Abstract
Abstract
Background
Understanding fetal brain responses to hypoxiaischemia is of growing interest, as it remains unclear to what extent these responses differ from those of newborns and whether developmental adaptations during gestation contribute to such differences.
Materials and methods
Using a combination of broadband near-infrared spectroscopy (bNIRS) and diffuse correlation spectroscopy (DCS), we measured brain microvascular oxygen saturation (StO
2
), total hemoglobin concentration (THC), relative cerebral blood flow (rCBF), and the oxidation state of cytochrome c oxidase (oxCCO) during an acute ischemic challenge in the brains of five rabbit fetuses in utero. Simultaneous measurements were acquired from four control fetuses located in the contralateral uterine horn.
Results
During the hypoxia-ischemia phase, we observed a rapid reduction of CBF (47% ± 29%) and StO
2
, (from 64.7% ± 1.5% at baseline to 40.6% ± 2.0%) together with an increase of oxCCO (3.7μM ± 0.5μM).
Conclusion
The simultaneous increase in oxCCO and decrease in rCBF and StO
2
during hypoxia-ischemia reveals a cerebral response pattern that differs from that commonly reported in the newborn brain. These findings support the hypothesis that unique developmental adaptations influence fetal cerebral metabolism during hypoxic-ischemic stress.