Influence of immunosuppression on osteoinductive properties of demineralized bone matrix - Experimental studies in rats

Background/Aim: The aim of the study was to evaluate the influence of immun osuppression and reduction of cytokin synthesis on osteoinductive capacity of demineralized bone matrix (DBM). Methods: DBM was implanted in Lewis rats and the following groups were inve stigated: autogeneic and xenogeneic DBM without immunosuppression (controls ) and autogeneic and xenogeneic DBM with immonosuppression by means of FK50 6 (1 mg/kg BW i,p per day). In-vitro cytokin synthesis (TNF-alpha), activit y of alkaline phosphatase in the ossicle and histomorphometric analysis of the induced bone and tibial metaphysis was performed. Results: Treatment with the immunosuppressant FK506 significantly enhanced bone induction in xenogeneic and non-immunogeneic isogeneic demineralized b one matrix. In contrary marked bone resorption caused bone loss in the tibi al metaphysis. Further on a reduced TNF-synthesis of whole blood was detect ed. Summary: We therefore propose positive and negative effects of FK506 on bon e metabolism being independent from immunosuppression.