Cellular response of chondrocytes to magnesium alloys for orthopedic applications

In the present study, the effects of Mg-Nd-Zn-Zr (JDBM), brushite (CaHPO4·2H2O)-coated JDBM (C-JDBM), AZ31, WE43, pure magnesium (Mg) and Ti alloy (TC4) on rabbit chondrocytes were investigated in vitro. Adhesion experiments revealed the satisfactory morphology of chondrocytes on the surface of all samples. An indirect cytotoxicity test using MTT assay revealed that C‑JDBM and TC4 exhibited results similar to those of the negative control, better than those obtained with JDBM, AZ31, WE43 and pure Mg (p<0.05). There were no statistically significant differences observed between the JDBM, AZ31, WE43 and pure Mg group (p>0.05). The results of indirect cell cytotoxicity and proliferation assays, as well as those of apoptosis assay, glycosaminoglycan (GAG) quantification, assessment of collagen Ⅱ (Col Ⅱ) levels and RT-qPCR revealed a similar a trend as was observed with MTT assay. These findings suggested that the JDBM alloy was highly biocompatible with chondrocytes in vitro, yielding results similar to those of AZ31, WE43 and pure Mg. Furthermore, CaHPO4·2H2O coating significantly improved the biocompatibility of this alloy.