Effect of crocin on expression of SIRT1/PGC-1α in hippocampus under hypoxia at high altitude in rats

Objective To observe the effect of crocin pretreatment on the learning memory ability, the ultrastructure and SIRT1/PGC-1α expression in hippocampus under hypoxia at high altitude in rats. Methods 96 male SD rats were randomly divided into Hypoxia model group and Hypoxia treatment group with 48 in each.The group rats in treatment group were injected with Crocin once daily(50 mg/kg) and the model group were injected with the same dose of 0.9%NaCl for 3 days, and then they were shifted to high altitude under hypoxic environment and then the samples were taken at 1 d, 3 d, 5 d, 7 d. Morris water maze test was used to observe learning and memory behaviors of rats.The level of SIRT1/PGC-1α protein was detected by Western blot and the level of mRNA was detected by RT-PCR. Results Compared with the model group (1d(37.55±1.34)s, 3d(46.51±6.19)s, 5d(42.12±2.73)s), treatment group showed significant less time in looking for platform in Morris water maze experiment at (1d(33.58±2.23)s, 3d(30.19±3.35)s and 5d(37.10±1.48)s; all P 0.05). Western blot showed that the protein expression levels of SIRT1 and PGC-1α in hippocampus of rats were higher in treatment group (1d(0.72±0.02), (0.72±0.02); 3d(0.76±0.03), (0.75±0.021); 5d(0.54±0.03), (0.74±0.01)) than those in control group (1d(0.53±0.04), (0.62±0.04); 3d(0.15±0.02), (0.13±0.02); 5d(0.23±0.03), (0.21±0.02); all P 0.05). Conclusion Crocin pretreatment can ameliorate mitochondrial damage and improve the ability of learning and memory under hypoxia at high altitude in rats, which may be achieved through increased expression of SIRT1 and PGC-1α in the hippocampus. Key words: Crocin; High altitude; Hypoxia; Hippocampus; SIRT1/PGC-1αsignal pathway