Vascular hyperreactivity in a rat model of bronchopulmonary dysplasia (715.2)

Abstract

Bronchopulmonary dysplasia (BPD) develops in ~30% of premature infants and is associated with decreased alveolar and vascular development. We hypothesized that BPD is also associated with vascular hyperreactivity to hypoxic and hyperoxic challenges. A rat model of BPD was created by exposing newborn Sprague Dawley rats to 95% O2 (BPD) for 8 days after birth. Controls (CTL) were exposed to 21% O2. At 21‐25 days old, rats were anesthetized and a Millar conductance catheter was inserted into the left ventricle to obtain cardiac output. A fluid‐filled catheter was inserted into the right ventricle (RV) to measure pressure. Rats were ventilated with 100% O2 (10 min), and 10% O2 (10 min) and pulmonary vascular resistance (PVR) was calculated for each condition by dividing the RV pressure by cardiac output. BPD rats had RV hypertension at baseline compared to CTL (31±5 mmHg vs 16±2 mmHg, p=0.028), largely caused by increased cardiac output. Contrary to our hypothesis, BPD rats demonstrated little change in PVR to hypoxia and hyperoxia, suggesting that vascular reactivity is impaired in BPD. Given the observed baseline RV hypertension in the BPD group, our future studies will aim to investigate the impact on myocardial contractility in this model.Grant Funding Source: Supported by NIH 5R01HL115061