課題番号 ：S-15-NM-0056
利用形態 ：機器利用
利用課題名（日本語） ：細胞培養環境下での生体用マグネシウム合金の腐食評価
Program Title (English) ：The influence of macrophages on in vitro corrosion of magnesium alloy
利用者名（日本語） ： 張　健1), 廣本祥子1)
Username (English) ：J. Zhang1), S. Hiromoto1)
所属名（日本語） ：上海交通大学
Affiliation (English) ：Shanghai Jiao Tong University

１．概要（Summary ）
After the implantation of medical devices, macrophages will aggregate at the implantation site. Macrophages secrete reactive oxygen species (ROS) which should influence the corrosion of the implanted material. In this study, macrophages were cultured on Mg alloy and the corrosion behavior of Mg alloy and the ROS secretion were examined. The attachment of macrophages to the magnesium surface accelerated the ROS secretion and the corrosion of Mg alloy was doubled.
２．実験（Experimental）
After the proliferation of RAW264.7 macrophages were stopped using mitomycin C, the cells were seeded on Mg-Nd-Zn-Zr (JDBM) alloy and cultured for 72 h or 168 h. The mass loss of samples, medium Mg ion concentration and pH were measured. Mg alloy samples without cell co-culture were used as control. ROS concentration was measured.
３．結果と考察（Results and Discussion）
Corrosion rate of the Mg alloy was doubled in the presence of macrophages as shown in Fig. 1. The corrosion appeared to continue at the constant speed regardless of the incubation period.
Figure 2 shows the obvious secretion of ROS from macrophages cultured on Mg alloy. The cells on glass plate rarely secreted ROS.
Consequently, the ROS secretion of macrophages is accelerated with Mg alloy, and vice versa the corrosion of Mg alloy is accelerated with macrophages.

Fig. 1 Corrosion rate of Mg alloy with and without macrophages. The rate was evaluated from mass loss of the ally samples.

Fig. 2 Fluorescence images of macrophages cultured on Mg alloy and glass plate for 72 h. (a,d) cell nuclei, (b,e) ROS level, (c,f) overlay. (a-c) on Mg alloy, (d-f) on glass plate. Scale bar = 100 μm.

４．その他・特記事項（Others）
共同研究者：山崎智彦（物質・材料研究機構）
５．論文・学会発表（Publication/Presentation）
(1) J. Zhang, S. Hiromoto, T. Yamazaki, J. Niu, H. Huang, G. Jia, H. Li, W. Ding, G. Yuan, J. Biomed. Mater. Res. A (submitted).
６．関連特許（Patent）
なし。