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Oligodendrocytes but not astrocytes express apolipoprotein E after injury of rat optic nerve
Author(s) -
Stoll Guido,
Mueller Hans Werner,
Trapp Bruce D.,
Griffin John W.
Publication year - 1989
Publication title -
glia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.954
H-Index - 164
eISSN - 1098-1136
pISSN - 0894-1491
DOI - 10.1002/glia.440020306
Subject(s) - apolipoprotein e , wallerian degeneration , biology , neuroglia , glial fibrillary acidic protein , oligodendrocyte , immunocytochemistry , myelin , microglia , astrocyte , peripheral nervous system , pathology , microbiology and biotechnology , central nervous system , endocrinology , neuroscience , immunology , inflammation , medicine , immunohistochemistry , disease
Abstract Apolipoprotein E (apoE), a lipid‐binding glycoprotein involved in transport and metabolism of phospholipids and cholesterol, is synthesized and secreted at elevated rates following transection of mature rat peripheral and central nerves. In the peripheral nervous system (PNS) infiltrating macrophages express apoE during Wallerian degeneration. Following injury of the optic nerve (ON) apoE synthesis is significantly stimulated but the apoE‐expressing cells have thus far not been identified. This study used 1 μm and thin cryosections to identify the cellular source of apoE in transected ON. Serial 1 μm frozen sections were stained by avidin‐biotin‐peroxidase complex immunocytochemistry by using a specific antiserum to apoE and by antibodies that identify different cell types: glial fibrillary acidic protein (GFAP) for astrocytes, 2′,3′‐cyclic nucleotide‐3′ phosphodiesterase (CNP) for oligodendrocytes, and ED1 for macrophages. In normal ON both astrocytes and oligodendrocytes were apoE‐positive. One week after ON transection oligodendrocytes accounted for the majority of apoE‐positive cells, while apoE immunoreactivity had disappeared from astroglial cell bodies and processes. In contrast to the PNS only a few ED1/apoE‐positive macrophages were present in ON 7 days after transection. By using immunogold‐labeled ultrathin crysections apoE could be localized in the Golgi apparatus of oligodendrocytes, indicating synthesis by these cells. Our data suggest that oligodendrocyte‐derived apoE protein may participate in the redistribution of myelin lipids after CNS injury.