Structural and biomechanical changes to dentin extracellular matrix following chemical removal of proteoglycans
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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.
KeywordsProteoglycans Collagen Dentin Modulus of elasticity Histology
The study was supported by the National Institute of Health—NIH/NIDCR (#DE021040) and CAPES Foundation-Brazil (#BEX 17764/12-2). The authors would like to thank Ariene Leme-Kraus for the support with the statistical analysis.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
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