RESUMO
Blocks of Bovine bone have shown promising results as implantable scaffolds to promote bone regeneration. Strontium ranelate (SrR) is both an antiresorptive and an anabolic drug that has been indicated for oral administration to treat osteoporosis. Few studies, however, have investigated the local effects of SrR and its use in association with biomaterials thus far. In this work, we investigated SrR effects in cultures of primary osteoblasts (PO, from Wistar rats calvaria) and immortalized osteoblasts (IO, from MC3T3-E1 cell line) cultivated as a monolayer or in association with scaffolds of bovine bone in mineralized (MBB) and demineralized (DBB) forms. The optimum dose to induce SrR effects on cell viability was established as 0.1 mM. Our results suggested that the local administration of SrR is biocompatible and non-cytotoxic. In addition, SrR appeared to accelerate primary osteoblast cell differentiation by enhancing alkaline phosphatase activity, the expression of osteogenic differentiation markers, the synthesis of the organic matrix, and a decrease of Ca2+ ions in mineralized nodules. DBB was found to be a better scaffold material to promote PO and IO cell proliferation. Exposing the proteins of the demineralized bone matrix might improve scaffold osteoconductive properties. Our results indicated the importance of further investigation of the administration of SrR at sites of bone repair. The association of SrR and bone grafts suggests the possibility of using SrR as a co-adjuvant for bone tissue bioengineering and in bone regeneration therapies.
Assuntos
Osso Esponjoso/efeitos dos fármacos , Osteoblastos/efeitos dos fármacos , Tiofenos/farmacologia , Alicerces Teciduais/química , Fosfatase Alcalina/metabolismo , Animais , Calcificação Fisiológica/efeitos dos fármacos , Cálcio/metabolismo , Bovinos , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Colágeno/biossíntese , Regulação da Expressão Gênica/efeitos dos fármacos , Íons , Camundongos , Osteoblastos/metabolismo , Osteogênese/efeitos dos fármacos , Ratos WistarRESUMO
ABSTRACT: Dental pulp stem cells (DPSC) have been showing a considerable potential for regenerative medicine. Pulps were collected from lower incisors (n=2) through direct access of the tooth pulp chamber. The isolated cells were cultured in alfa-MEM 10% FBS, in standard culture conditions. At the third passage, DPSC were characterized by flow cytometry (MHCI, CD54, CD73, CD90, CD45, CD11 and CD34); RT-PCR for Nanog gene; and their differentiation capacity in osteogenic, adipogenic and chondrogenic cell lines. Isolated cells exhibited adhesion capacity to plastic; fusiform morphology, and 80% confluence reached in approximately 3 days. These cells have also revealed positive expression for CD54, CD73 and CD90 markers; and negative expression for CD11, CD34 and CD45. Nanog expression was detected by RT-PCR, expected for a mesenchymal stem cell profile. DPSC chondrogenic differentiation was confirmed by positive staining in Alcian Blue; lipidic droplets stained with oil red confirmed their capacity to differentiate in adipogenic fate; while mineralized beads, stained with alizarin red, confirmed their differentiation in osteogenic phenotype. These results indicate the viability of the isolation and expansion of rat DPSC following this method, and osteogenic differentiation potential opens new perspectives for in vivo studies and the use of these cells in cellular therapies and tissue bioengineering, aiming bone repair.