Associação de células tronco da polpa dentária a enxertos ósseos desmineralizados para otimização de reparos ósseos

Abstract

The use of xenografts derived from bovine bone has been configured as an alternative to autografts in the replacement of bone loss. However, its property of osteoinduction and osteogenic potential are still limited. For this reason, some strategies such as demineralization of bone fragments as well as the use of mesenchymal stem cells have been proposed for the optimization of bone repair. In this context, this study evaluated the effects of the association of a bone matrix of bovine origin, commercial brand - Criteria ®, demineralized in EDTA 10%, to the CTPDs (modified for eGFP - enhancedgreenfluorescentprotein) in the repair of an intrabuccal bone defect in rats. The defects were filled by: 1. Demineralized bone matrix (MOD); 2. TDPs in suspension; 3. CTPD + MOD; 4. Blood clot (control). The animals were sacrificed after 7, 14 and 49 days for histomorphometric and immunohistochemical evaluations for GFP (aiming at the monitoring of transplanted stem cells); and after 3 and 7 days for expression analysis of genes indicative of osteoblastic differentiation (Runx2, Osx and iBSP) by RT-PCRq. At 7 days, epithelial closure was incomplete in all groups. Morphometry demonstrated that bone deposition in the area of the surgical defect was higher in the group that received the proposed association, followed by grafting with the isolated TCDC's. This result is in agreement with the molecular analysis, which demonstrated the expression of the osteoblast differentiation marker iBSP, 64 times higher in the same period. This pattern of bone deposition in the morphometric analysis was maintained in the periods of 14 and 49 days, evidencing the beneficial association between CTPD + MOD for tissue regeneration therapies. The maturation level of the matrix was evaluated by staining of PicroSirius Red and revealed the highest maturation in the CTPD + MOD group. Briefly, the results demonstrated optimization of the bone regeneration process with the association CTPD + MOD in all periods. The study brings clarifications about the xenograft of national manufacture and presents an optimization proposal for its use in the development of tissue regeneration therapies.