Intercellular adhesion molecule-1 (ICAM-1) in the mouse facial motor nucleus after axonal injury and during regeneration.
Intercellular adhesion molecule 1 (ICAM-1, CD54) is a widely expressed glycoprotein, which plays an important role in leukocyte extravasation and in the interaction of lymphocytes with antigen-presenting cells. In the current study we examined the regulation of ICAM-1 in the mouse facial motor nucleus after facial nerve transection, using immunohistochemistry, confocal laser microscopy and electron microscopy. In the normal facial nucleus ICAM-1 immunoreactivity was restricted to vascular endothelium. Transection of the facial nerve led to a strong and selective upregulation of ICAM-1 on activated microglia. Quantitation of microglial ICAM-1 immunoreactivity revealed a biphasic increase. The first peak 1-2 days post operation paralleling the early stage of microglial activation was followed by a decline at 4-7 days. The second induction of ICAM-1 occurred at day 14 accompanying the period of neuronal cell death and microglial phagocytosis of neuronal debris. Immunoelectron microscopy showed strong ICAM-1 reactivity on the cell membrane of activated microglia at day 2. During the second peak (day 14), ICAM-1 was also observed on lymphocytes adhering to phagocytotic microglia forming aggregates around neuronal debris. No immunolabelling was observed on neurons, astrocytes or oligodendroglia. These data suggest the involvement of ICAM-1 in the adhesion of activated microglia, in their phagocytosis of neuronal debris, and also in the interaction with infiltrating lymphocytes following this injury.
Werner
A
A
Department of Neuromorphology, Max-Planck Institute of Neurobiology, Martinsried, Germany.
Kloss
C U
CU
Walter
J
J
Kreutzberg
G W
GW
Raivich
G
G
D000818:Animals; D000906:Antibodies; D001369:Axons / Q000502:physiology; D019771:Axotomy; D001812:Blood-Brain Barrier / Q000502:physiology; D004730:Endothelium, Vascular / Q000737:chemistry / Q000648:ultrastructure; D005154:Facial Nerve / Q000098:blood supply / Q000166:cytology / Q000502:physiology*; D020220:Facial Nerve Injuries / Q000503:physiopathology*; D005260:Female; D005455:Fluorescent Antibody Technique; D018799:Intercellular Adhesion Molecule-1 / Q000032:analysis* / Q000276:immunology; D051379:Mice; D008815:Mice, Inbred Strains; D017628:Microglia / Q000737:chemistry / Q000648:ultrastructure; D008854:Microscopy, Electron; D009046:Motor Neurons / Q000737:chemistry* / Q000648:ultrastructure; D009416:Nerve Regeneration / Q000502:physiology*
D000906:Antibodies; D018799:Intercellular Adhesion Molecule-1