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目的探索增氧呼吸器对严重急性低压缺氧的防护作用及氧自由基的影响。方法30只雄性新西兰大白兔随机分为3组,对照组(Con)暴露在海拔400m(西安市的平均海拔高度)不佩戴增氧呼吸器;急性低压缺氧组(H)暴露在模拟海拔8500m环境180min,不佩戴增氧呼吸器;急性低压缺氧呼吸器防护组(P)暴露在模拟海拔8500m环境180min,佩戴增氧呼吸器。各组动物均于进舱时、气压降至海拔8500m即刻、30、60、120、180min抽取动脉血0.5mL进行实时血气分析,并于实验结束时抽取动脉血2mL进行超氧化物歧化酶(SOD)活性和丙二醛含量(MDA)测定。结果H组各时间点PaO2、SaO2及终点SOD活性均低于Con组,P组则均高于H组,两组血气均于8500m30min时降至最低。血清MDA浓度H组显著高于Con组,P组显著低于H组,各组间比较均P<0.001。结论佩戴增氧呼吸器能提高严重急性低压缺氧时PaO2、SaO2及SOD活性,从而在一定程度上防护缺氧所致的自由基损害。
Objective To explore the protective effect of aerobic respirator on severe acute hypobaric hypoxia and the effect of oxygen free radicals. Methods Thirty male New Zealand white rabbits were randomly divided into three groups. The control group (Con) exposed to altitude of 400 m (average altitude in Xi’an) did not wear aerobic ventilator. The acute hypobaric hypoxia group (H) exposed to simulated altitude of 8500 m Environment 180min, do not wear aerobic respirator; Acute hypobaric hypoxia respirator group (P) exposed to simulated altitude 8500m environment 180min, wear respirator. At the time of entering the tank, the air pressure dropped to 8500m immediately, 0.5mL arterial blood was drawn at 30, 60, 120 and 180min for real-time blood gas analysis. At the end of the experiment, 2mL arterial blood was drawn for superoxide dismutase (SOD ) Activity and malondialdehyde (MDA) content. Results The activities of PaO2, SaO2 and end-point SOD in group H were lower than those in group Con in group H and group H in group P, respectively. The blood gas in both groups decreased to the lowest at 8500m30min. Serum MDA concentration in H group was significantly higher than that in Con group, P group was significantly lower than that in H group, P <0.001. Conclusion Oxygen-breathing respirator can improve the activity of PaO2, SaO2 and SOD during severe acute hypobaric hypoxia, thus protecting the free radical damage induced by hypoxia to a certain extent.