Murine Double Hit Model for Neonatal Cardiopulmonary Diseases: Bronchopulmonary Dysplasia (BPD) and Pulmonary Hypertension Associated with BPD

Steven P Garrick; Philip J Berger; Marcel F Nold; Claudia A Nold-Petry

doi:10.21769/BioProtoc.4669

Murine Double Hit Model for Neonatal Cardiopulmonary Diseases: Bronchopulmonary Dysplasia (BPD) and Pulmonary Hypertension Associated with BPD

Bio Protoc. 2022 Nov 5;12(21):e4669. doi: 10.21769/BioProtoc.4669.

Authors

Steven P Garrick^{1

2}, Philip J Berger^{1

2}, Marcel F Nold^{1

2

3}, Claudia A Nold-Petry^{1

2}

Affiliations

¹ Department of Paediatrics, Monash University, Melbourne, Victoria 3168, Australia.
² Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria 3128, Australia.
³ Monash Newborn, Monash Children's Hospital, Melbourne, Victoria 3168, Australia.

Abstract

Bronchopulmonary dysplasia (BPD) and pulmonary hypertension associated with BPD (BPD-PH) are of multifactorial origin and share common risk factors. Most murine models of BPD expose newborn pups to only one of these risk factors-more commonly postnatal hyperoxia-thereby mimicking the vital increased fraction of inspired oxygen (FiO2) that preterm infants in neonatal intensive care units often require. To improve representation of the multifactorial origins of BPD and BPD-PH, we established a double hit model, combining antenatal systemic inflammation followed by postnatal hyperoxia. On embryonic day 14, pups are exposed to systemic maternal inflammation via a single intraperitoneal injection of 150 µg/kg of lipopolysaccharide to the dam. Within 24 h after birth, pups and dams are randomized and exposed to gas with either an FiO2 of 0.21 (room air) or 0.65 (hyperoxia 65%). In our BPD and BPD-PH double hit model, we can obtain multiple readouts from individual pups that include echocardiography, lung histology and immunohistochemistry, ex vivo X-ray micro computed tomography, and pulmonary and plasmatic immunity by RNA, protein, or flow cytometry. This protocol was validated in: Sci Transl Med (2022), DOI: 10.1126/scitranslmed.aaz8454 Graphical abstract Figure 1. Murine double hit model of cardiopulmonary disease. On embryonic day (E)14, pups are exposed to systemic maternal inflammation via a single intraperitoneal injection of 150 µg/kg lipopolysaccharide to the dam. Within 24 h after birth, pups and dams are randomized to be exposed to gas with either a fraction of inspired oxygen (FiO ₂ ) of 0.21 (air; 21% O ₂ ) or 0.65 (hyperoxia; 65% O ₂ ) for a maximum of 28 days. According to the murine stage of lung development ( Schittny, 2017 ), experimental endpoints include postnatal day (D)3, D5, D14, D28, and D60.

Keywords: Antibody Therapy; Bronchopulmonary Dysplasia; Clinical Translation; Early Life Cardiopulmonary Disease; Immunology; Inflammation; Neonatology; Preclinical Murine Model; Pulmonary Hypertension.