Biodegradable magnesium-based alloy skull repairment (MASR) for skull bone defect: In vitro and in vivo evaluation

Over the last decade, due to the disadvantages of conventional implant materials in skull bone defects, there has been a high demand for alternative biodegradable materials. As a typical biodegradable metal, magnesium (Mg) and its alloy have been successfully researched in various fields and applied in clinical in recent years, but none of them are about osteointegration, especially in cranioplasty. This study aims to explore the effect of Mg-based alloy skull repairment (MASR) on bone healing for the first time. The results verify that the high pure magnesium (HPM) and Mg-2 wt% Zn alloys can promote skull bone repair and induce the M2-like polarization of macrophages. Meanwhile, we also confirmed the pro-osteogenic function of induced M2-like macrophages on the bone marrow stem cells. Moreover, due to the close interaction of MASR and intracranial microenvironment, we clarified its immune regulatory function and underlying mechanisms on the microglia. The Mg-2Zn alloy presented a lower degradation rate, greater mechanical strength, and less influence on bone structure, and the MASR may serve as a potential clinical approach.