Non-vascularized bone isograft using GFP transgenic mice

Cheng Lin, DDS, PhD,(a) Bao-lin Liu, DDS,(a) Yan-pu Liu, DDS, PhD,(a) Xiao-hui Liu, DDS, PhD,(b) Xiao-guang Hu, DDS, MD,(a) Yan-liang Wang, DDS, PhD,(a) and De-lin Lei, DDS, MD(a)

(a)Department of Oral and Maxillofacial Surgery, School of Stomatology, The Fourth Military Medical University, Xi’an, and (b)Department of Stomatology, General Hospital of Lanzhou Military District, Lan-Zhou, P. R. China.

Purpose: To further understand the viability of the non-vascularized bone graft and the origin of the bone-forming cells, we have developed a novel mouse femur model that permits direct-viewing analysis of bone graft healing.
Materials and Methods: Critical size defects were prepared in one side of femur of 15 C57BL/6 mice and repaired by non-vascularized femur with intact periosteum and parts of muscles from isogenous GFP transgenic C57BL/6 mice. Sacrifice was performed 3 days, 1, 2, 3, and 4 weeks after surgery for histological and fluorescence microscopy analysis.
Results: Healing process of the transplants is similar to that of bone fracture. The osteoblasts and newly formed trabeculae which were beneath the grafted periosteum showed green fluorescent protein (GFP) expression, which was strongly expressed in the transplanted muscles.Conclusion: These data demonstrate that part of non-vascularized grafted bone can keep viability and has the potential of osteogenesis, indicating an important role for the grafted periosteum and bone in new bone formation.
(Int Chin J Dent 2007; 7: 87-91.)

Key Words: GFP transgenic mice, isograft, non-vascularized bone graft.