Diffusion tensor imaging of visual pathway abnormalities in five glaucoma animal models

Max K. Colbert, Leon C. Ho, Yolandi van der Merwe, Xiaoling Yang, Gillian J. McLellan, Samuel A. Hurley, Aaron S. Field, Hongmin Yun, Yiqin Du, Ian P. Conner, Carlos Parra, Muneeb A. Faiq, John H. Fingert, Gadi Wollstein, Joel S. Schuman, Kevin C. Chan

    Research output: Contribution to journalArticlepeer-review

    Abstract

    PURPOSE. To characterize the visual pathway integrity of five glaucoma animal models using diffusion tensor imaging (DTI). METHODS. Two experimentally induced and three genetically determined models of glaucoma were evaluated. For inducible models, chronic IOP elevation was achieved via intracameral injection of microbeads or laser photocoagulation of the trabecular meshwork in adult rodent eyes. For genetic models, the DBA/2J mouse model of pigmentary glaucoma, the LTBP2 mutant feline model of congenital glaucoma, and the transgenic TBK1 mouse model of normotensive glaucoma were compared with their respective genetically matched healthy controls. DTI parameters, including fractional anisotropy, axial diffusivity, and radial diffusivity, were evaluated along the optic nerve and optic tract. RESULTS. Significantly elevated IOP relative to controls was observed in each animal model except for the transgenic TBK1 mice. Significantly lower fractional anisotropy and higher radial diffusivity were observed along the visual pathways of the microbead- and laser-induced rodent models, the DBA/2J mice, and the LTBP2-mutant cats compared with their respective healthy controls. The DBA/2J mice also exhibited lower axial diffusivity, which was not observed in the other models examined. No apparent DTI change was observed in the transgenic TBK1 mice compared with controls. CONCLUSIONS. Chronic IOP elevation was accompanied by decreased fractional anisotropy and increased radial diffusivity along the optic nerve or optic tract, suggestive of disrupted microstructural integrity in both inducible and genetic glaucoma animal models. The effects on axial diffusivity differed between models, indicating that this DTI metric may represent different aspects of pathological changes over time and with severity.

    Original languageEnglish (US)
    Article number21
    JournalInvestigative Ophthalmology and Visual Science
    Volume62
    Issue number10
    DOIs
    StatePublished - Aug 2021

    Keywords

    • Diffusion tensor imaging
    • Glaucoma
    • Intraocular pressure
    • Magnetic resonance imaging
    • Optic neuropathy
    • Visual pathway

    ASJC Scopus subject areas

    • Ophthalmology
    • Sensory Systems
    • Cellular and Molecular Neuroscience

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