Increased NCAM-180 immunoreactivity and maintenance of L1 immunoreactivity in injured optic fibers of adult mice.
The injury related expression of two axon-growth promoting cell adhesion molecules (CAMs), NCAM-180 which is developmentally downregulated and L1 which is regionally restricted, were compared in optic fibers in the adult mouse. The neuron-specific isoform of NCAM (NCAM-180) is present at very low levels in unlesioned adult optic axons. At 7 days after nerve crush, immunoreactivity was strongly and uniformly increased in optic axons within the nerve and throughout retina. Reactivity in surviving axons had returned to control levels at 4 weeks. To induce regrowth of adult retinal ganglion cell axons retinal explants were placed in culture. Strong NCAM-180 staining was observed on these regenerating optic axons. The neuronal cell adhesion molecule L1 is restricted to retina and to the unmyelinated segment of the optic nerve near the optic nerve head in unlesioned adult animals. Following nerve crush, L1 immunoreactivity was retained within retina and proximal nerve and novel staining was detected in the more distal segment of the optic nerve up to the lesion site where it persisted for at least eight months. The capacity of optic fibers to show increased NCAM-180 immunoreactivity and maintain L1 expression after a lesion may explain why these fibers exhibit relatively good potential for regeneration.
Becker
C G
CG
Department of Developmental and Cell Biology, University of California, Irvine, CA 92697-2275, USA.
Becker
T
T
Meyer
R L
RL
D000818:Animals; D019084:Fluorescent Antibody Technique, Indirect; D007150:Immunohistochemistry; D039841:Leukocyte L1 Antigen Complex; D008562:Membrane Glycoproteins / Q000032:analysis / Q000378:metabolism; D051379:Mice; D009409:Nerve Crush; D009412:Nerve Fibers / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D019006:Neural Cell Adhesion Molecules / Q000032:analysis / Q000378:metabolism*; D009900:Optic Nerve / Q000166:cytology / Q000378:metabolism* / Q000473:pathology*; D020221:Optic Nerve Injuries / Q000378:metabolism* / Q000473:pathology; D009924:Organ Culture Techniques; D020033:Protein Isoforms / Q000032:analysis / Q000378:metabolism; D012160:Retina / Q000166:cytology / Q000378:metabolism*
D039841:Leukocyte L1 Antigen Complex; D008562:Membrane Glycoproteins; D019006:Neural Cell Adhesion Molecules; D020033:Protein Isoforms