Abstract: To explore the protective role of conjugated linoleic acid (CLA) in hypoxia injury, forty SD rats were divided randomly into four groups, including positive CLA groups (1%CLA group, 1%CLA + hypoxia group) and negative control groups (control group, control + hypoxia group). Both the positive CLA groups and negative control groups were fed with 1%CLA and distilled water respectively and each animal received a constant daily dose of 20ml/kg body weight for four weeks consecutively. After the treatment, the hypoxic groups were exposed eight hours daily at the altitude of five thousand meters for fifteen consecutive days. The ratios of activities of SOD, GSH-PX and the contents of MDA in serum were determined respestively. The results showed that, under the hypoxic condition, the ratio of viscera weight to body weight increased obviously(p<0.05). While the activities of SOD and GSH-PX decreased markedly(p<0.05) and the contents of MDA increased significantly(p<0.05) in rat serum. The ratio of viscera weight to body weight, the activities of SOD, GSH-PX, and the contents of MDA in 1% CLA hypoxic group showed no obvious difference in comparison with that of control group. In conclusion, 1%CLA had obvious protectiver olei nh ypoxia injury.

Key words: conjugated linoleic acid, hypoxia injury, protection