Localization of bone matrix gene mrna in regenerating bone tissue during the guided bone regeneration

ABSTRACT

bone matrix proteins such as osteonectin(OSN), osteopontin(OPN) and osteocalcin(OSC) mRNA during bony healing procedure induced by guided bone regeneration method, we made artificial defects on bilateral femur of rats. Then induced bony healing by application of a nonabsorbable PTFE membrane in experimental sites and without its application in control sites for 3 weeks. The mRNA expression pattern at specimens obtained at 1, 2 and 3 weeks after operation was detected by in situ hybridization method using its antisense mRNA probes. The experimental sites revealed more rapid and favorable bony healing than control sites and new bone formation was limited within defected area by inhibitory activity of bone marrow cells. In experimental sites, the OSN and OSC mRNA were expressed strongly on osteoblasts of regenerating cortical bone at 1st week and on osteoblasts lining the trabecular bone in marrow space at 3rd week, whereas ,in control sites, their expression were noted on osteoblasts lining the reactively formed sponge bones at 2nd and 3rd week. In addition, the OPN mRNA was expressed on osteoblasts and osteoclasts at sites of remodeling and osteocytes of remained trabecular bone of defected area in experimental sites and on macrophages at 1st week and osteoclasts at sites of remolding at 2nd and 3rd week in control sites. The above findings suggest that the more rapid and favorable bony healing might be induced by blocking of invading fibrous connective tissue into bony defects. And the earlier expression of OSN and OSC mRNA on osteoblasts of experimental sites suggest that the formation and resorption of regenerating bone was more rapidly progressed in confined spaces made by applicate membranes.