呼吸不同浓度氧气对兔高空暴露的防护作用

目的 观察兔暴露于高空时呼吸不同浓度氧气后的生理变化和组织超微结构改变，探讨分子筛氧源在高空的防护效果。方法 将20只兔随机分为呼吸空气组(A)、呼吸63％富氧气体组(B)、呼吸83％富氧气体组(C)和呼吸纯氧组(D)。各组兔在低压舱内上升到11000m，停留30min，记录心脏区气泡、心电图和客观反应，观察心和脑组织超微结构的变化，肾组织促红细胞生成素(EPO)的表达。结果 空气组心脏区气泡数量明显增加，多数兔出现心律失常；富氧浓度组和纯氧组偶见气泡；随着吸人气氧浓度的增加，脑、心组织超微结构缺氧改变减轻，肾EPOmRNA表达的阳性率降低。结论 呼吸含氧浓度大于80％的富氧气体对高空暴露的机体有明显的防护作用。

Effects of oxygen on rabbits during exposure to high altitude

Objective To observe physiological and ultrastructure changes in rabbits breathing various contents of oxygen during exposure to high altitude. Methods Twenty healthy rabbits were randomly divided into air-breathing group, 63% oxygenbreathing group, 83% oxygenbreathing group and pure oxygen breathing group. All rabbits were exposed to an atmosphere corresponding to an altitude of 11 000m in hypobaric chamber for 30min. The amount of air bubble in the heart and ECG of rabbits were recorded, the ultrastructural changes in the heart and brain were examined, and the expression of kidney erythopoietin (EPO) was also observed. Results The amount of air bubbles in the air breathing group was increased remarkably, and most of the rabbits developed arrhythmia. With the increase of oxygen concentration, the changes in ultrastructure were alleviated and the expression of kidney EPO decreased. Conclusion Oxygenconcentration above 80% could provide obvious protection for rabbits during their exposure to high altitude.