Abstract: AIM: To investigate the protective effects of Vitamin E on learning and memory in a mouse model of Alzheimer' s disease (AD) and the mechanisms.METHODS: Mice were intragastric administrated with D-galactose (D-gal ) and sodium nitrite (NaNO2 ) or vehicle, and divided into two main groups which received Vitamin E (28 and 280 IU kg) at two different time points:either at the same time of administration, or 2 h after D-gal and NaNO2 dosing.After that, animals were trained and tested learning and memory abilities using the SMG-2 water maze.The changes of AChE and nuclear factor (NF)-κB were detected to explore the mechanism of Vitamin E' s protective effects on learning and memory deficits.RESULTS: Mice administrated with Vitamin E at the same time of D-gal and NaNO2 dosing showed a significant decrease in escape latency[F(3, 56)=6.959 on day 1;F (3, 56)=6.689 on day 2;F (3, 56)= 17.379 on day 3;F(3, 56)=13.391 on day 4;P<0.05], accompanied with significant reduction of MDA[F(3, 28)=11.235, P<0.05] and AChE activity[F(3, 28)=29.431, P<0.05], increase of SOD activity [F(3, 28)=7.372, P<0.05].Vitamin E also decreased Aβ and NF-κB expressions in the cerebral cortex of AD mice model (P<0.05).However, mice receiving Vitamin E 2 h after D-gal and NaNO₂ dosing can not reverse the learning and memory deficits.CONCLUSION: Preventive administration of Vitamin E could remarkably prevent the learning and memory impairment, the machnism may be to increase the activity of SOD, reduce the activity of AChE, the levels of MDA and the expressions of Aβ and NF-κB in the brain.

Key words: Alzheimer' s disease, Vitamin E, learningand memory deficits, mice