Figure 7.

Retinal gliosis in a control F344/N rat. (A) Focally extensive hypercellular lesion (H&E stain) centered within the retina at the optic disc area (arrow). (B) Higher magnification of the lesion showing an expanded optic nerve fiber layer containing cells with elongated nuclei (arrows); fibrillar, eosinophilic cytoplasm; and indistinct cell membranes. (C) Labeling with anti-glial fibrillary acidic protein (GFAP) reveals glial processes (arrows) of reactive Müller cells extending from the outer plexiform layer through the inner nuclear layer and inner plexiform layers abutting the inner limiting membrane. GFAP-stained cells within the optic nerve fiber layer were concluded to be those of traversing Müller cells as well as astrocytes (parallel to the optic nerve fibers), and not the proliferating cells of interest, due to the meager staining immediately adjacent to the nuclei of the cells forming the lesion. (D) Staining with vimentin also clearly identifies glial processes (arrows) of Müller cells and processes within the plexiform, inner nuclear, and optic nerve fiber layers, and inner limiting membrane. Cross-section of the area of interest within the optic nerve fiber layer shows scattered punctate, nonspecific, positive staining with vimentin that was not interpreted to identify the cells of interest.