In vitro investigation of cellular effects of magnesium and magnesium-calcium alloy corrosion products on skeletal muscle regeneration

Biodegradable magnesium (Mg) has garnered attention for its use in orthopaedic implants due to mechanical properties that closely match to those of bone. Studies have been undertaken to understand the corrosion behaviour of these materials and their effects on bone forming cells. However, there is lack of research on how the corrosion of these biomaterials affect surrounding tissues such as skeletal muscle. Mg plays an important role in the structural and functional properties of skeletal muscle. It is therefore important to investigate the response of skeletal muscle cells to both soluble (Mg ions) and insoluble (corrosion granules) corrosion products. Through in vitro studies it is possible to observe the effects of corrosion products on myotube formation by the fusion of single muscle precursor cells known as myoblasts. To achieve this goal, it is first important to determine if these corrosion products are toxic to myotubes. Here it was noted that although there was a slight decrement in cellular viability after initial exposure, this soon recovered to control levels. A high Ca/Mg ratio resulted in the formation of large myotubes and a low Ca/Mg ratio negatively affected myotube maturation. Mg2+ and Ca2+ ions are important in the process of myogenesis, the concentration of these ions and the ratio of the ions to each other played a significant role in myotube cellular activity. The outcomes of this study could pave the way to a bio-informed and integrated approach to the design and engineering of Mg-based orthopaedic implants.