Poster présenté par Benjamin Buaud, Responsable projet Nutrition à l’ITERG, 11th Biennial Congress ISSFAL, 28 juin - 2 juillet, Stockholm
A. Letondor (1,2,3), B. Buaud (3), C. Vaysse (3), B. Servat (3), S. Layé (1,2), V. Pallet (1,2), S. Alfos (1,2)
1) Univ. Bordeaux, Nutrition et Neurobiologie Intégrée (NutriNeurO), UMR 1286, Bordeaux
2) INRA, NutriNeurO, UMR 1286, Bordeaux
3) ITERG, Institut des Corps Gras, Pessac
Présentation de résultats obtenus dans le cadre des travaux de l’UMT ACTIA ALICE, menés en collaboration avec le Laboratoire de Nutrition et Neurobiologie Intégrée NutriNeurO – UMR INRA 1286 – Université de Bordeaux
Several studies suggested that n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFAs) and most particularly docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are critical for the maintenance of cognitive functions during aging. N-3 LC-PUFAs may modulate brain functions, by binding to nuclear receptors (NRs), and notably the retinoid X receptors (RXRs). RXR is a master regulator that forms heterodimers with numerous NRs such as the retinoic acid receptors (RARs) which are transcription factors that modulate the expression of genes involved in brain synaptic plasticity. Moreover, NRs can also activate cellular signaling pathways such as the mitogen-activated protein kinase (MAPK) pathway in response to their ligands, independently of their transcriptional activity, also leading to modulation of synaptic plasticity. Besides, several studies have reported that retinoic acid (RA), the active metabolite of vitamin A, improves memory performances of aged animals by modulating RARs and RXRs expression in the hippocampus, suggesting that n-3 LC-PUFAs and vitamin A may modulate synaptic plasticity processes in a similar way. Therefore, the aim of the present study was (i) to evaluate in aged rats (13-month-old), the effects of 5-month dietary supplementations with EPA/DHA and/or vitamin A (vs non-supplemented aged rats) on the memory performances evaluated with the paradigm of the Morris water maze, and (ii) to investigate the molecular mechanisms underlying the memory performances by measuring the hippocampal expression of RARs, RXRs, and several protein kinase signaling pathways. Our main results show that EPA/DHA + vitamin A dietary supplementation had beneficial effects on reference memory, associated with a preserved expression level of RXRγ, CAMKII, CREB, AKT and ERK1/2 MAPK in the hippocampus. This study provides original data concerning the combined effects of n-3 LC-PUFAs and vitamin A within the framework of the formulation of a preventive nutrition to delay brain aging.