Biological markers to study the morphological modification induced by perinatal asphyxia

RODOLPHO KOLLIKERS-FRERS; JUAN PABLO LUACES; MARIA INES HERRERA; MICAELA MARTINEZ; BORDET, SOFÍA; CHEVALIER, GUENSON; KUSNIER CARLOS; GABRIEL CAO; LUCAS UDOVIN; NICOLAS TORO-URREGO; KOBIEC, TAMARA; GRACIELA OTTAVIANO; PÉREZ-LLORET, SANTIAGO; OTERO-LOSADA, MATILDE; CAPANI, FRANCISCO

Busan

Congreso; International Congress of microscopy; 2024

International Federation of societies for microscopy, IFSM

Statement of the Problem: Perinatal asphyxia (PA), a neurodevelopmental impairment that leads to neonatal mortality and is a determinant factor for short- and long-term disorders. Since pathophysiological mechanisms triggered by PA are not still totally unveiled, we investigated the changes in the cytoskeleton organization, synapse, and astrocytes in the nervous tissue. Methodology & Theoretical Orientation: For this study, we used a well-established murine model of PA [1]. After one, 2, 4 and 6 months of severe PA (21 min) rats were sacrificed and their brains were analyzed by combining photooxidation, conventional electron microscopy and electron tomography 3-D reconstruction techniques in two areas hypoxia sensible: neostriatum and hippocampus [1]. Findings: After one month of PA, we found an increase in the F-actin staining in neostriatal and hippocampal dendritic spines together with some filopodia-likes structures, a typical embryonic type of spines in photooxidated tissue [2] [Fig 1 A). In contrast, after second month of PA, spines were less consistent stained. In addition, we observed an increment of marker for neuronal and glial dysfunction such as GFAP, neurofilament and MAP-2 [3]. These modifications were more clearly defined after 4 months of PA [3]. After 6 months of PA postsynaptic densities (PSDs) in neostriatum were highly modified. Using three-D reconstructions and electron tomography we were able to find clear signs of degeneration in the asphyctic PSDs (Fig 1 B and C) [3] Conclusion & Significance: Therefore, we hypothesize that the cytoskeletal changes induced by PA in the rat CNS could lead to the severe modifications in synapse and related structures that trigger neuronal damage. In addition, electron tomography, 3-D reconstruction and photooxidation contributed to dissect critical alterations generated by PA that are not easily displayed using conventional microscopic techniques. These findings might contribute to generate new therapeutic tools.