title: Retinal ganglion cells resistant to advanced glaucoma: a postmortem study of human retinas with the carbocyanine dye DiI.
abstract: OBJECTIVE
  The present study was conducted to examine whether the morphology of the retinal ganglion cells is altered in advanced glaucoma. Perikaryal, axonal, and dendritic alterations were monitored in glaucoma-resistant retinal ganglion cells by postvitam application of the fluorescent dye DiI.
  
  
  METHODS
  The retinas of four amaurotic glaucomatous eyes and four normal eyes enucleated after death were used in this study. The retinas were freed from surrounding tissue, prepared as flatmounts on a nitrocellulose filter, and fixed overnight in 4% paraformaldehyde. The retinal ganglion cells were labeled by introducing crystals of the fluorescent carbocyanine dye DiI, into the optic fiber layer. This dye diffuses along membranes of ganglion cell axons, completely labeling them and their cell bodies and dendrites. Further characterization of the retinas and optic nerves included hematoxylin-eosin and van Gieson histochemical staining as well as immunohistochemistry against glial fibrillary acidic protein.
  
  
  RESULTS
  Because of the advanced stage of the disease, the retinas were almost completely depleted of ganglion cells, which had degenerated and therefore could not be stained. The few remaining ganglion cells were considered to be resistant to glaucoma. They showed drastic morphologic alterations, such as abnormal axonal beading, the cell bodies were normal in size but had irregular silhouettes or swellings, and there were fewer dendritic bifurcations. The size of the dendritic trees was smaller, implicating pruning of smaller dendritic branches. Glial cells were also detected immunocytochemically indicating their involvement in the pathologic course of glaucoma.
  
  
  CONCLUSIONS
  The data suggest that the few ganglion cells that survive the elevated intraocular pressure associated with loss of visual function display morphologic changes that are manifested both on the cell body and on their intraretinal processes, including axons and dendrites.
authors.affiliation: Department of Experimental Ophthalmology, University Eye Hospital Münster, Domagkstrasse 15, D-48149 Münster, Germany.
authors.forename: Mitrofanis
authors.initials: M
authors.lastname: Pavlidis
authors.forename: Tobias
authors.initials: T
authors.lastname: Stupp
authors.forename: Rita
authors.initials: R
authors.lastname: Naskar
authors.forename: Cani
authors.initials: C
authors.lastname: Cengiz
authors.forename: Solon
authors.initials: S
authors.lastname: Thanos
mesh_terms: D000328:Adult; D001369:Axons / Q000473:pathology; D001766:Blindness / Q000209:etiology; D002232:Carbocyanines; D002470:Cell Survival; D003712:Dendrites / Q000473:pathology; D015353:Eye Enucleation; D005456:Fluorescent Dyes; D005901:Glaucoma / Q000150:complications*; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006801:Humans; D007429:Intraocular Pressure; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology; D009901:Optic Nerve Diseases / Q000209:etiology / Q000473:pathology*; D012164:Retinal Diseases / Q000209:etiology / Q000473:pathology*; D012165:Retinal Ganglion Cells / Q000473:pathology*
chemical_list: C035005:3,3'-dihexadecylindocarbocyanine; D002232:Carbocyanines; D005456:Fluorescent Dyes; D005904:Glial Fibrillary Acidic Protein