3-DIMENSIONAL AND ULTRASTRUCTURAL ICAM-1 DISTRIBUTION IN THE CHOROID-PLEXUS, ARACHNOID MEMBRANE AND DURAL SINUS OF INFLAMMATORY RATS INDUCED BY LPS INJECTION IN THE LATERAL VENTRICLES

To investigate immunological environment in the cerebrospinal fluid (C SF) system, ultrastructural and three-dimensional localization of inte rcellular adhesion molecule-1 (ICAM-1) was studied in the choroid plex us, arachnoid membrane and dural sinus of LPS-stimulated rats with imm uno-SEM and TEM. The choroid plexus epithelial cells expressed rich IC AM-1 along the microvilli. The arachnoid trabeculae fibroblast-like ce lls demonstrated ICAM-1 expression on both sides facing the subarachno id space moderately. The dural sinus endothelial cells, however, showe d only few ICAM-1 expression and no specific localization. These resul ts suggest that the choroid plexus and arachnoid membrane may play an important mutual role for leukocyte migration in the CSF system, and t hat the CSF system may function in immunoreaction independently of the vascular system with the aid of up-regulated ICAM-1 expression. (C) 1 998 Elsevier Science B.V. All rights reserved.