Lithium and memantine improve spatial memory impairment and neuroinflammation induced by β-amyloid 1-42 oligomers in rats

Alzheimer's disease (AD) is the most common cause of dementia in the elderly. The main hallmarks of this disease include progressive cognitive dysfunction and an accumulation of soluble oligomers of beta-amyloid (AD) 1-42 peptide. In this research, we show the effects of lithium and memantine on spatial memory and neuroinflammation in an A beta 1-42 oligomers-induced animal model of dementia in rats. A beta 1-42 oligomers were administered intrahippocampally to male wistar rats to induce dementia. Oral treatments with memantine (5 mg/kg), lithium (5 mg/kg), or both drugs in combination were performed over a period of 17 days. 14 days after the administration of the A beta 1-42 oligomers, the radial arm-maze task was performed. At the end of the test period, the animals were euthanized, and the frontal cortex and hippocampus were removed for use in our analysis. Our results showed that alone treatments with lithium or memantine ameliorate the spatial memory damage caused by A beta 1-42. The animals that received combined doses of lithium and memantine showed better cognitive performance in their latency time and total errors to find food when compared to the results from alone treatments. Moreover, in our study, lithium and/or memantine were able to reverse the decreases observed in the levels of interleukin (IL)-4 that were induced by A beta 1-42 in the frontal cortex. In the hippocampus, only memantine and the association of memantine and lithium were able to reverse this effect. Alone doses of lithium and memantine or the association of lithium and memantine caused reductions in the levels of IL-1 beta in the frontal cortex and hippocampus, and decreased the levels of TNF-alpha in the hippocampus. Taken together, these data suggest that lithium and memantine might be a potential therapy against cognitive impairment and neuroinflammation induced by A beta 1-42, and their association may be a promising alternative to be investigated in the treatment of AD-like dementia. (C) 2017 Elsevier Inc. All rights reserved.