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Ultrastructural Changes in the Optic Nerve After Injury and Neurotrophic Factor Treatment
Author(s) -
Vega Giam,
Blagburn Jonathan,
Blanco Rosa
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.707.3
Subject(s) - ciliary neurotrophic factor , axotomy , axon , lesion , optic nerve , neurotrophic factors , pathology , neurotrophin , nerve growth factor , macrophage , glial scar , regeneration (biology) , fibroblast growth factor , nerve injury , biology , medicine , neuroscience , microbiology and biotechnology , astrocyte , central nervous system , in vitro , receptor , biochemistry
We have shown that ciliary neurotrophic factor (CNTF) and fibroblast growth factor (FGF‐2) have strong facilitatory effects on axon regeneration in the adult frog optic nerve after injury. In these nerves, bundles of regenerating axons were associated with astrocytes and macrophage‐like cells. The objective of the present study is to characterize the identity of these cells, and to determine the changes that occur after CNTF or FGF‐2 application. We performed optic nerve crush and applied into the nerve either saline solution or neurotrophic factors. We examined the optic nerves at different timepoints: 48h, one week, and two weeks after axotomy. Electron microscopy was used to characterize the ultrastructure and localization of the macrophages/microglia after injury and neurotrophic treatment. Antibodies against specific macrophage subtypes were used to label these cells in confocal images of different regions of the nerve. We found a large number of macrophage‐like cells at the lesion site, and distally in close proximity to regenerating axons in CNTF and FGF‐2 treated nerves. Significantly fewer cells were present proximal to the lesion. Many of these macrophage‐like cells at, and distal to, the lesion were ED‐1‐positive in both CNTF and FGF‐2 treated nerves. Both M1 (Arginase‐positive) and M2 (CD‐86‐positive) subtypes were identified. We are currently quantifying the distribution of these cell subtypes at different timepoints and nerve regions after injury. In conclusion, the application of CNTF and FGF‐2 affects the number and the distribution of macrophage subtypes after optic nerve injury and during optic nerve regeneration.