168 DIFFERENTIATION OF MC3T3-E1 PREOSTEOBLASTIC CELLS ON TWO-DIMENSIONAL POLY(LACTIDE-CO-GLYCOLIDE) (PLGA) FILMS AND THREE-DIMENSIONAL PLGA SCAFFOLDS: A REAL-TIME REVERSE TRANSCRIPTASE-POLYMERASE CHAIN REACTION STUDY.

Purpose This study aimed to investigate the expression of a number of osteogenic and angiogenic markers in MC3T3-E1 cells cultured on two-dimensional (2-D) (PLGA films and three-dimensional (3-D) PLGA scaffolds. Methods MC3T3-E1 cells were incubated in mineralized medium in the absence or presence of 100 ng/mL recombinant human BMP-2 for 2 weeks. Cells were cultured either on 2-D PLGA films or in 3-D PLGA scaffolds and harvested on days 0, 1, 2, 3, 5, 7, 10, and 14. Total RNA was extracted and subjected to quantitative real-time reverse transcriptase-polymerase chain reaction analysis for expression of genes involved in osteogenesis and angiogenesis. Results Expression of BSP and OCN increased when cells cultured on 2-D PLGA films were subjected to differentiation medium containing ascorbic acid and beta-glycerol phosphate for a period of 2 weeks. Treatment with recombinant human BMP-2 resulted in further increases in expression of both genes after day 5. Cells cultured on 3-D PLGA scaffolds showed significantly slowed differentiation as measured by expression of the above two genes. Both genes remained highly responsive to BMP-2 treatment after day 5. OPN expression was elevated when cells were transplanted into 3-D scaffolds. Its expression in cells cultured in 3-D scaffolds was less responsive to BMP-2 treatment than on 2-D films. Expression of VEGF was increased as differentiation proceeded on 2-D films and was enhanced with BMP-2 treatment. Its expression was significantly induced when cells were cultured in 3-D scaffolds. A 2-week culture of cells in 3-D scaffolds resulted in decreased VEGF expression. BMP-2 inhibited VEGF expression in 3-D scaffolds at days 10 and 14. Conclusions The results indicate that MC3T3-E1 cells commit to osteogenic differentiation at a slower rate in 3-D scaffolds than in 2-D scaffolds.