Department of Bioengineering, University of Utah, United States.
Matrix Biol. 2013 Oct-Nov;32(7-8):414-23. doi: 10.1016/j.matbio.2013.04.004. Epub 2013 Apr 20.
The proteoglycan decorin is known to affect both the fibrillogenesis and the resulting ultrastructure of in vitro polymerized collagen gels. However, little is known about its effects on mechanical properties. In this study, 3D collagen gels were polymerized into tensile test specimens in the presence of decorin proteoglycan, decorin core protein, or dermatan sulfate (DS). Collagen fibrillogenesis, ultrastructure, and mechanical properties were then quantified using a turbidity assay, 2 forms of microscopy (SEM and confocal), and tensile testing. The presence of decorin proteoglycan or core protein decreased the rate and ultimate turbidity during fibrillogenesis and decreased the number of fibril aggregates (fibers) compared to control gels. The addition of decorin and core protein increased the linear modulus by a factor of 2 compared to controls, while the addition of DS reduced the linear modulus by a factor of 3. Adding decorin after fibrillogenesis had no effect, suggesting that decorin must be present during fibrillogenesis to increase the mechanical properties of the resulting gels. These results show that the inclusion of decorin proteoglycan during fibrillogenesis of type I collagen increases the modulus and tensile strength of resulting collagen gels. The increase in mechanical properties when polymerization occurs in the presence of the decorin proteoglycan is due to a reduction in the aggregation of fibrils into larger order structures such as fibers and fiber bundles.
蛋白聚糖decorin 已知可影响体外聚合胶原凝胶的原纤维形成和最终超微结构。然而，关于其对机械性能的影响知之甚少。在这项研究中，decorin 蛋白聚糖、decorin 核心蛋白或硫酸皮肤素（DS）存在的情况下，将 3D 胶原凝胶聚合到拉伸试验样品中。然后使用浊度测定法、2 种形式的显微镜（SEM 和共聚焦）和拉伸试验来定量胶原原纤维形成、超微结构和机械性能。与对照凝胶相比，decorin 蛋白聚糖或核心蛋白的存在降低了原纤维形成过程中的速率和最终浊度，并减少了纤维聚集（纤维）的数量。与对照相比，添加 decorin 和核心蛋白将线性模量提高了 2 倍，而添加 DS 将线性模量降低了 3 倍。在原纤维形成后添加 decorin 没有效果，这表明 decorin 必须在原纤维形成过程中存在才能提高所得凝胶的机械性能。这些结果表明，在 I 型胶原的原纤维形成过程中包含 decorin 蛋白聚糖会增加所得胶原凝胶的模量和拉伸强度。在存在 decorin 蛋白聚糖的情况下聚合时，机械性能的增加是由于纤维和纤维束等较大有序结构中纤维的聚集减少所致。
