An intra-amniotic injection of mesenchymal stem cells promotes lung maturity in a rat congenital diaphragmatic hernia model.

Purpose: We aimed to evaluate the effect of human mesenchymal stem cells (hMSCs) on congenital diaphragmatic hernia (CDH) by intra-amniotic injection in a rat CDH model.
Methods: Nitrofen (100 mg) was administered to pregnant rats at E9.5. hMSCs (1.0 × 10 ⁶ ) or PBS was injected into each amniotic cavity at E18, and fetuses were harvested at E21. The fetal lungs were classified into normal, CDH, and CDH-hMSCs groups. To determine the lung maturity, we assessed the alveolar histological structure by H&E and Weigert staining and the alveolar arteries by Elastica Van Gieson (EVG) staining. TTF-1, a marker of type II alveolar epithelial cells, was also evaluated by immunohistochemical staining and real-time reverse transcription polymerase chain reaction.
Results: The survival rate after intra-amniotic injection was 72.1%. The CDH-hMSCs group had significantly more alveoli and secondary septa than the CDH group (p < 0.05). The CDH-hMSCs group had larger air spaces and thinner alveolar walls than the CDH group (p < 0.05). The medial and adventitial thickness of the pulmonary artery in the CDH-hMSCs group were significantly better (p < 0.001), and there were significantly fewer TTF-1-positive cells than in the CDH group (p < 0.001).
Conclusion: These results suggest that intra-amniotic injection of hMSCs has therapeutic potential for CDH.