Fig. 1.

The rat subcutaneous model allows the compartmentalization of the interface with the implants.

(A), The cellular response was characterized at three topographically distinct compartments of the soft tissue-implant interface: the cells adherent to the implant surface, the inflammatory fluid around the implant (exudate), and the soft tissue per se. (B), Four implants were inserted in each rat in addition to three sham wounds without implants. At 1-, 3-, 6-, 14-, and 28-days following implantation, the separate retrieval of implants, exudates, and tissues allowed the monitoring of Mg²⁺ concentration at the interface along with cellular (cell counts, cell viability, and cytotoxicity) and molecular analyses (gene expression with qPCR analysis; protein analyses with enzyme-linked immunosorbent assay [ELISA] and immunohistochemistry [IHC]). In addition, implants and tissues that were collected en bloc were allocated for morphometric analyses of tissues (histology and histomorphometry) and the Mg-degradation layer (SEM, secondary electron microscopy; EDX: energy dispersive X-ray spectroscopy). Random allocation of pockets to the different retrieval groups was achieved through a clockwise rotation scheme, as shown by the red circular arrow.