Preserved memory capacities in aged Lou/C/Jall rats

Although memory impairments are a hallmark of aging, the degree of deficit varies across animal models, and is likely to reflect different states of deterioration in metabolic and endocrinological properties. This study investigated memory-related processes in young (3-4 months) and old (24 months) Sprague-Dawley rats (SD), which develop age-linked pathologies such as obesity or insulin-resistance and Lou/C/Jall rats, which do not develop such impairments. In short- and long-term memory recognition tasks, old Lou/C/Jall rats were never impaired whereas old SD rats were deficient at 1 and 24h latencies. The expression of N-methyl-d-aspartate receptors (NMDAR)-mediated synaptic plasticity in CA1 hippocampal networks shifted towards lower activity values in old Lou/C/Jall rats whereas long-term potentiation was impaired in age-matched SD rats. Age-related decrease in NR2A subunits occurred in both strains, extended to NR2B, NR1 and GluR1 subunits in older animals (28 months) but only in SD rats. Therefore, the Lou/C/Jall rats can be considered as a model of healthy aging, not only in terms of its preserved metabolism, but also in terms of cognition and synaptic plasticity.