Abstract: Objective To investigate the effects of chronic hypobaric hypoxia on COX1 protein and oxidative stress in lung tissue. Methods Rats were randomly divided into normoxia group (1 500 m) and hypoxia group (4 300 m). The rats in hypoxia group were take samples after exposure to hypoxia for 30 days. The COX1 protein in lung tissue of rats were determined by Western blot method; HIF-1αlevel in lung tissue and serum, ROS in plasma and SOD, CAT enzyme in lung tissue were determined by ELISA method; PAP of rats were determined by physiological signal acquisition system. Results HIF-1 protein express level in serum and lung tissue of rats in hypoxia group was significantly higher than that of the normoxia group (p<0.01), the content of ROS was significantly lower than that of the normoxia group (p<0.01), the expression of COX1 protein in lung tissues of hypoxia group was significantly decreased (p<0.01), serum total antioxidant capacity were elevated in hypoxia group (p<0.01). Conclusions The effects of chronic hypobaric hypoxia on lung tissue may be caused by direct injury, not only by oxidative stress.

Key words: high altitude, hypobaric hypoxia, oxidative stress, lung tissue, COX1