Assessment transcallosal Diaschisis in a model of focal cerebral ischemia in rats.

To evaluate transcallosal changes after a local ischemic injury in rats by using the monoclonal marker anti-NeuN (Mouse anti-neuronal nuclei). Twenty-eight adult, male, Wistar rats were subjected to focal injury in the right hemisphere. The technique used was the experimental model of focal ischemic injury through intraluminal suture of the middle cerebral artery. Analyses were made for the five groups: after the lesion (control), at 24 h, 96 h, 10 days and 20 days. Exofocal neuronal damage was inferred from neuronal immunoreactivity changes to NeuN. In the cortex contralateral to the lesion, immunoreactivity was diminished. This finding was most notable in the supra-granular sheets 24 h post ischemia. After 96 h, there was a generalized diminishment of the inmmunoreactivity in the supra and infra-granular sheets. At 10 and 20 days, the tissue recovered some immunoreactivity to NeuN, but there were some changes in the VI layer. The immunoreactive changes to NeuN support the process of inter-hemispheric diaschisis. Changes in immunoreactivity could indicate metabolic stress secondary to the disruption in connectivity to the site of lesion.