RESUMO
<p><b>OBJECTIVE</b>To investigate the effect of hypobaric hypoxia (HH)on the cognitive function of mice and the phosphorylation of tau protein in mice brain.</p><p><b>METHODS</b>Forty male mice were randomly divided into 4 groups (n = 10): static control (control) group, 8 hours (8 h) group, 7 days(7 d) group and 28 days(28 d) group, which were exposed to simulated HH equivalent to 5 500 m in an animal decompression chamber for 0 hour, 8 hours, 7 days and 28 days, respectively. Cognitive performances were examined by open field and passive avoidance test, tan phosphorylation was assayed by Western blot.</p><p><b>RESULTS</b>In open field test,the group exposed in hypobaric hypoxia for 28 d showed lower mean velocity (P < 0.05), time in central zone (P < 0.05) was longer than control group. In passive avoidance test 28 d group presented worse performance in both latency time and number of mistakes (P < 0.05) compared with control group. Western blot showed that phosphorylated tau was increased significantly following exposure to HH for 7 d in cortex and 28 d in hippocampus (P < 0.05).</p><p><b>CONCLUSION</b>Tau hyperphosphorylation in brain of mice may play a role in chronic HH-induced cognitive function impairment.</p>
