PURPOSE: This study had two aims. First, to investigate the influence of recombinant human bone morphogenetic protein 2 (rhBMP-2) on growth, differentiation and mineralization of human ostosarcoma cells (SaOS-2) cultured on PLGA (poly lactic-co-glycolic acid) polymer .
Second, to identify transcriptional changes in the expression of Ets2 in three dimensional bone constructs treated with exogenous rhBMP-2.
MATERIALS AND METHODS: SaOS-2 cells were cultured over a period of 21 days on PLGA fleeces in the presence of different doses of rhBMP-2 (1 g/ml, 2 g/ml, 5 g/ml). These constructs were cultivated under osteogenetic differentiation conditions. Non rhBMP-2-treated cultures were served as controls. The expression patterns of type I collagen (Coll I), core binding factor (Cbfa I) and the transcription factor Ets2,were assessed after six, 14 and 21 days by semi quantitative RT-PCR. The DNA content was measured to assess cell growth while the activity of alkaline phosphatase (ALP) was measured to verify the osteoblastic character of the constructs.
RESULTS: Good cell growth of SaOS-2 cells on PLGA polymer could be seen.
The expression of the selected marker genes during the whole cultivation period verified the osteoblastic character of the constructs. Treatment of cell-seeded constructs with exogenous rhBMP-2 showed a dose dependent increase in Ets2 expression. CONCLUSION: The application of rhBMP-2 has strong effects on the expression of Ets2 transcription factor in cell-seeded three dimensional bone constructs in vitro.