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Studies on the Effects of Fulminating Altitude Hypoxia and Enriched Oxygen Protection on Rats

Author: QinZhiFeng
Tutor: XiaoHuaJun
School: Fourth Military Medical University
Course: Aviation, aerospace and maritime medicine
Keywords: fulminating altitude hypoxia molecular sieve oxygen generation system(MSOGS) enriched oxygen behavior changes ulrrastructure C-FOS EPO gene expression
CLC: R855
Type: Master's thesis
Year: 2002
Downloads: 75
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Abstract

Acute altitude hypoxia and fulminating altitude hypoxia is the most harmful one of many worse environmental factors for pilots. In modern aviation technology, although there is fine oxygen system, pilots often suffer from different hypoxia because of loss of cabin pressure, unfitness of mask, trouble with oxygen system, and so on. Scholars of many countries have studied altitude hypoxia for a handred years. With the development of molecular biological technology, the pathological and physiological studies of hypoxia are pushed forward. It is found in many studies that there is a series of changes of hypoxia-related-gene during clinical hypoxia, such as erythropoietin(EPO) gene, immediately early gene(IEGs) gene. The expression of these genes are all increased. But there is few studies on acute altitude hypoxia and fulminating altitude hypoxia in gene. Acute altitude hypoxia and fulminating altitude hypoxia are special hypoxia, this kind of hypoxia can also change EPO gene and lEGs gene’s expression. It has aroused aviation medicine scholars’ interesting.It is not clear that how different enriched oxygen gas protects aircrew and passenger during emergency oxygen supply, especially, under the condition of passenger’s mask not hermetic in 12 000m high altitude, and whether molecular sieve oxygen generation system(MSOGS) canVIbe used above 8 500m. These problems are all need molecular biological proof. So we are going to develop a series of studies on the effect of fulminating altitude hypoxia on rats, so that we can provide some new sensitive steady simple subjects for estimation of hypoxia protecting effect and hypoxia therapeutic effect; provide experimental proof for further study on the pathophysiological mechanism of fulminating altitude hypoxia and the protection against fulminating altitude hypoxia; at same time, research the physiological equivalent altitude and altitude physiological equal effect theories on molecular biological level.24 male Wistar rats(provided by military medical academy animal center) were devided randomly into 6 groups(n=4): the ground control group, the 3 000m control group, the fulminating altitude hypoxia group, the group breathing 90% enriched oxygen, the group breathing 100% oxygen, the group breathing 50% enriched oxygen. They were exposed to 12 000m fulminating altitude hypoxia, in the meantime they inhaled oxygen with different concentrations for 30 min. The oxygen concentration was monitored by KANE-MAY oxygen detector (United Kingdom), and the enriched oxygen was provided by DY-84 oxygen-nitrogen mixer. Electrocardiogram was recorded per 5min(NIHON-KOHDEN, JAPAN), and the behavior changes of rats was observed and recorded. They were decapitated after treatment, the tissue samples of kidney were taken for RT-PCR of EPO gene; the tissue samples of cotex of parietal lobe were taken for electron microscopic examination; and the tissue samples of brain for microscopy and for immunohistochemical dying of C-FOS.The main results are as following:1 .About electrocardiogram and heart rate, there are no significant difference among the ground control group, the 3 000m control group, the group breathing 90% enriched oxygen, the group breathing 100% oxygen and the group breathing 50% enriched oxygen. The physiological reactionsVIIto hypoxia are most severe in the fulminating altitude hypoxia group, such as tempestuously struggling, twitching, weakly breathing, dull sight , stopping breath in 2~7min. Sinus arrhythmia, nodal arrhythmia, ventricular premature beats and ventricular escape beats can be observed in the fulminating altitude hypoxia group, stopping beat at last.2. The electron miroscopic changes of nerve cells, neuroglial cells, blood vessels varied with different protection, which shows that the lower the concentration of oxygen they breathed, the severer the ultrastrucrural changes are. The fulminating altitude hypoxia group have the severest ultrastructural changes, with additional changes such as perinuclear cistema dilating, synaptic vesicle

Studies on the Effects of Fulminating Altitude Hypoxia and Enriched Oxygen Protection on Rats

Abstract

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