缺氧预适应小鼠缺氧耐受性、运动耐力及肺功能的改变

Changes of hypoxia tolerance, exercise tolerance and pulmonary function of mice under the condition of hypoxic preconditioning

目的:观察缺氧预适应对小鼠缺氧耐受性、运动耐力及缺氧条件下小鼠肺功能的影响。方法:实验于2003-12/2004-12在解放军第四军医大学病理生理学实验室进行。①常压耐缺氧时间的测定:取昆明小鼠20只随机分为2组(n=10),正常对照组在正常氧环境(体积分数为0.21的氧)中,缺氧预适应组小鼠在低压低氧条件下(体积分数为0.21的O2与体积分数为0.08的O2交替循环4次,每种氧浓度下持续15min)复制缺氧预适应模型,将两组小鼠置于正常氧环境下1h后,观察其在缺氧中存活时间。②负重游泳实验:分组和处理同前,将两组小鼠置于正常氧环境下1h后,小鼠尾根部负荷7%体质量的铅丝,置游泳箱中游泳,观察小鼠游泳至力竭时间。③耐寒实验:分组和处理同前,将两组小鼠置于正常氧环境下1h后,记录小鼠在-8℃的条件下的存活时间。④肺水含量测定:取昆明小鼠20只随机分为4组(n=5),正常对照组和缺氧预适应组处理同前,单纯缺氧组小鼠置于体积分数为0.07的O2缺氧6h,缺氧预适应+缺氧组:缺氧预适应后1h,置于体积分数为0.07的O2缺氧6h。测定各组小鼠肺组织湿重/干重比值。⑤肺血管通透性测定:分组和处理同肺水含量测定实验,检测各组小鼠的肺灌洗液/血清吸光度比值。结果:经补充后100只小鼠进入结果分析。①常压缺氧耐受时间:缺氧预适应组长于正常对照组犤(20.5±2.4),(14.6±3.7)min,P<0.05犦。②负重游泳时间:缺氧预适应组长于正常对照组犤(173.9±37),(112.3±41)min,P<0.05犦。③耐寒时间:缺氧预适应组长于对照组犤(63.4±7.2),(50.1±4.8)min,P<0.05犦。④肺水含量和肺血管通透性:单纯缺氧组小鼠肺组织湿重/干重和肺灌洗液/血清吸光度比值高于正常对照组(P<0.05);缺氧预适应组和缺氧预适应+缺氧组小鼠明显低于单纯缺氧组(P<0.05)。结论:缺氧预适应可提高小鼠缺氧耐受性、运动耐力及耐寒能力,增强缺氧小鼠肺功能。

AIM： To study the effect of hypoxic preconditioning on mice hypoxia stamina, exercise tolerance and pulmonary function in hypoxic condition. METHODS： The experiment was carried out in the pathophysiology laboratory of the Fourth Military Medical University of Chinese PLA from December 2003 to December 2004. （1） Determination of hypoxia time at normal pressure： Twenty Kunming mice were divided randomly into 2 groups （n=10）. The mice in the normal control group were put into environment with normal oxygen （with the volume fraction of 0.21）. The mice experienced hypoxic preconditioning were gotten by the model of repetitive hypoxia under hypobaric hypoxia circumstance （subjecting mice to four cycles of 15 minutes of 0.08 O2 -15 minutes of 0.21 O2）. After putting these two groups of mice in the normal oxygen environment for 1 hour, then observes the survival time of them in hypoxic condition. （2） Swimming experiment with a heavy load： The grouping method and treating processes of the other experiments were the same as the first one. After putting two groups of mice into normal oxygen environment for one hour, tied the lead wires equal to 7% body mass of each mouse to their tails, and then put them in the swimming box to swim, the swimming time was observed. （3） Cold resistant experiment： The grouping method and treating processes of the other experiments were the same as the first one. After putting these two groups of mice in the normal oxygen environment for 1 hour, then the survival time of each mouse were recorded under -8 ℃ condition. （4） Measurement of water content in lung： Twenty Kunming mouse were selected and divided randomly into 4 groups （n=5）. The disposal of mice in the normal control group and hypoxic preconditioning group was the same as before. The pure oxygen hypoxia group mice were subjected in 0.07 O2 for 6 hours. The mice in the oxygen hypoxia preconditioning ＋ oxygen hypoxic group were subjected in 0.07 O2 for 6 hours after hypoxic preconditioning for 1 hour. Ratio of wet weight to dry. weight of pulmonary organization of mice in every group was detected.（5） Measurement of pulmonary vascular permeability： The grouping and processing was the same as the experiment of measurement of pulmonary water content. The ratio of cleaning solution from lung of each mouse to absorbance （A） of serum was measured. RESULTS： After compensation 100 mice were involved in the result analysis. （1） Hypoxia time at normal pressure： It was longer in the hypoxic preconditioning group than that in the normal control group [（20.5±2.4）, （14.6±3.7） minute, P 〈 0.05]. （2） Swimming time with a heavy load： It was longer in the hypoxic preconditioning group than that in the normal control group [ （173.9±37）, （ 112.3±41 ） minute ,P 〈 0.05]. （3） Cold resistant time： It was longer in the hypoxic preconditioning group than that in the control group [（63.4±7.2）, （50.1±4.8） minute,P 〈 0.05]. （4） Pulmonary water content and pulmonary vascular permeability： Ratio of wet weight to dry weight of pulmonary organization and ratio of cleaning solution from lung of each mouse to A of serum of mice in pure hypoxia group were higher than those in the normal control group （P 〈 0.05）. It was lower significantly in the hypoxic preconditioning group and hypoxic preconditioning＋hypoxia group than that in the pure hypoxia group （P 〈 0.05）. CONCLUSION： The hypoxic preconditioning can improve mice hypoxia stamina, exercise tolerance and cold-resistant capacity and reinforce pulmonary function of mice.