title: Tracking dendritic shrinkage of retinal ganglion cells after acute elevation of intraocular pressure.
abstract: OBJECTIVE
  To investigate dendritic changes of retinal ganglion cells (RGCs) and the rate of dendritic shrinkage after retinal ischemia induced by acute elevation of intraocular pressure (IOP).
  
  
  METHODS
  After elevating the IOP to 110 mm Hg for 30, 60, 90, and 120 minutes, a confocal scanning laser ophthalmoscope (CSLO) was used to serially image the retinas of the Thy-1 YFP transgenic mice in vivo for 1 to 3 months. Dendritic and axonal arborizations of 52 RGCs were visualized and followed longitudinally. Dendritic field, dendritic branching complexity (modified Sholl analysis), axonal diameter, and cell body area were measured. A total of 426 longitudinal measurements of dendritic field and dendritic complexity were analyzed for estimation of rate of change with linear mixed modeling.
  
  
  RESULTS
  There were no morphologic changes of RGCs after 30 (n = 12) or 60 (n = 12) minutes of ischemia. After 90 minutes of ischemia (n = 19), 78.9% of RGCs showed progressive loss of dendrites, axon, and cell body, 5.3% had only mild reduction of branching complexity and shrinkage of dendritic field whereas 15.8% showed no morphologic changes. All RGCs lost dendritic and axonal arborizations after 120 minutes of ischemia (n = 9). The rates of reduction of dendritic field were 11.7% per day (95% confidence interval, 5.0%-18.4% per day) after 90 minutes, and 15.1% per day (10.3%-19.9% per day) after 120 minutes of ischemia.
  
  
  CONCLUSIONS
  RGCs demonstrated dendritic shrinkage after 90 to 120 minutes, but not after 30 to 60 minutes of ischemia. In vivo imaging of dendritic changes could provide a sensitive approach to measure the rate of dendritic shrinkage after acute IOP elevation.
authors.affiliation: Department of Ophthalmology and Visual Sciences, Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Zhi-wai
authors.initials: ZW
authors.lastname: Li
authors.forename: Shu
authors.initials: S
authors.lastname: Liu
authors.forename: Robert N
authors.initials: RN
authors.lastname: Weinreb
authors.forename: James D
authors.initials: JD
authors.lastname: Lindsey
authors.forename: Marco
authors.initials: M
authors.lastname: Yu
authors.forename: Lan
authors.initials: L
authors.lastname: Liu
authors.forename: Cong
authors.initials: C
authors.lastname: Ye
authors.forename: Qiaoling
authors.initials: Q
authors.lastname: Cui
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; D001369:Axons / Q000473:pathology; D003712:Dendrites / Q000473:pathology*; D004195:Disease Models, Animal; D019084:Fluorescent Antibody Technique, Indirect; D007429:Intraocular Pressure; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D009798:Ocular Hypertension / Q000150:complications; D015427:Reperfusion Injury / Q000209:etiology / Q000473:pathology*; D012162:Retinal Degeneration / Q000209:etiology / Q000473:pathology*; D012165:Retinal Ganglion Cells / Q000378:metabolism / Q000473:pathology*; D018800:Thy-1 Antigens / Q000378:metabolism; D013997:Time Factors
chemical_list: D018800:Thy-1 Antigens