Astrocyte Reactivity Is Associated with Decreased Levels of N-Acetyl-Aspartate in the Absence of Neurodegeneneration in the Rat Brain

Maria-Angeles Carrillo-de Sauvage¹, ², Lucile Ben Haim¹, ², Julien Valette¹, ², Carole Escartin¹, ²

A decrease in the concentration of the neuronal metabolite NAA is usually interpreted as neuronal degeneration or dysfunction, although the molecular basis is still unknown. Reactive astrocytes are associated with degenerating or dysfunctional neurons and could indirectly modulate brain metabolite concentrations. In this study, we aimed at dissecting the MRS signature associated with astrocyte reactivity per se, using a model of selective astrocyte activation through lentiviral gene transfer of the cytokine CNTF, in absence of detectable effects on neurons. We show that, contrary to the classic interpretation, a decrease in NAA can occur in absence of neurodegeneration