Department of Orthopaedic Surgery, McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, PA 19104-6081, USA.
Connect Tissue Res. 2012;53(5):343-8. doi: 10.3109/03008207.2012.654866. Epub 2012 Feb 13.
While tendons typically undergo primary tensile loading, the human supraspinatus tendon (SST) experiences substantial amounts of tension, compression, and shear in vivo. As a result, the functional roles of the extracellular matrix components, in particular the proteoglycans (PGs), are likely complex and important. The goal of this study was to determine the PG content in specific regions of the SST that exhibit differing mechanical function. The concentration of aggrecan, biglycan, and decorin was determined in six regions of the human SST using immunochemical techniques. We hypothesized that aggrecan concentrations would be highest in areas where the tendon likely experiences compression; biglycan levels would be highest in regions likely subjected to injury and/or active remodeling such as the anterior regions; decorin concentrations would be highest in regions of greatest tensile stiffness. Our results generally supported these hypotheses and demonstrated that aggrecan and biglycan share regional variability, with increased concentration in the anterior and posterior regions and smaller concentration in the medial regions. Decorin, however, was in high concentration throughout all regions. The data presented in this study represent the first regional measurements of PG in the SST. Together with our previous regional measurements of mechanical properties, these data can be used to evaluate SST structure-function relationships. With knowledge of the differences in specific PG content, their spatial variations in the SST, and their relationships to tendon mechanics, we can begin to associate defects in PG content with specific pathology, which may provide guidance for new therapeutic interventions.
虽然肌腱通常承受主要的拉伸载荷，但人体肩袖上的冈上肌腱（SST）在体内会承受大量的张力、压缩和剪切。因此，细胞外基质成分的功能作用，特别是蛋白聚糖（PGs），可能是复杂而重要的。本研究的目的是确定在具有不同机械功能的 SST 特定区域中 PG 的含量。使用免疫化学技术测定了 SST 六个区域中聚集蛋白聚糖、biglycan 和 decorin 的浓度。我们假设在肌腱可能承受压缩的区域，聚集蛋白聚糖的浓度最高；在前部区域等可能受到损伤和/或主动重塑的区域，biglycan 水平最高；在拉伸刚度最大的区域，decorin 浓度最高。我们的结果总体上支持这些假设，并表明聚集蛋白聚糖和 biglycan 具有区域变异性，在前部和后部区域的浓度增加，在中部区域的浓度减小。然而，decorin 在所有区域的浓度都很高。本研究中提供的数据代表了 SST 中 PG 的首次区域测量。结合我们之前对机械性能的区域测量，这些数据可用于评估 SST 的结构-功能关系。了解特定 PG 含量的差异、它们在 SST 中的空间变化以及它们与肌腱力学的关系，我们可以开始将 PG 含量的缺陷与特定的病理联系起来，这可能为新的治疗干预提供指导。
