title: A Period of Controlled Elevation of IOP (CEI) Produces the Specific Gene Expression Responses and Focal Injury Pattern of Experimental Rat Glaucoma.
abstract: We determine if several hours of controlled elevation of IOP (CEI) will produce the optic nerve head (ONH) gene expression changes and optic nerve (ON) damage pattern associated with early experimental glaucoma in rats.
  
  
  
  The anterior chambers of anesthetized rats were cannulated and connected to a reservoir to elevate IOP. Physiologic parameters were monitored. Following CEI at various recovery times, ON cross-sections were graded for axonal injury. Anterior ONHs were collected at 0 hours to 10 days following CEI and RNA extracted for quantitative PCR measurement of selected messages. The functional impact of CEI was assessed by electroretinography (ERG).
  
  
  
  During CEI, mean arterial pressure (99 ± 6 mm Hg) and other physiologic parameters remained stable. An 8-hour CEI at 60 mm Hg produced significant focal axonal degeneration 10 days after exposure, with superior lesions in 83% of ON. Message analysis in CEI ONH demonstrated expression responses previously identified in minimally injured ONH following chronic IOP elevation, as well as their sequential patterns. Anesthesia with cannulation at 20 mm Hg did not alter these message levels. Electroretinographic A- and B-waves, following a significant reduction at 2 days after CEI, were fully recovered at 2 weeks, while peak scotopic threshold response (pSTR) remained mildly but significantly depressed.
  
  
  
  A single CEI reproduces ONH message changes and patterns of ON injury previously observed with chronic IOP elevation. Controlled elevation of IOP can allow detailed determination of ONH cellular and functional responses to an injurious IOP insult and provide a platform for developing future therapeutic interventions.
authors.affiliation: The Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States.
authors.forename: John C
authors.initials: JC
authors.lastname: Morrison
authors.affiliation: The Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States.
authors.forename: William O
authors.initials: WO
authors.lastname: Cepurna
authors.affiliation: The Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States.
authors.forename: Shandiz
authors.initials: S
authors.lastname: Tehrani
authors.affiliation: The Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States.
authors.forename: Tiffany E
authors.initials: TE
authors.lastname: Choe
authors.affiliation: The Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States 2Glaucoma Service, NIHR Moorfields Biomedical Research Centre, London, United Kingdom.
authors.forename: Hari
authors.initials: H
authors.lastname: Jayaram
authors.affiliation: The Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States.
authors.forename: Diana C
authors.initials: DC
authors.lastname: Lozano
authors.affiliation: Devers Eye Institute, Portland, Oregon, United States.
authors.forename: Brad
authors.initials: B
authors.lastname: Fortune
authors.affiliation: The Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States.
authors.forename: Elaine C
authors.initials: EC
authors.lastname: Johnson
mesh_terms: D000818:Animals; D018797:Cell Cycle Proteins / Q000096:biosynthesis / Q000235:genetics*; D004195:Disease Models, Animal; D004596:Electroretinography; D005500:Follow-Up Studies; D005786:Gene Expression Regulation; D005901:Glaucoma / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D009898:Optic Disk / Q000000981:diagnostic imaging / Q000378:metabolism*; D012313:RNA / Q000235:genetics*; D051381:Rats; D011914:Rats, Inbred BN; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D018797:Cell Cycle Proteins; D012313:RNA