Figure 2.

Effect of low oxygen tension preconditioning on PMSC osteogenic differentiation and multipotency. PMSCs were cultured in nondifferentiation or osteogenic differentiation conditions containing 15% FBS in room air (20% O₂) or low oxygen levels (1% O₂) for 14 days as in Figure 1. For low/room treatment, PMSCs were cultured for 7 days in low oxygen and followed by 7 days in room air (shown in the third panel). Alizarin red or alkaline phosphatase staining was used to detect calcium deposition and enzyme expression changes as shown morphologically in (a) and quantified in (b) (two-way ANOVA, P < 0.05, N = 4); lowercase letter (a, b, and c) indicates significance between oxygen tension effects within nondifferentiation condition, uppercase letter (A, B, C) indicates within differentiation conditions. From immunoblots shown in Figure S2, protein levels were quantified in (c) OCT4, (d) SOX2, and (e) RUNX2 levels. Quantification levels shown were normalized to β-actin, a protein loading control (two-way ANOVA, P < 0.05, N = 3). ∗ indicates significance between room air and low oxygen tension; lowercase letter (a, b, and c) indicates significance between oxygen tension effects within nondifferentiation condition, uppercase letter (A, B, and C) indicates within differentiation conditions.