A novel glucosamine derivative with low cytotoxicity enhances chondrogenic differentiation of ATDC5.

Glucosamine (GlcN) is a component of native cartilage extracellular matrix and useful in cartilage repair, but it was limited by toxicity in high concentrations. With the aim of altering bioactive properties of GlcN to reduce the toxicity and to facilitate chondrogenesis for hyaline cartilage formation, we introduced an amino-group modification with double bond into GlcN to produce N-acryloyl-glucosamine (AGA). The cell ATDC5 was chosen to evaluate its cytotoxicity and chondrogenesis capability. Cell proliferation and cytotoxicity assay showed that AGA had significantly reduced the cytotoxicity compared to GlcN, and promoted ATDC5 proliferation. Alcian blue staining and biochemical analysis indicated that AGA enhanced extracellular matrix deposition. Both the mRNA and protein levels of articular cartilage markers, like Collagen II and Aggrecan were up-regulated, as shown by quantitative real-time PCR and immunofluorescence staining. Moreover, the level of fibrocartilage marker Collagen I and hypertrophic marker Collagen Χ weren't significantly changed. Overall, these results demonstrated that the AGA achieved the functional double-bond, reduction in toxicity and enhancement in chondrogenesis could be more potential in cartilage repair.

Glucosamine-modified polyethylene glycol hydrogel-mediated chondrogenic differentiation of human mesenchymal stem cells.

Glucosamine (GA) is an important cartilage matrix precursor for the glycosaminoglycan biochemical synthesis, and has positive effects on cartilage regeneration, particularly in osteoarthritis therapy. However, it has not been used as a bioactive group in scaffolds for cartilage repair widely. In this study, we synthesized modified polyethylene glycol (PEG) hydrogel with glucosamine and then encapsulated human bone mesenchymal stem cells (hBMSCs) in the hydrogel to induce the differentiation of hBMSCs into chondrocytes in three-dimensional culture. The GA-modified PEG hydrogels promoted the chondrogenesis of hBMSCs, particularly in the concentration of 5mM and 10mM. The subcutaneous transplantation of 10mM GA-modified hydrogels with hBMSCs formed cartilage-like blocks in vivo for 8weeks. Importantly, with glucosamine increase, the modified hydrogels down-regulated the fibrosis and hypertrophic cartilage markers in protein level. Therefore, glucosamine modified PEG hydrogels facilitated the chondrogenesis of hBMSCs, which might represent a new method for cartilage repair using a tissue-engineering approach.