Ishii Yoshimasa, Thomas Ashby O, Guo X Edward, Hung Clark T, Chen Faye H
Department of Orthopaedic Surgery, Columbia University, New York, NY, USA.
Spine (Phila Pa 1976). 2006 Jun 15;31(14):1539-46. doi: 10.1097/01.brs.0000221994.61882.4a.
Whole rat intervertebral disc (IVD), as well as the anulus fibrosus (AF) and the nucleus pulposus (NP) were studied using immunoblot, immunohistochemistry, and reverse-transcription followed by polymerase chain reaction (RT-PCR) methods to investigate the expression and distribution of cartilage oligomeric matrix protein (COMP).
To investigate the expression and distribution patterns of COMP in normal IVD.
COMP is an extracellular matrix protein abundantly expressed in articular and growth plate cartilage, as well as bone, ligament, tendon, and synovium. The potential importance of COMP to the spine has been underscored by its mutations that lead to skeletal dysplasia with characteristic platyspondyly. However, the expression and distribution of COMP in spine and IVD has not been illustrated before.
The presence of COMP protein was investigated by immunoblotting using a COMP antibody F8 on protein extractions from whole IVD and AF or NP. To compare the expression levels of COMP between lumbar and tail IVDs, and between AF and NP of the IVD, wet weight of the tissues were used for normalization. To show that COMP can be made by IVD cells in situ, RT-PCR was used to investigate the COMP mRNA message. The distribution patterns of COMP in IVD were investigated using immunohistochemistry studies with COMP antibody F8.
COMP is expressed at both the protein and mRNA levels in both the AF and NP of both the lumbar spine and tail IVD. Immunohistochemistry studies show that COMP is found in the extracellular matrix of the IVD, exhibiting lamellar distribution pattern in the AF region. When normalized to wet weight, COMP is found to be expressed at higher levels in the lumbar than the tail IVD, and within the IVD, greater in the AF than the NP region.
Our results demonstrate the expression of COMP in both the AF and NP of the IVD. COMP is a component of the extracellular matrix of AF and NP, with a lamellar distribution pattern in the AF. Our data suggest that COMP may play a role in the normal structure of IVD.
采用免疫印迹法、免疫组织化学法以及逆转录聚合酶链反应（RT-PCR）方法，对完整大鼠椎间盘（IVD）、纤维环（AF）和髓核（NP）进行研究，以探究软骨寡聚基质蛋白（COMP）的表达及分布情况。
研究COMP在正常IVD中的表达及分布模式。
COMP是一种细胞外基质蛋白，在关节软骨、生长板软骨以及骨骼、韧带、肌腱和滑膜中大量表达。导致特征性扁平脊柱的骨骼发育异常的COMP突变，凸显了COMP对脊柱的潜在重要性。然而，此前尚未阐明COMP在脊柱和IVD中的表达及分布情况。
使用COMP抗体F8对完整IVD、AF或NP的蛋白提取物进行免疫印迹，以检测COMP蛋白的存在。为比较腰椎和尾椎IVD之间以及IVD的AF和NP之间COMP的表达水平，采用组织湿重进行标准化。为证明IVD细胞可原位合成COMP，采用RT-PCR检测COMP mRNA信息。使用COMP抗体F8进行免疫组织化学研究，以探究COMP在IVD中的分布模式。
腰椎和尾椎IVD的AF和NP中，COMP在蛋白和mRNA水平均有表达。免疫组织化学研究显示，COMP存在于IVD的细胞外基质中，在AF区域呈层状分布模式。以湿重标准化后，发现COMP在腰椎IVD中的表达水平高于尾椎IVD，且在IVD内，AF中的表达高于NP区域。
我们的结果表明COMP在IVD的AF和NP中均有表达。COMP是AF和NP细胞外基质的组成成分，在AF中呈层状分布模式。我们的数据表明COMP可能在IVD的正常结构中发挥作用。
