Impairment and restoration of the endothelial blood-brain barrier in the rat cerebral infarction model assessed by expression of endothelial barrier antigen immunoreactivity

Endothelial barrier antigen (EBA) can be used to detect the blood-brain barrier in the central nervous system of rats. This study investigated the temporal profile of antigen expression in cerebral vessels after infarction and assessed the relationship between re-establishment of this antigen in newly formed vessels and astrocytes around these vessels. Rats were subjected to cerebral ischemia for 2 h by the intraluminal thread method, then killed after 1, 3, 7, 14 and 28 days. Perfusion-fixed paraffin-embedded brains were immunostained for detection of EBA and glial fibrillary acidic protein (GFAP) by the streptavidin-biotin-peroxidase complex method. EBA immunostaining in vessels in the infarcted lesion was reduced at day 1 and had almost disappeared by day 3. Newly formed vessels were found from day 3, but were not stained at day 7. However, these new vessels were weakly stained at day 14 and definitely stained at day 28. GFAP immunostaining was completely negative around these proliferating vessels. The temporal profile of disappearance and re-expression of EBA in cerebral infarcted lesion may be associated with aggravation and improvement of brain edema, although barrier permeability was not explored in this study. The expression of this antigen has no relationship to the formation of astrocyte/endothelial contacts.