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2004
OMIG, Abstract 13
OMIG
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Assessment
of Corneal Toxicity Following Exposure to VigamoxTM or
ZymarTM Using In Vivo Confocal Microscopy and ZO-1 Staining
W M Petroll, HD Cavanagh, JV Jester. Department of Ophthalmology,
University of Texas Southwestern, Dallas, Texas
Purpose:
To determine the effects of short-term exposure to Vigamox and Zymar
on the corneal epithelial surface.
Methods: Studies were performed on 28 New Zealand
White rabbits. In vivo confocal microscopy was used to assess epithelial
morphology in 18 rabbits. Baseline confocal exams were performed
on one eye of each animal. Two weeks later, the eye was bathed with
either Vigamox (n = 6) or Zymar (n = 6) for 3 minutes and rinsed
with BSS; BSS rinsing without antibiotic treatment was used as a
control (n = 6). Immediately following treatment, corneas were examined
using in vivo confocal microscopy. ZO-1 labeling was used to assess
the integrity of the tight junctions between superficial epithelial
cells in 10 rabbits. One eye of each rabbit was bathed with either
Vigamox (n = 5) or Zymar (n = 5) for 3 minutes and rinsed with BSS;
the contralateral aye served as a control (BSS rinse only). Animals
were immediately sacrificed, and corneas were fixed and stained
using rat monoclonal anti-ZO-1. Buttons were imaged using laser
confocal microscopy.
Results: In Vivo Confocal Microscopy: In
the control and Vigamox groups, superficial epithelial cells appeared
similar to baseline images, as indicated by their visible cell borders
and bright nuclei. In contrast, the surface cells in eyes treated
with Zymar appeared smaller, brighter, and had less distinct borders.
Quantitative analysis demonstrated a significant decrease in epithelial
cell area after treatment with Zymar (p<0.05, Two Way Repeated
Measures ANOVA), but not Vigamox or control. This decrease in cell
size suggests a loss of some superficial epithelial cells, which
leads to exposure of the smaller wing cells on the ocular surface.
ZO-1 Labeling: ZO-1 was organized into a continuous linear
pattern along the cell-cell junctions in both the control and Vigamox
groups. In contrast, ZO-1 staining in eyes treated with Zymar showed
regions of dropout, suggesting a loss of superficial calls. Although
other regions showed ZO-1 staining along coil junctions, labeling
was generally weaker than in the control and Vigamox groups.
Conclusions: Overall, the data demonstrate that
following short term exposure to Vigamox, corneal epithelial integrity
and tight junction organization are maintained. In contrast, Zymar
induces damage to the corneal epithelium in this model, as indicated
by a quantitative decrease in surface cell size and loss of normal
ZO-1 staining.
Supported
by Research to Prevent Blindness and Alcon Laboratories.
OMIG
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