Magnesium and osteoarthritis: from a new perspective

Magnesium (Mg) as an essential trace element in bone metabolism has been paid to great attention in recent years according to its osteogenic effect and critical role in bone mineralization process. However, the biological influence of Mg to cartilage metabolism had not been taken in consideration seriously, because articular cartilage is believed to be lacking of mineral ingredient, and most body Mg content is stored in bone (50–60%) and soft tissue (40%) rather than in cartilage. In this review, we retrospect the original works which previously detected Mg based calcium (Ca)-phosphate composites in cartilage tissue, and analyzed the correlation between mineral crystals and arthropathy in osteoarthritis (OA). It indicates that Mg deficiency in cartilage tissue lead to chondrocytes lesions caused by uncontrolled growing of high Ca content crystals in cartilage tissue. Additionally, Mg ions directly promote chondrocytes differentiation and viability, however, the mechanism is not understood yet. We make hypothesis and probable explanation for Mg ions’ exotic characters in chondrogenic effect based on the existent incomplete studies of Mg ions in cell energy metabolism, cytoskeletal rearrangement and integrin deformation. Mg has already been applied into the OA treatment in animal model due to its significantly protective effect on cartilage tissue. In future studies, clinical administration of Mg (oral administration or local infiltration) will be a promising therapy that conservatively treats OA with a thorough understanding of mechanism of Mg ions’ biological effect on cartilage tissue repair.