title: In vivo assessment of the host reactions to the biodegradation of the two novel magnesium alloys ZEK100 and AX30 in an animal model.
abstract: BACKGROUND
  Most studies on biodegradable magnesium implants published recently use magnesium-calcium-alloys or magnesium-aluminum-rare earth-alloys.However, since rare earths are a mixture of elements and their toxicity is unclear, a reduced content of rare earths is favorable. The present study assesses the in vivo biocompatibility of two new magnesium alloys which have a reduced content (ZEK100) or contain no rare earths at all (AX30).
  
  
  METHODS
  24 rabbits were randomized into 4 groups (AX30 or ZEK100, 3 or 6 months, respectively) and cylindrical pins were inserted in their tibiae. To assess the biodegradation μCT scans and histological examinations were performed.
  
  
  RESULTS
  The μCT scans showed that until month three ZEK100 degrades faster than AX30, but this difference is leveled out after 6 months. Histology revealed that both materials induce adverse host reactions and high numbers of osteoclasts in the recipient bone. The mineral apposition rates of both materials groups were high.
  
  
  CONCLUSIONS
  Both alloys display favorable degradation characteristics, but they induce adverse host reactions, namely an osteoclast-driven resorption of bone and a subsequent periosteal formation of new bone. Therefore, the biocompatibility of ZEK100 and AX30 is questionable and further studies, which should focus on the interactions on cellular level, are needed.
authors.affiliation: School of Veterinary Medicine Hanover, Small Animals Clinic, CRC 599, Bünteweg 9, 30559 Hanover, Germany.
authors.forename: Tim Andreas
authors.initials: TA
authors.lastname: Huehnerschulte
authors.forename: Janin
authors.initials: J
authors.lastname: Reifenrath
authors.forename: Brigitte
authors.initials: B
authors.lastname: von Rechenberg
authors.forename: Dina
authors.initials: D
authors.lastname: Dziuba
authors.forename: Jan Marten
authors.initials: JM
authors.lastname: Seitz
authors.forename: Dirk
authors.initials: D
authors.lastname: Bormann
authors.forename: Henning
authors.initials: H
authors.lastname: Windhagen
authors.forename: Andrea
authors.initials: A
authors.lastname: Meyer-Lindenberg
mesh_terms: D000497:Alloys / Q000378:metabolism* / Q000633:toxicity*; D000818:Animals; D001853:Bone Marrow / Q000000981:diagnostic imaging / Q000187:drug effects / Q000378:metabolism; D008274:Magnesium / Q000378:metabolism* / Q000633:toxicity*; D008422:Materials Testing / Q000379:methods*; D008903:Minerals / Q000378:metabolism; D023421:Models, Animal; D019736:Prostheses and Implants / Q000009:adverse effects; D011817:Rabbits; D013194:Staining and Labeling; D014048:Tolonium Chloride / Q000378:metabolism; D055114:X-Ray Microtomography
chemical_list: D000497:Alloys; D008903:Minerals; D014048:Tolonium Chloride; D008274:Magnesium