[Ceramic 55S as a substrate for the regeneration of bone defects; an in vitro study]

The purpose of this work is to evaluate the in vitro behaviour and the capacity to induce osteoblastic differentiation of a 55S vitro-ceramic (Vc) on a population of adult rabbit mesenchymal stem-cells (MSCs).

The material was obtained using the sol-gel method. The cells were obtained from rabbit bone-marrow aspirate and seeded over the Vc, and over plastic (control). The MSCs were cultivated in two culture media; one a standard DMEM (growth medium), and the other an osteoblastic phenotype inducer, composed of DMEM complemented with dexamethasone, ß-glycerophosphate and ascorbic acid-2-phosphate (osteogenic medium). The morphology of the cells that grew was assessed using a scanning electronic microscope. The tetrazolium salt reduction test was used for evaluating the cell growth. For cell differentiation, osteocalcin production and loss of CD90 bone surface antigen, characteristic of MSCs, were quantified.

During the culture time the MSCs adhered, proliferated and formed a mineralised extracellular matrix over the Vc. An osteoblastic phenotype finally being shown, producing osteocalcin and decreasing the expression of the CD90 antigen, regardless of the culture medium used.

Based on these results we can state that Vc 55S behaved like a material capable of supporting adhesion and growth of MSCs and, in turn, inducing the differentiation of the MSCs to osteoblastic cell lines, thus showing osteoconduction and osteoinduction properties.