Hepatocyte Growth Factor Treatment Improves Alveolarization in a Newborn Murine Model of Bronchopulmonary Dysplasia

BACKGROUND: Bronchopulmonary dysplasia (BPD) is thought to be one form of developmental arrest of the lung. Hepatocyte growth factor (HGF) participates in normal lung growth and in lung regeneration. OBJECTIVES: The purpose of this study is to investigate whether HGF can improve alveolarization and attenuates functional abnormalities of a murine model of BPD induced by hyperoxia. METHODS: Three-day-old CD-1 mice were exposed to 90% of oxygen or room air (control group) for 7 days. These animals were then kept in room air for the next 7 days. Recombinant human (rh) HGF (100 microg/g b.w., divided 3 times, rhHGF group) or vehicle (vehicle group) was administered intraperitoneally during hyperoxia. On day 17, the pulmonary function test and bronchial hyperresponsiveness (BHR) were examined. Mean linear intercepts (MLI) were measured as parameters of alveolarization. Cell renewal (on day 10) and vascularization of the lung were also evaluated. RESULTS: Exposure to hyperoxia induced increased airway resistance and BHR. These animals showed a severely simplified alveolar structure, increased MLI, decreased cell renewal (16.1 +/- 2.4 vs. 29.6 +/- 2.4%, p < 0.05), and decreased vascularization (15.1 +/- 0.3 vs. 18.4 +/- 1.5 vessels/hpf, p < 0.05, vehicle vs. control group, respectively). rhHGF treatment during exposure to hyperoxia significantly reduced all of these changes (27.9 +/- 1.7%, 18.2 +/- 0.5 vessels/hpf for cell renewal and vascularization, respectively; all values are p < 0.05 against vehicle animals). CONCLUSION: HGF partially protects against the inhibition of alveolarization and improves functional abnormality in the hyperoxia-induced neonatal mice model of BPD.