OBJECTIVE
To evaluate the osteogenic properties of porous polylactide granules (PLA) and hydroxyapatite granules (HA) impregnated with recombinant bone morphogenetic protein-2 (BMP-2) in vitro and in vivo.
MATERIALS AND METHODS
Osteogenic differentiation in the presence of polylactide granules was studied in a culture of mesenchymal stromal cells obtained from rat adipose tissue (MSC-AT). For this purpose, the expression of the Bmp2, Spp1, and Bglap genes and the production of osteocalcin and osteopontin proteins were analyzed, as well as the mineralization of the intracellular matrix. In vivo, the osteogenic properties of PLA granules and two types of hydroxyapatite with BMP-2 were studied using a model of orthotopic osteogenesis. After 28 days, histological analysis and morphometry were performed to assess the volume of newly formed bone tissue and connective tissue surrounding and sprouting into the material.
RESULTS
Polylactide granules with BMP-2 stimulated the osteogenic differentiation of MSC-AT, caused an increase in the expression of genes for markers of osteogenic differentiation, Bmp2, Spp1 and Bglap, and the production of proteins osteopontin and osteocalcin, and contributed to the mineralization of the extracellular matrix. In vivo, the material based on polylactide granules with BMP-2 led to the formation of a larger volume of bone tissue, compared with hydroxyapatite HA-1 granules, and contributed to less fouling of connective tissue.
CONCLUSION
Highly porous polylactide granules impregnated with BMP-2 demonstrated osteogenic properties in in vitro studies, and were also characterized by better osteoinductive properties compared with impregnated BMP-2 hydroxyapatite granules in vivo. Thus, polylactide granules with recombinant BMP-2 can be used to produce highly effective bone graft materials for the restoration of bone defects in dentistry and maxillofacial surgery.
