CXCL12 and bronchopulmonary dysplasia: qRT-PCR and western blot analyses indicated that the mRNA and protein levels of CXCR4, SDF-1, and VEGF were significantly decreased in the lung tissue of three treatment groups when compared with the BPD group; moreover, a greater improvement was observed in the MSCs+EPO group compared with the MSCs or EPO group alone (P < 0.05, Figure 5A–5C).