Diffuse axonal damage, myelin impairment, astrocytosis and inflammatory response following microinjections of NMDA into the rat striatum.

White matter damage and inflammatory response are important secondary outcomes after acute neural disorders. Nevertheless, a few studies addressed the temporal outcomes of these pathological events using non-traumatic models of acute brain injury. In the present study, we describe acute inflammatory response and white matter neuropathology between 1 and 7 days after acute excitotoxic striatal damage. Twenty micrometer sections were stained by hematoxylin and eosin technique for gross histopathological analysis and immunolabed for neutrophils (anti-mbs-1), activated macrophages/microglia (anti-ed1), astrocytes (anti-gfap), damaged axons (anti-betaapp) and myelin basic protein (MBP). Recruitment peak of neutrophils and macrophages occurred at 1 and 7 days post-nmda injection, respectively. Diffuse damaged axons (beta-app + end-bulbs) were apparent at 7 days, concomitant with progressive myelin impairment and astrocytosis. Further studies using electron microscopy and blockers of inflammatory response and glutamatergic receptors should be performed to confirm and address the mechanisms of white matter damage following an excitotoxic lesion.