BPD (bronchopulmonary dysplasia) is predominantly characterized by persistent abnormalities in lung structure and arrested lung development, but therapy can be palliative. While promising, the use of BMSC (bone marrow-derived mesenchymal stem cell) in the treatment of lung diseases remains controversial. We have assessed the therapeutic effects of BMSC in vitro and in vivo. In vitro co-culturing with injured lung tissue increased the migration-potential of BMSC; and SP-C (surfactant protein-C), a specific marker of AEC2 (type II alveolar epithelial cells), was expressed. Following intraperitoneal injection of BMSC into experimental BPD mice on post-natal day 7, it was found that BMSC can home to the injured lung, express SP-C, improve pulmonary architecture, attenuate pulmonary fibrosis and increase the survival rate of BPD mice. This work supports the notion that BMSC are of therapeutic benefit through the production of soluble factors at bioactive levels that regulate the pathogenesis of inflammation and fibrosis following hyperoxia.

MicroRNAs (miRNAs) are 21–25 nt long non-coding RNA that modulate various biological processes, including developmental timing via regulating the expression of their target genes. One critical determinant of normal postnatal lung architecture is septation, and there are many miRNAs involved in the development process. miR-134 is reported as a powerful inducer of pluripotent stem cell differentiation, and we have found that miR-134 is strongly downregulated during mice lung septation (from postnatal Day 2 to postnatal Day 21). Further cell function experiments have revealed that over-expression of miR-134 in A549 and Calu-3 cells can promote cell proliferation and inhibit cell apoptosis and migration abilities in vitro, and the down-expression of miR-134 in cells can act in the opposite way, which indicate that miR-134 is associated with lung septation. This study provides a basis for further investigation of its function in lung development.