Degradations of different processed Mg alloy implants lead to distinct foreign body reactions (FBRs)

ABSTRACT: Mg alloy is one of the lightest metals on earth and has the most similar mechanical properties to human bones. However, the active chemical properties and fast in vivo degrade speed significantly hinder its further employment as human implant. In this study, three different Mg alloys are employed to investigate the in vitro corrosion behavior including weight loss, pH value evolution and surface hardness and in vivo degradable speed and tissue compatibility. All three Mg alloys are well tolerated when implanted in SD rats, with minimal influence on hepato-and renal functions and vital organs. Compared to cold extruded AZ31 (CE AZ31) and pure Mg (PM) specimens, fully annealed AZ31 (FA AZ31) presents much stable surface asperity. Proteomics analysis of tissues near implant site showed that FA AZ31 activates few inflammation and immune associated signaling pathways; while the CE AZ31 and pure Mg led more significant inflammatory responses as confirmed by the cytokine array that pure Mg stimulate higher IL-1 production than FA AZ31. Further, FA AZ31 can activate pathways of cell organization and development that may improve the recovery of the injured tissues neighboring the implant sites. Besides, all three Mg alloys cannot inhibit a methicillin-resistant S. aureus growth if the implants are contaminated with this bacterium. FA AZ31 has a higher ratio of first-order pyramidal slips system (10-11) {10-1-2} than pure Mg and cold extruded AZ31 analysed by EBSD, suggesting the process of dynamic recovery may plays an important role in the improvement of mechanical properties, especially bio-properties including corrosion resistance and biocompatibility. In conclusion, FA AZ31 has better biocompatibilities and corrosion resistance, makes it a promising candidate of metal-based degradable implant and warrant further investigation.

INSTRUMENT(S): Q Exactive HF

ORGANISM(S): Rattus Norvegicus (rat)

SUBMITTER: Tianfang Wang  

LAB HEAD: Tianfang Wang

PROVIDER: PXD028519 | Pride | 2023-01-26

REPOSITORIES: Pride