Unraveling Optimal Dose and Responsive Markers for Human Cord Blood Derived Mononuclear Cells in Alleviating Bronchopulmonary Dysplasia in Neonatal Mice.

Bronchopulmonary dysplasia (BPD), characterized by impaired alveolarization and dysregulated vascularization, is a severe health burden for neonates worldwide. Hyperoxia induced acute lung injury is a major contributor to the progression and deterioration of BPD. An increasing number of animal studies have revealed that human umbilical cord blood derived mononuclear cells (hUCB-MNCs) infusion significantly attenuated the hyperoxia-induced acute lung injury through regeneration capacity. Currently, clinical application requires determination of the optimal dose and adjustment to good manufacturing practices. In this work, we comprehensively investigated the optimal dose of hUCB-MNCs in alleviating hyperoxia-induced lung injury in neonatal C57BL6/J mice. Mice with hyperoxia exposure were implanted with low (3×10⁴ cells/kg, Dl), middle (3×10⁵ cells/kg, Dm) and high (3×10⁶ cells/kg, Dh) dose of hUCB-MNCs at postnatal day 7. Three weeks after graft, characteristics exhibited in lungs including morphology, function and cytokine expression were thoroughly analyzed. Implantation of hUCB-MNCs sharply reverted the impaired lung architecture induced by hyperoxia exposure dose dependently as evidenced by indicated parameters. Attenuated expression of IL-1β concomitant with enhanced expression of IL-10 and IL-2 were shown in Dh inoculated groups, where Dl and Dm failed to restore the level of IL-10, IL-1β and IL-2. Significantly re-escalated marker of angiogenic marker VEGFA, CD31 in lung tissue were uniquely observed in Dh group. Mechanistically, our study revealed the appropriate dose of intravenous infusion of hUCB-MNCs in alleviating hyperoxia-induced lung injury through modulating reactive oxygen species response in neonatal mice. Therefore, a tight control of hUCB-MNCs density or levels of CB-MNC related products is of great significance.