Looking for the Mount Everest in Utero Memory.

CZERNICZYNIEC, A.; ROMERO FERNANDEZ, M.A.; KARADAYIAN, A.; LORES ARNAIZ, S.; COSTA, L.E.; LA PADULA, P.

Buenos Aires

Simposio; Frontiers in Bioscience Symposium 4th edition.; 2024

Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA), Partner Institute of the Max Planck Society

In the gestational stage, organisms are physiologically adapted to hypoxia (Mount Everest in utero, pO2 equivalent to 8849 m).The aim of this work was to evaluate the persistence of this potential beneficial effect in weaned animals exposed to acute hypoxia. Considering that the heart and the brain are the most sensitive organs to hypoxia the study involves a comparative mitochondrial functionality between cardiac left ventricle, cerebral cortex and hippocampus.Male Wistar rats of 21 days-old just weaned were subjected to a simulated 4,400 m altitude (58.7 kPa=440 mmHg) in a hypobaric chamber during 48h. A group of the same number of sibling rats remained as controls at sea level (101.3 kPa=760 mmHg). Oxygen consumption, mitochondrial membrane potential and hydrogen peroxide (H2O2) production were measured.Preliminary results showed a decrease in membrane potential (12%), and a tendency to increase in oxygen consumption (26%) and H2O2 production (30%) in mitochondrial cardiac left ventricles from exposed animals. Regarding the brain, acute hypobaric hypoxia decreased membrane potential (12%), tended to increase oxygen consumption (29%) and increased H2O2 levels (59%) in cerebral cortex. However, the same exposure preserved H2O2 production, induced membrane hyperpolarization (28%) and a decreased tendency in oxygen consumption (22%) in the hippocampus. Summing up, hippocampal brain mitochondria from 21 day-old animals would be less sensitive to the oxidative impact as compared to heart and brain cortex mitochondria, and could be related to spatial and memory functions needed for the recently weaned organism. We suggested that the observed protected mechanisms displayed at hippocampal level would be associated with the memory of gestational hypoxia. Meanwhile, cardiac left ventricle and cerebral cortical mitochondria from animals exposed to acute hypobaric hypoxia resisted the impact of increased reactive oxygen species through an increment in blood supply.