Lipoic Acid Facilitates Learning and Memory in Aged Mice

Abstract

Lipoic acid (LA) is identified as an antioxidant to scavenge and inactivate free radicals. Although LA has been used as a dietary supplement for a long time, the effect of LA supplement on preventing aged-memory loss haven’t been studied yet. This study aimed to determine whether LA could promote the ability of learning and memory in the aged mice model. There were four groups in this study: aged control group (20 months old C57BL / 6J mice without any dosage), 0.1% LA dosage group (20 months old C57BL / 6J mice), 0.2% LA dosage group (20 months old C57BL / 6J mice), and young control group(3 months old C57BL / 6J mice without any dosage). Cognitive abilities were tested through behavioral tests, and factors related to synaptic plasticity (BDNF, PSD95, p-NMDAR1, p-CAMK II) were detected by Western Blot. In behavioral test, young control group shown a greater capacity in learning and memory than aged control group. Comparing with aged control group, the abilities of passive avoidance and spatial memory and learning in two LA dosage groups were significantly enhanced by using step-down test and Morris water maze respectively. Up-regulated expression of BDNF and higher levels of PSD95, p-NMDAR1, p-CAMKⅡ were observed in both two LA dosage groups and young control group compared with aged control group. Our findings suggest that long-term LA intervention can effectively delay or prevent the decline of learning and memory associated with aging via altered synaptic plasticity.