Ultrastructural changes associated with dexamethasone-induced ocular hypertension in mice.

Published

Journal Article

To determine whether dexamethasone (DEX)-induced ocular hypertension (OHT) in mice mimics the hallmarks of steroid-induced glaucoma (SIG) in humans, including reduced conventional outflow facility (C), increased extracellular matrix (ECM), and myofibroblasts within the outflow pathway.Osmotic mini-pumps were implanted subcutaneously into C57BL/6J mice for systemic delivery of DEX (3-4 mg/kg/d, n = 31 mice) or vehicle (n = 28). IOP was measured weekly by rebound tonometry. After 3 to 4 weeks, mice were euthanized and eyes enucleated for ex vivo perfusion to measure C, for electron microscopy to examine the trabecular meshwork (TM) and Schlemm's canal (SC), or for immunohistochemistry to examine type IV collagen and α-smooth muscle actin. The length of basement membrane material (BMM) was measured along the anterior-posterior extent of SC by electron microscopy. Ultrastructural changes in BMM of DEX-treated mice were compared against archived human SIG specimens.Dexamethasone increased IOP by 2.6 ± 1.6 mm Hg (mean ± SD) over 3 to 4 weeks and decreased C by 52% ± 17% versus controls. Intraocular pressure elevation correlated with decreased C. Dexamethasone treatment led to increased fibrillar material in the TM, plaque-like sheath material surrounding elastic fibers, and myofibroblasts along SC outer wall. The length of BMM underlying SC was significantly increased in mice with DEX and in humans with SIG, and in mice decreased C correlated with increased BMM.Dexamethasone-induced OHT in mice mimics hallmarks of human SIG within 4 weeks of DEX treatment. The correlation between reduced C and newly formed ECM motivates further study using DEX-treated mice to investigate the pathogenesis of conventional outflow obstruction in glaucoma.

Full Text

Duke Authors

Cited Authors

  • Overby, DR; Bertrand, J; Tektas, O-Y; Boussommier-Calleja, A; Schicht, M; Ethier, CR; Woodward, DF; Stamer, WD; Lütjen-Drecoll, E

Published Date

  • July 15, 2014

Published In

Volume / Issue

  • 55 / 8

Start / End Page

  • 4922 - 4933

PubMed ID

  • 25028360

Pubmed Central ID

  • 25028360

Electronic International Standard Serial Number (EISSN)

  • 1552-5783

International Standard Serial Number (ISSN)

  • 0146-0404

Digital Object Identifier (DOI)

  • 10.1167/iovs.14-14429

Language

  • eng