title: In vivo corrosion behaviour of magnesium alloy in association with surrounding tissue response in rats.
abstract: Biodegradable magnesium (Mg) alloys are the most promising candidates for osteosynthesis devices. However, their in vivo corrosion behaviour has not been fully elucidated. The aim of this study was to clarify the influence of the physiological environment surrounding Mg alloys on their corrosion behaviour. A Mg-1.0Al alloy with a fine-grained structure was formed into plates using titanium (Ti) as a control. These plates were implanted into the subperiosteum in the head, subcutaneous tissue of the back, and in the muscle of the femur of rats for 1, 2 and 4 weeks. The volumes of the remaining Mg alloy and of the insoluble salt deposition and gas cavities around the Mg alloy were determined by microtomography, and the volume losses were calculated. Then, the tissue response around the plates in each implantation site was examined histopathologically, and its relation to the respective volume loss was analyzed. These analyses determined that the Mg alloy was corroded fastest in the head, at an intermediate level in the back, and slowest in the femur. The insoluble salt deposition at the Mg alloy surface had no influence on the volume loss. Gas cavities formed around the Mg alloy at all implantation sites and decreased after 4 weeks. Histopathological examination revealed that the Mg alloy exhibited good biocompatibility, as was seen with Ti. In addition, vascularized fibrous capsules formed around the plates and became mature with time. Notably, the volume loss in the different anatomical locations correlated with capsule thickness. Together, our results suggest that, to facilitate the successful clinical application of Mg alloys, it will be necessary to further comprehend their interactions with specific in vivo environments.
authors.affiliation: Department of Plastic and Reconstructive Surgery, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan.
authors.forename: Chieko
authors.initials: C
authors.lastname: Miura
authors.forename: Yoshinaka
authors.initials: Y
authors.lastname: Shimizu
authors.forename: Yoshimichi
authors.initials: Y
authors.lastname: Imai
authors.forename: Toshiji
authors.initials: T
authors.lastname: Mukai
authors.forename: Akiko
authors.initials: A
authors.lastname: Yamamoto
authors.forename: Yuya
authors.initials: Y
authors.lastname: Sano
authors.forename: Naoko
authors.initials: N
authors.lastname: Ikeo
authors.forename: Shuji
authors.initials: S
authors.lastname: Isozaki
authors.forename: Toru
authors.initials: T
authors.lastname: Takahashi
authors.forename: Miho
authors.initials: M
authors.lastname: Oikawa
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kumamoto
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tachi
mesh_terms: D020341:Absorbable Implants; D000497:Alloys / Q000737:chemistry; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D003343:Corrosion; D005593:Fracture Fixation, Internal; D008274:Magnesium / Q000737:chemistry; D008297:Male; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D051381:Rats; D017208:Rats, Wistar; D014025:Titanium / Q000737:chemistry; D055114:X-Ray Microtomography
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D014025:Titanium; D008274:Magnesium