VEGFA and bronchopulmonary dysplasia: In a BPD rat model, UC-MSCs reduced apoptosis, calpain I expression, active oxygen production, and abnormal elastin expression and deposition in vitro and promoted proliferation, anoxia-inducing factor-1a expression, VEGF secretion, and human umbilical vein endothelial cell lumen formation; in vivo, they can restore alveolar structure and pulmonary function, improve pulmonary hypertension, and increase vascular density [108,109].