Investigating the interplay of immune response and redox homeostasis in hypoxic brain injury at high altitude

Environments at high altitudes, where barometric pressure is low and oxygen levels are diminished, significantly heighten the risk of High-Altitude Cerebral Edema (HACE), a potentially life-threatening neurological disorder. HACE induces a robust inflammatory response, disrupting redox balance in the brain and causing neurocyte swelling and degeneration. This study evaluated changes in apoptotic cells, mast cells (MCs), and the expression of TNF-α, a key mediator of neuroinflammation, following acute hypobaric hypoxia. Furthermore, changes in the activities of superoxide dismutase (SOD), catalase (CAT), and lactate dehydrogenase (LDH) were examined to evaluate disruptions in the redox balance and potential disturbances in cell energy metabolism within the brain. The animals were exposed to hypobaric hypoxia for roughly 24 hours at an altitude of 7620m. The findings revealed a significant increase in MCs in the brain tissue (p<0.001), along with an elevated number of TNF-α and apoptotic cells, suggesting considerable neuronal degeneration (p<0.05). The activities of SOD and CAT were decreased (p<0.01), which shows weakened antioxidant defense mechanisms following the hypoxic exposure. However, the changes of LDH level remained unaltered. These results underscore the critical role of the immune reaction of the brain triggered by the hypoxic conditions that aggravate cerebral edema development. This study illustrates the interplay of inflammatory response with an antioxidant defense system in the context of blood-brain barrier (BBB) disruption, contributing to cerebral edema formation and neuronal dysfunction. This research deepens our understanding of the pathogenesis of HACE, highlighting the interactions between specific biomolecules that regulate the brain’s immune reaction and redox pathways under hypoxic conditions.