Effects of aging and diabetes on the hippocampus. Protection by estradiol and fluoxetine treatments.

BEAUQUIS J; ROIG P; DE NICOLA AF; SARAVIA F

Frauenchiemsee, Alemania.

Workshop; Route 28 Summits in Neurobiology - Adult neurogenesis, stem cells and aging disorders.; 2006

Route 28, Fundación Volkswagen.

We have studied the influence of estrogen administration on brain plasticity in aging mice. Using BrdU injection protocols we found a pronounced reduction of BrdU positive cells in the granular cell layer (GCL) of untreated old mice and a marked increase after animals were exposed to estrogens. Untreated old mice also showed astrocytosis, increased neuronal content of lipofuscin (measured by autofluorescence) and hilar neuronal loss. Estrogen completely reverted these changes. Estrogen behaved as a neuroprotectant to the aging hippocampus. Using BrdU labeling and immunohistochemistry for neuronal markers we have found reduced neurogenesis in the subgranular zone and GCL of diabetic animals. We also found a reduced content of BDNF mRNA in the dentate gyrus of diabetic mice. Treatment with fluoxetine, which is clinically effective for depression, corrected both the reduction of neurogenesis and the reduction of BDNF expression in the GCL of diabetic animals. We think this could be a novel approach for the treatment of diabetes and a new evidence of the neuropathology present in this disease. Both aging and diabetes share many pathological features that are not yet clearly explained.