Abstract
The chronic sequelae of neonatal hyperoxia was studied in male rats exposed to 100% O2 for the first 8 days of life. Dams were rotated between 41 oxygen treated (O2) rats and 29 room air controls. Following O2, rats had standard care until 60 days of age. Survival rate was 97%. Body weights at 60 days were similar. In vivo right ventricular pressure was measured percutaneously under anesthesia and was increased in the O2 group (30.5 ± 4.3 vs 22.7 ± 3.3 mm Hg p <.0005). Hearts and lungs were excised at 63 days. Organ weights were similar between groups, however, right to left ventricular weight ratios were increased in the O2 group (.316 ± .028 vs .259 ± .022 p <.0005). Air pressure-volume curves were similar but in the O2 rats fluid deflation curves were shifted left and maximum fluid lung volumes were greater (14.05 ± 1.25 vs 12.03 ± .71 ml p <.0006). Pulmonary arteries were perfused at 100 cm H2O with a barium-gel mixture and lungs fixed at 25 cm H2O with formalin. Morphometric studies showed that the O2 rats had an increased volume proportion of parenchyma (.865 ± .014 vs .820 ± 2.8 p <.05), increased mean linear intercept (111.5 μ ± + 17.6 vs 75.3 μ ± 4.7 p <.005), decreased alveoli and ducts per mm2 (78.4 ± 5.2 vs 127.9 ± 8.4 p <.0005) and fewer small arteries (20-200 μ) per mm2 (2.9 ± .41 vs. 4.3 ± .57 p <.0005). The number of small arteries/100 alveoli were similar. We conclude that neonatal hyperoxia is associated with VPD as indicated by a decrease in the number of arteries, cor pulmonale and emphysematous changes in the air spaces.
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Shaffer, S., Thibeault, D., O'Neill, D. et al. 1831 VASCULAR-PULMONARY DYSPLASIA (VPD) ASSOCIATED WITH NEONATAL RAT HYPEROXIA. Pediatr Res 19, 416 (1985). https://doi.org/10.1203/00006450-198504000-01849
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DOI: https://doi.org/10.1203/00006450-198504000-01849