The effect of exposure to normbaric hypoxia on the body weight in rats

为了确定大鼠的体重是否在标准气压缺氧环境下会减轻,本实验将12只5周龄Wis-tar大鼠移高至海拔2260m并使之持续暴露于含10%O2的低氧小低压舱内(相当于在海拔5000m)20日。在基线每5日测一次体重。由于标准气压缺氧环境可影响血循环功能,所以在大鼠移入高原前后20天,分别对其肺动脉压和血红蛋白浓度进行了测定。基线处体重为(222.4±20.7)g,而与基线处相比。大鼠体重在移高5、10、15和20天后明显下降,分别下降了(4.88±SD)%、(7.67土SD)%、(11.05±SD)%和(11.9±SD)%,差异显著(P<0.05)。基线处大鼠的平均肺动脉压为(21.3±2.5)mmHg,低氧暴露20天后肺动脉压明显增高[(45.3±5.8)mmHg,P<0.001]。血红蛋白浓度在基线处的平均值为(14.5±3.2)g/L,而在低氧暴露20天后明显增加[(22.6±5.4)g/L,P<0.001]。该结果显示,模拟高海拔可使大鼠体重明显下降,这与先前报道的人体试验结果相似。结果也进一步说明,标准气压下持续的低氧环境对肺动脉压和血红蛋白浓度可产生实质性影响。

To determine whether a norm baric hypoxia cause＇s weight loss, 12 male 5-week old Wistar rats raised at an altitude of 2 260m were continuously exposed to a small hypoxic chamber with 10% O2, which is equivalent to 5 000m, for 20 days. Body weight was measured at baseline and every five days. Since normobaric hypoxia could also affect vascular function, pulmonary arterial pressure and hemoglobin concentration were measured before（n=5） and after the 20-day hypoxic exposure.Baseline body weight was （222.4±20.7）g （mean±SD）. Body weight, when compared to baseline,decreased progressively by （4.88±SD）%, （7.67±SD）%,（11.05±SD）%, and （11.9±SD）% at 5,10,15,and 20 days, respectively（P〈0.05-0.01）. The mean pulmonary arterial pressure at baseline was （21.3±2.5）mmHg, and increased significantly after 20-day hypoxic exposure （45.3±5.8）mmHg）（P〈0.001）. Hemoglobin concentration at baseline was （14.5±3.2）g/L and increased significantly to （22.6±5.4）g/L （P〈0.001）after the 20-day hypoxic exposure. The present results appear that simulated altitude exposure in rats leads to a significant loss of body weight, which is similar to that previously reported for humans. Further, continuous normobaric exposure appears to produce substantial effects on PAP and Hb.