Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, 801 South Paulina Street, Room 531, Chicago, IL, 60612, USA.
Department of Restorative Dentistry, Passo Fundo Dental School, University of Passo Fundo, UPF, Passo Fundo, RS, Brazil.
Odontology. 2019 Jul;107(3):316-323. doi: 10.1007/s10266-018-00408-0. Epub 2019 Feb 1.
Proteoglycans are biomacromolecules with significant biomineralization and structural roles in the dentin extracellular matrix. This study comprehensively assessed the mechanical properties and morphology of the dentin extracellular matrix following chemical removal of proteoglycans to elucidate the structural roles of proteoglycans in dentin. Dentin extracellular matrix was prepared from extracted teeth after complete tissue demineralization. Chemical removal of proteoglycans was carried-out using guanidine hydrochloride for up to 10 days. The removal of proteoglycans was determined by dimethylmethylene blue colorimetric assay and histological staining analyses using transmission electron microscopy and optical microscopy. The modulus of elasticity of dentin matrix was determined by a 3-point bending test method. Partial removal of proteoglycans induced significant modifications to the dentin matrix, particularly to type I collagen. Removal of proteoglycans significantly decreased the modulus of elasticity of dentin extracellular matrix (p < 0.0001). In conclusion, the subtle disruption of proteoglycans induces pronounced changes to the collagen network packing and the bulk modulus of elasticity of dentin matrix.
蛋白聚糖是具有重要生物矿化和结构作用的生物大分子，存在于牙本质细胞外基质中。本研究通过化学去除蛋白聚糖，全面评估牙本质细胞外基质的力学性能和形态，以阐明蛋白聚糖在牙本质中的结构作用。牙本质细胞外基质是从完全脱矿的牙齿中提取的。使用盐酸胍对蛋白聚糖进行化学去除，时间长达 10 天。通过二甲亚甲基蓝比色法和使用透射电子显微镜和光学显微镜的组织染色分析来确定蛋白聚糖的去除情况。通过三点弯曲试验方法测定牙本质基质的弹性模量。部分去除蛋白聚糖会显著改变牙本质基质，尤其是 I 型胶原蛋白。去除蛋白聚糖会显著降低牙本质细胞外基质的弹性模量（p < 0.0001）。总之，蛋白聚糖的细微破坏会引起牙本质基质中胶原蛋白网络堆积和体积弹性模量的明显变化。
