanced the production of large amounts of IL-6 and IL-8 from AF cells; IL-1 beta produced a greater response than TNF-alpha. The neuron-like cells did not produce detectable amounts of IL-6 or IL-8.Conclusion. These studies suggest that AF cells are involved in an inflammatory reaction and that the interactions between AF and neuron-like cells enhance the production of growth factors responsible for neovascularization and nerve ingrowth. AF injury has the potential to initiate neovascularization/nerve ingrowth and an inflammatory reaction through the interactions of AF and neural tissues.