Morphological changes in the ductus arteriosus in response to development in hypoxia and hyperoxia

Abstract

The ductus arteriosus (DA) is an oxygen sensitive fetal blood vessel that allows for a right‐to‐left shunt of right ventricular outflow away from the lungs. Previously we have shown that the maturation of the oxygen induced contraction of the DA can be altered by incubation under varying O2 levels. The objective of this study was to characterize the influence of development in hypoxia or hyperoxia on the morphological changes occurring in the chicken DA during hatching. White leghorn chicken eggs were incubated in normoxia (21% O2), hypoxia (15% O2), and hyperoxia (30% O2) for the entire incubation period. The DA was removed from day 18, internally pipped, and externally pipped embryos and hatchlings for histological examination. The major finding was a significant effect of incubation oxygen levels on the DA lumen diameter during hatching. During hatching, the DA lumen diameter from hyperoxic incubated embryos was significantly smaller than that from control embryos. Incubation in hypoxia resulted in a decrease in the closure of the DA in comparison to the control embryos. A similar pattern was observed in the overall length of the right and left DA. The timing of morphological closure of the O2‐sensitive DA is accelerated by in hyperoxia and delayed in hypoxia. This work was funded by the American Heart Association South Central Affiliate and the National Science Foundation.