Effects of pure oxygen inhalation at high altitude on brain function in rats
TU Lei
MA Heng
LIU Manling
LIU Xiaopeng
Abstract：Objective To explore the effect of inhaling pure oxygen at an altitude of 10 000 m on brain structure and function in rats.Methods Male SD rats were randomly divided into normal control group,normal pure oxygen inhalation 4,6,8 h/d group,air inhalation 4,6,8 h/d group at an altitude of 10 000 m,pure oxygen inhalation 4,6,8 h/d group at an altitude of 10 000 m.The rats in the normal control group inhaled air for 2 weeks under normal pressure.The rats in the normal pure oxygen inhalation group were placed in a hyperoxia chamber for 4-8 h/d for 2 weeks.The remaining rats were placed in a low-pressure hyperoxia chamber for 4-8 h/d for 2 weeks.The survival rate,Morris water maze test,brain water content,Evans blue(EB)content,and Na+/K+-ATPase activity in brain tissue were measured.At the same time,brain slices were prepared for HE staining and TUNEL staining to detect morphological changes in brain tissue.In addition,brain tissue homogenates were prepared to detect the contents of inflammatory factors such as TNF-α,IL-1 β and IL-6,and the changes of oxidative stress indexes such as catalase(CAT),malondialdehyde(MDA),manganese superoxide dismutase(MnSOD)and reactive oxygen species(ROS).Results All the rats in the air inhalation group at an altitude of 10 000 m died,while all the rats in the pure oxygen inhalation group at an altitude of 10 000 m survived.There were no significant differences in the escape latency and spatial search ability during navigation experiments between rats in the pure oxygen inhalation group at an altitude of 10 000 m for 2 weeks(4-8 h/d)and in the normal control group.Meanwhile,brain water content,EB content,and Na+/K+-ATPase activity in brain tissue were not significantly different with those in the normal control group.At the same time,pure oxygen inhalation for 2 weeks(4-8 h/d)at an altitude of 10 000 m did not affect the hippocampal tissue structure of rats,no significant infiltration of inflammatory cells was observed under the microscope,the inflammation score did not increase,and the number of TUNEL-positive cells in the hippocampal tissue of rats also did not increase.The contents of inflammatory factors such as TNF-α,IL-1β and IL-6 and the contents of oxidative stress molecules such as MnSOD,CAT,MDA,and ROS in brain tissue of rats also had no significant increase.Conclusion Pure oxygen inhalation at an altitude of 10 000 m(4-8 h/d for 2 consecutive weeks)is safe and effective,which neither cause a decrease in spatial learning and memory abilities of rats,nor induce the formation of brain edema,inflammatory damage or oxidative stress injury on brain tissue.Pure oxygen inhalation at an altitude of 10 000 m(4-8 h/d for 2 consecutive weeks)can effectively avoid high-altitude hypoxia and will not cause oxygen poisoning leading to serious brain tissue damage and brain dysfunction.This study provides parameters,basis and guidelines for the evaluation of high-altitude work protection under aerospace conditions.
Keywords：high-altitude flightinhaling pure oxygenbrain dysfunctionbrain tissue damage
Publication Date：2025-01-27
Online Publishing Date：2026-08-26(First online date of this platform, not the publication date of the document)