The effect of Mg‑2Zn‑0.5Nd alloy on the mTOR signalling pathway in L6 cells.

Magnesium alloys have shown potential as biodegradable metallic materials for orthopaedic applications due to their degradability, and their resemblance to cortical bone and biocompatible degradation/corrosion products. However, the fast corrosion rate and the potential toxicity of their alloying element has limited the clinical application of Mg alloys. In the present study, a novel Mg-2Zn-0.5Nd alloy was prepared, and then the effects on the cell biological behaviour of the Mg-2Zn-0.5Nd alloy was compared with 317L stainless steel and titanium (Ti-6Al-4V) alloys as controls. The L6 cells were cultured in various leaching solutions. The proliferative effect of the Mg-2Zn-0.5Nd alloy was determined using the Cell Counting Kit-8 assay method on the L6 cells. Also, the regulation of key intracellular signalling proteins was investigated in the L6 cells by the western blot analysis. The Mg-2Zn-0.5Nd alloy showed no cytotoxicity and induced higher levels of proliferation in the myoblast cell line L6 than the other alloys. Molecular analysis demonstrated that Mg-2Zn-0.5Nd had stimulatory effects on bone morphogenetic protein-2 phosphorylation and on the activity of phosphorylated-mammalian target of the rapamycin (mTOR), protein kinase B and forkhead box protein O1. Mg-2Zn-0.5Nd also had no effect on P38 activity. These results suggested that Mg-2Zn-0.5Nd is likely to promote myoblast cell proliferation by activating the mTOR signalling pathway.