|
|
||||||||
From the Departments of Medicine and Physiology, Cardiovascular Research Institute, University of California, San Francisco, California.
PURPOSE. To investigate the involvement of aquaporin (AQP)-1 in lens epithelial cell water permeability and maintenance of lens transparency in experimental models of cataract formation.
METHODS. Comparative studies were performed on wild-type versus AQP1-null mice. Osmotic water permeability was measured in calcein-stained epithelial cells in intact lenses from fluorescence changes in response to osmotic gradients. Lens water content was measured by gravimetry using kerosenebromobenzene density gradients, and from wet/dry weight measurements. Lens transparency was measured by contrast analysis of transmitted grid images. Cataract formation was induced in vitro by incubation in high-glucose solutions and in vivo by acetaminophen toxicity.
RESULTS. Immunofluorescence showed AQP1 expression in wild-type mice in epithelial cells covering the anterior surface of the lens. AQP1 deletion did not alter baseline lens morphology or transparency, though basal water content was
3% greater (P < 0.001). AQP1 deficiency reduced plasma membrane water permeability in lens epithelium by 2.8 ± 0.3-fold (P < 0.0001). Loss of lens transparency was accelerated by more than 50-fold in AQP1-null lenses bathed in a 55-mM glucose solution for 18 hours. At 4 hours after acetaminophen administration in 3-methylcholantrenetreated mice, lens opacification was seen in none of the six wild-type mice and in six of six AQP1-null mice.
CONCLUSIONS. Lens AQP1 facilitates the maintenance of transparency and opposes cataract formation.
This article has been cited by other articles:
![]() |
R. Gerometta, A. C. Zamudio, D. P. Escobar, and O. A. Candia Volume change of the ocular lens during accommodation Am J Physiol Cell Physiol, August 1, 2007; 293(2): C797 - C804. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |