Manganese-enhanced MRI of the DBA/2J mouse model of hereditary glaucoma.

Calkins DJ, Horner PJ, Roberts R, Gradianu M, Berkowitz BA
Invest Ophthalmol Vis Sci. 2008 49 (11): 5083-8

PMID: 18552381 · PMCID: PMC2586056 · DOI:10.1167/iovs.08-2205

PURPOSE - To test the hypothesis that manganese-enhanced magnetic resonance imaging (MEMRI) is a sensitive approach for measuring of age-related ocular changes in experimental pigmentary glaucoma.

METHODS - Four groups of light-adapted mice were studied using MEMRI: young (2-3 months), C57BL/6 (negative controls), and DBA/2J mice and aged (10-11 months) C57BL/6 and DBA/2J mice. In all mice, eye perimeter, optic nerve head width, iridocorneal angle, ciliary body area, and total and inner retinal thickness, and a surrogate of retinal ion regulation (intraretinal uptake of manganese) were assessed from MEMRI data and compared. Axon counts were obtained from optic nerves harvested from MEMRI-assessed eyes.

RESULTS - As the C57BL/6 and DBA/2J mice aged, differential and significant changes in ocular perimeter, retinal thickness, iridocorneal angle, ciliary body area, and optic nerve head width were readily measured from MEMRI data (P < 0.05). In C57BL/6 mice, only inner retinal thickness and perimeter were correlated. In DBA/2J mice, ocular perimeter was correlated with total and inner retinal thickness, ciliary body area, optic nerve head width, and iridocorneal angle. Comparison of young and aged mice revealed a subnormal intraretinal manganese uptake (P < 0.05) in aged DBA/2J mice, but not in aged C57BL/6 mice. Manganese uptake did not correlate with the ocular perimeter. Axon density in the optic nerve correlated with MEMRI-measured optic nerve head width (P < 0.05).

CONCLUSIONS - These studies provide a baseline of noninvasive MEMRI-detectable changes associated with age in a common animal model of hereditary glaucoma that may be useful in the longitudinal evaluation of therapeutic success.

MeSH Terms (16)

Animals Axons Ciliary Body Disease Models, Animal Follow-Up Studies Glaucoma, Open-Angle Magnetic Resonance Imaging Manganese Mice Mice, Inbred C57BL Mice, Inbred DBA Optic Disk Reproducibility of Results Retina Severity of Illness Index Trace Elements

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