Reduced expression of NeuroD1 in the neonatal hypoxic-ischemic rat brain is restored by preconditioning.

A.CASTRO; F. LÓPEZ-AGUILERA F; L. SAVASTANO; A. SELTZER; E. MUÑOZ

Universidad de la Punta, Cdad. de la Punta, San Luis.

Congreso; XXVII Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2009

SBCuyo

Reduced expression of NeuroD1 in the neonatal hypoxic-ischemic rat brain is restored by preconditioning. Castro A, López-Aguilera F, Savastano L, Seltzer A and Muñoz E IHEM-CONICET, FCM-UNCuyo, Mendoza. ANPCyT. Email: munoz.estela@fcm.uncu.edu.ar  Preconditioning (PC) is an endogenous mechanism that protects organisms against injury. It promotes the expression of genes involved in neurogenesis. We have induced PC in a neonatal rat brain model of hypoxic-ischemic lesion, and assessed the expression of NeuroD1, a member of the bHLH transcription factor family that is known to determine the fate of specific neuronal cells. For immunohistochemistry at P15, 4% PFA-fixed brain slices were obtained from lesioned (L) (P8 pups with permanent ligature of the right CCA followed by 1-2 min of asphyxia); PC (same as L, but submitted to 3 consecutive sessions of autohypoxia in the previous day) and control (C) (sham operated-non-asphyxiated) animals. L rats showed reactive gliosis (GFAP (+) and Vim (+) astrocytes) while PC animals only exhibited a milder reaction. In C and PC, NeuroD1 (+) signal was observed in the nuclei of the subgranular zone (SGZ) cells of the dentate gyrus (DG), external and internal granule cell layers of the cerebellum with migrating positive cells between both layers and a cluster of cells in the cerebral cortex (CC) close to the IV ventricle. L animals showed a decrease in migrating cells in the cerebellum, and labeled cells in the ipsilateral hippocampus and CC. These preliminary results suggest that neonatal hypoxia-ischemia affects NeuroD1 expression in the brain, and PC prevents these effects.