title: Tracking retinal microgliosis in models of retinal ganglion cell damage.
abstract: OBJECTIVE
  To investigate the longitudinal profiles of microgliosis after optic nerve injury induced by optic nerve crush and acute elevation of intraocular pressure (IOP).
  
  
  METHODS
  A confocal scanning laser ophthalmoscope was used to image the retinal microglia of the CX3CR1(GFP/+) transgenic mice in vivo at baseline, 3 days and then weekly for 4 weeks after optic nerve crush (n = 3), and after elevating the IOP to 110 mm Hg for 30 (n = 3) or 60 (n = 3) minutes.
  
  
  RESULTS
  After optic nerve crush, the density of microglia increased by 2.43 ± 0.19-fold at week 1 and then gradually declined with 2.04 ± 0.24-, 1.69 ± 0.25-, and 1.29 ± 0.11-fold increases at week 2, 3, and 4, respectively. Microgliosis followed a similar pattern after acute IOP elevation and the increase in microglia was associated with the duration of IOP elevation. There were 1.35 ± 0.17- and 2.03 ± 0.08-fold increases in microglia at week 1, and 1.15 ± 0.11- and 1.11 ± 0.10-fold increases at week 4, after 30 and 60 minutes of acute IOP elevation, respectively. The morphology of microglia changed from ramified to ameboid form in 1 week, and then returned to ramified form in the subsequent weeks. There was a significant negative association between the number of surviving retinal ganglion cells (RGCs) and the extent of microgliosis during the follow-up period (R² = 0.72, P = 0.004).
  
  
  CONCLUSIONS
  Longitudinal in vivo imaging of the retinal microglia can provide an effective approach to study microgliosis and its association with RGC degeneration.
authors.affiliation: Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, People's Republic of China.
authors.forename: Shu
authors.initials: S
authors.lastname: Liu
authors.forename: Zhi-wai
authors.initials: ZW
authors.lastname: Li
authors.forename: Robert N
authors.initials: RN
authors.lastname: Weinreb
authors.forename: Guihua
authors.initials: G
authors.lastname: Xu
authors.forename: James D
authors.initials: JD
authors.lastname: Lindsey
authors.forename: Cong
authors.initials: C
authors.lastname: Ye
authors.forename: Wing-ho
authors.initials: WH
authors.lastname: Yung
authors.forename: Chi-Pui
authors.initials: CP
authors.lastname: Pang
authors.forename: Dennis Shun Chiu
authors.initials: DS
authors.lastname: Lam
authors.forename: Christopher Kai-shun
authors.initials: CK
authors.lastname: Leung
mesh_terms: D000818:Animals; D005911:Gliosis / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology; D007429:Intraocular Pressure / Q000502:physiology; D008137:Longitudinal Studies; D051379:Mice; D008822:Mice, Transgenic; D017628:Microglia / Q000473:pathology*; D018613:Microscopy, Confocal; D020221:Optic Nerve Injuries / Q000150:complications / Q000473:pathology*; D012165:Retinal Ganglion Cells / Q000473:pathology*