Kainate excitotoxicity in the spinal cord of female young and adult rats

SISTI MS; NISHIDA F; ZANUZZI CN; PORTIANSKY EL

Congreso; XXXIII Congreso Anual Sociedad Argentina de Investigación en Neurociencias; 2018

The understanding of the pathophysiology of the devastating effects of spinal cord injury have been the aim of numerous investigations using different experimental models. Kainic acid (KA) is a glutamate-agonist widely used to induce excitotoxic lesions in different regions of the CNS. Neuroprotective effects of estrogens against glutamate-induced excitotoxic assault are well-known. We have previously reported that aged female rats showed higher neuronal counting and serum prolactin levels in comparison to young female rats. In the present work, we aimed to compare the functional and histological changes between young (y) and adult (a) female rats after an intraparenchymal injection of 1 mM KA into the C5 segment of the spinal cord. Animals were grouped as KA-y/KA-a (injected with 1mM KA) and sham-y/sham-a (injected with saline). Histopathology and clinical evaluation using motor and sensitive tests (ladder rung walking test, suspension from wire pole mesh, von Frey nociceptive assay) were analyzed at day 0, 1, 2, 3 and 7 post injection (pi). KA-y/KA-a showed a significant impairment of their performance in the motor and sensitive tests at day 2 and 3 pi in comparison to sham-y/sham-a. A reduced excitotoxic effect was observed in KA-a rats in comparison to KA-y rats. Controversial data are reported in reference to vulnerability to excitotoxicity during aging. More detailed studies are required to determine whether sex hormones and prolactin are involved in the reduction of the neurotoxic effects of KA observed in aged females.