Impact of Exposure Duration to High-Altitude Hypoxia on Oxidative Homeostasis in Rat Brain Regions
Boris Lira-Mejía, Roger Calderon-Romero, Jorge Ordaya-Fierro, Cristian Medina, José-Luis Rodríguez, Alejandro Romero, Roberto Dávila, Mariella Ramos-González
Abstract
Hypoxia at altitudes above 3000 m poses a significant threat to organ health and physiological homeostasis, particularly in metabolically active tissues such as the brain. Many of the cellular alterations induced by hypoxia are associated with the excessive generation of reactive oxygen species (ROS) and the resulting oxidative stress. In this study, we investigated the effects of exposure duration and altitude levels on oxidative homeostasis in the rat hypothalamus, cortex, hippocampus, and striatum. We assessed ROS production, malondialdehyde (MDA) levels, the antioxidant activities of superoxide dismutase (SOD), and catalase, as well as molecular biomarkers of oxidative stress, cell death, and inflammation. Our findings demonstrated that ROS, MDA and SOD levels increased across all brain regions, particularly in response to higher altitude exposure. Conversely, catalase activity decreased under the same conditions. At the molecular level, we observed overexpression of key biomarkers related to oxidative stress, cell death, and inflammation, especially at extreme altitudes. Furthermore, these effects were most pronounced in the hippocampus, cortex, and striatum. In conclusion, our data indicate that hypoxic exposure at higher altitudes significantly contributes to the oxidative disruption of brain homeostasis in rats.