Hippocampal chronic changes after spinal cord injury: glial reactivity and neurogenesis reduction

JURE, I; LABOMBARDA, F; PIETRANERA L; DE NICOLA, AF

Congreso; 2 nd Federation of Latin American and Caribbean Neuroscience Societies; 2016

The main components of the neurogenic niche are astrocytes and microglialcells, which regulate neurogenesis under normal and neurophatologicalconditions leading to functional consequences for learning and memory. Althoughcognitive impairments were reported in patients after spinal cord injury (SCI),only few studies consider remote changes in brain structures which are notrelated with sensory and motor cortex. Thus, we examined hippocampalneurogenesis and glial reactivity by stereological assessment after threedifferent intensities of thoracic spinal cord compression in rats. Sixty daysafter compression injury, we observed concomitant decrease in BBB scores,rotarod performance and spare tissue volume. This study described that thenumber of active microglial cells and reactive astrogliosis increased in alldentate gyrus sub-regions after severe SCI. The density of active microgliaincreased in the hilus whereas astrogliosis was developed in the molecularlayer after moderate SCI. No changes were observed in the mildly injured rats.  Neurogenesis and the number of hilarneurons were reduced after severe SCI, while only neurogenesis decreased in themoderately injured group. No differences were found in the measured parametersafter mild injury. Theseresults suggest that glial response and neurogenesis associate with injuryintensity. Furthermore, reactive astrogliosis and microglial activation couldbe responsable for the behaviouralimpairments exhibited in humans.