title: Efficient estimation of retinal ganglion cell number: a stereological approach.
abstract: Retinal ganglion cells (RGCs) are the only output neurons of the retina, and their degeneration after damage to the optic nerve or in glaucoma is a well established system for studying apoptosis in the central nervous system. Frequently used procedures for assessing RGC number in retinal flat mounts suffer from two problems: RGC densities are not uniform across retinal flat mounts, and density measures may therefore not reflect total number, and flat mounts do not allow efficient use of tissue. To overcome these problems we developed a stereological method for efficiently assessing RGC number in cryostat sections of the retina. We empirically demonstrate that only approximately 1:20 sections need be assessed to accurately estimate the total number of RGCs in the rat retina, providing ample tissue for additional studies in the same retina and saving considerably on more exhaustive sampling strategies. Using this method, we estimate that there are 86,282+/-4759 RGCs in the normal Brown Norway rat retina. These counts match well with estimates of axon counts in optic nerve. In a pilot study of experimental glaucoma, we determined a reduction of RGCs to 53,862+/-4272 (p<0.05). The current technique should prove advantageous to assess neuroprotective strategies in these experimental models.
authors.affiliation: Howe Laboratory of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, 243 Charles Street, Boston, MA 02114, USA.
authors.forename: John B
authors.initials: JB
authors.lastname: Fileta
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.forename: Gina P
authors.initials: GP
authors.lastname: Kwon
authors.forename: Theodoros
authors.initials: T
authors.lastname: Filippopoulos
authors.forename: Yixin
authors.initials: Y
authors.lastname: Ben
authors.forename: Adam
authors.initials: A
authors.lastname: Dobberfuhl
authors.forename: Cynthia L
authors.initials: CL
authors.lastname: Grosskreutz
mesh_terms: D000465:Algorithms; D000818:Animals; D002452:Cell Count / Q000379:methods*; D016923:Cell Death / Q000502:physiology; D005901:Glaucoma / Q000473:pathology; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D009798:Ocular Hypertension / Q000473:pathology; D051381:Rats; D011914:Rats, Inbred BN; D015203:Reproducibility of Results; D012160:Retina / Q000166:cytology* / Q000473:pathology; D012165:Retinal Ganglion Cells / Q000473:pathology / Q000502:physiology*