FIG. 4.

The influence of co-culture and oxygen tensions on gene and protein expression levels. (A) Gene expression of controls and co-cultures, normalized to P0, HPRT, and PPIA expression levels are expressed as fold-increase relative to the MSC only expression in normoxic (N) conditions (n=3). Normoxic groups are shown in white, and hypoxic groups are shown in gray. The co-cultures were maintained in osteogenic medium for 7 days (*p<0.05; **p<0.01; ***p<0.001; asterisks located above a column indicate a significant difference compared with all other groups). (B) VEGF protein release into the culture medium after 3 and 7 days for MSCs or co-cultures (MSC/ECFC, n=1). VEGF, vascular endothelial growth factor.