Docosahexaenoic acid restores learning and memory functions altered by acute manganese intoxication in mice

Manganese (Mn) is a trace essential element and neurotoxic at higher levels, provokes cognitive impairment via oxidative stress, neuroinflammation, and neurotransmitter disarrangement. Therefore, this study aimed to investigate whether DHA, a major omega-3 polyunsaturated fatty acid that is known to have potent neuroprotective effects, rescues deficits in learning and memory induced by Mn in mice. DHA was given daily for 6 days at the beginning of acute manganese intoxication to adult Swiss mice. Spatial learning, short-term memory long-term memory and executive function was assessed with the Morris Water Maze test and Puzzle Box tests. Mnexposure caused a significant impairment in all the neuropsychological areas, spatial memory function, and inhibitory avoidance retention and prolonged escape latency time (ELT) than problem-solving ability. Most importantly, DHA co-treatment completely ameliorated the cognitive deficiency, including changes in learning curves and memory retention. These results reinforce the idea that DHA protects against Mn-induced neurotoxicity, at least in part due to its antioxidative, anti-inflammatory and synaptoprotective effects. In conclusion, DHA might be a potential nutritional intervention for preventing or reversing heavy-metal induced learning and memory deficits.