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.