Abstract: Objective    To study the effects of different hypoxia stress on the construction of high altitude pulmonary edema (HAPE) model. Methods    Total of 60 SD rats were randomly divided into 3 groups: the control group (at an altitude of 400 m), the hypobaric oxygen chamber group (simulating altitude of 6 000 m, and hypoxia stress for 48 h), and the field hypoxia group (at an altitude of 4 200 m, 28 days of hypoxia stress), 20 animals in each group. By detecting lung tissue dry-wet ratio, morphological and pathophysiological characteristics, expressions of key genes including aquaporin-1 (AQP-1) and vascular endothelial growth factor (VEGF), and oxidative stress level, the effect of different hypoxia stress on the establishment of HAPE model in SD rats was compared. Results    Compared with the control group, the results of hypobaric oxygen chamber group and the field hypoxia group were as follows: the pulmonary artery pressure of the rats in the two groups increased significantly (P<0.01), while the oxygen partial pressure and oxygen saturation decreased significantly (both P<0.01); the lung tissue moisture content in both groups increased significantly (P<0.01). The lung tissue morphology of the control group was normal under a light microscope and an electron microscope, while the alveolar wall and alveolar septum of the two experimental groups were significantly widened under a light microscope, with a large number of red blood cells and inflammatory cells overflowing, and the obvious edema of alveolar septum was observed under a light microscope. The mRNA and protein levels of AQP-1 in the lung tissues of the two experimental groups were significantly higher than those of the control group, while the mRNA and protein levels of VEGF were significantly lower than those of the control group (all P<0.01). There were low GSH-Px and SOD levels and high MDA level in the serum of the two experimental groups. Conclusion     Both the hypobaric oxygen chamber simulating the hypoxia stress at an altitude of 6 000 m for 48 h and the field hypoxia stress at an altitude of 4 200 m for 28 d effectively can construct the HAPE model of SD rats, and the hypobaric oxygen chamber for constructing the SD rat model of HAPE was more dominant.

Key words: Acute pulmonary edema at high altitude, Hypoxia, Hypobaric oxygen chamber;