Nishida Fabián
National University of La Plata (UNLP), Argentina
Title: Functional, histopathological and immunohistochemical changes induced by intraparenchymal injection of Kainic acid in the rat cervical spinal cord
Biography
Biography: Nishida Fabián
Abstract
Kainic acid (KA) is an analogue of the neurotransmitter glutamate and causes extensive neuronal network damage and early irreversible loss of neuronal activity. The present work was aimed at evaluating motor and sensory performance of rats and analysing morphometric parameters and immunohistochemical reactivity of spinal cord neurons after intraparenchymal KA injection. Animals were injected either with 0.75 mM, 1 mM or 1.25 mM of KA at the C5 segment of the cervical spinal cord. Motor and sensory performance were evaluated at days 0, 1, 2, 3 and 7 post-injection (pi) and compared with those of saline-treated and non-operated animals. Three animals were euthanized at each time point. All KA-treated animals showed a significant impairment at the motor and sensory tests for the ipsilateral forelimb in a concentration-dependent manner in comparison to control groups. Neuronal cell count showed a significant loss of neurons at C4, C5 and C6 cervical segment when compared with those of saline-treated and non-operated animals. The contralateral side of the cervical segments in KA-treated rats remained unchanged. Immunohistochemical technique showed a similar immunoreactivity pattern with those observed in brains of Alzheimer´s diseases patients. Some improvement at the motor and sensory tests was observed in animals injected with 0.75 mM and 1 mM KA. Moreover, a mild increase in the neuronal count at the damaged segments was also recorded. Functional improvements registered in the motor and sensory tests by day 7 pi may be a consequence of a neuron repairing mechanism triggered soon after the KA excitotoxic effect.