Three-dimensional visualization of bioactive glass-bone integration in a rabbit tibia model using synchrotron X-ray microcomputed tomography

Abstract

Synchrotron X-ray microcomputed tomography (SR microCT), with a micron resolution, was used to evaluate the osteoconduction and osteointegration by borate bioactive glass after implantation 12 weeks in a rabbit tibia model. The study focused on the biomaterial-bone interface. Results from SR microCT two-dimensional and three-dimensional (3D) reconstructions provided precise imaging of the biomaterial-bone integration and detailed microarchitecture of both the bone-like glass graft and the newly formed trabecular bone. Osteoconduction, the formation of new trabecular bone within a tibia defect, occurred only in the tibiae implanted with teicoplanin-loaded borate glass but not in those with teicoplanin-loaded CaSO(4) beads, indicating the excellent biocompatibility of the glass implants. 3D reconstruction of the tibiae also showed the infiltration of vascular tissue in both the bioactive glass graft and the new trabecular bone. This study indicates that SR microCT can serve as a valuable complementary technique for imaging bone repair when using bioactive glass implants.

FIG. 1.

Optical image of the tibia postharvesting: (a) empty control; (b) implanted with teicoplanin-loaded CaSO₄ beads; (c) implanted with teicoplanin-loaded borate glass. Color images available online at www.liebertonline.com/tea

FIG. 2.

Two-dimensional reconstructed section of a tibia defect (a) and (b) without implantation (empty control); (c, d) implanted with teicoplanin-loaded CaSO₄ beads. Bright area, host bone; gray area, vascular tissue; black area, background.

FIG. 3.

(a, b) Two-dimensional reconstructed section of a tibia defect implanted with teicoplanin-loaded borate glass; (c, d) hematoxylin and eosin staining of the same implant; (e, f) Goldner's trichrome staining. The bright area indicates the cortical bone; light gray, the newly formed trabecular bone and the bone-like graft converted from borate glass; dark gray area, the vascular tissue. G, glass-converted graft; B, bone; NB, new bone; HB, host bone; V, vascular tissue. Color images available online at www.liebertonline.com/tea

FIG. 4.

Three-dimensional reconstructed blocks of a tibia defect (a, b) without any implant (empty control); and (c, d) implanted with teicoplanin-loaded CaSO₄ beads. No detectable new bone formation was observed to fill the bone defects in both groups of implants. Yellow area, host bone; red area, vascular tissue. Color images available online at www.liebertonline.com/tea

FIG. 5.

(a) Three-dimensional reconstructed blocks of a tibia defect implanted with teicoplanin-loaded borate glass; (b) infiltration of vascular tissues (in red) in the glass graft (in blue); (c) integration between the glass graft and new bone (in gray); (d) new trabecular bone formed in peripheral area from the old trabecular and cortical bone (in yellow). Color images available online at www.liebertonline.com/tea

FIG. 6.

(a) Gross view of a three-dimensional reconstructed tibia defect implanted with teicoplanin-loaded borate glass; (b) cross-sectional view of the same tibia; (c) high-resolution image of the trabecular bone; (d) high-resolution image of the converted glass graft. Yellow area, bone; blue area, glass graft. Color images available online at www.liebertonline.com/tea