Purchase this article with an account.
C Ethier, A Read, D Chan; 3D Actin Structure in Normal and Glaucomatous Outflow Pathway . Invest. Ophthalmol. Vis. Sci. 2002;43(13):1019.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: Actin structure in cultured trabecular meshwork cells differs between normal and glaucomatous cell lines. Here we describe F-actin architecture in whole tissue, specifically cells of the lining endothelium of Schlemm's canal and juxtacanalicular tissue, in normal and age-matched glaucomatous human eyes. Methods: Enucleated fresh eyes were microdissected to expose the inner and outer walls of Schlemm's canal. Outflow pathway tissues were triply labelled with rhodamine-conjugated phalloidin, Sytox, and polyclonal anti-laminin IgG (secondary antibody: Cy5 conjugated anti-IgG), for visualization of F-actin, nuclei, and basal lamina. Confocal laser microscopy was used to optically section the outer and inner walls of Schlemm's canal, and the JCT. Results: Inner wall cells in normal eyes showed a very prominent peripheral F-actin band midway between the apex and base of the cell, with a few fine actin filaments penetrating into the cell's interior (Figure, showing labelled F-actin and nuclei). View OriginalDownload SlideView OriginalDownload Slide Moving basally, the F-actin distribution became more random, resulting in a basal cortical network in inner wall cells. JCT cells showed an apparently isotropic, random F-actin network. Outer wall cells showed central actin stress fibres and near-complete absence of a peripheral F-actin band. In glaucomatous eyes (n = 2 pairs to date), the F-actin of inner wall cells was more disordered, with few peripheral actin bands and apparently more cell-cell connections by central fibres. However, we rarely saw cross-linked actin networks (CLANs) in normal or glaucomatous eyes. Frank openings were seen in the laminin under the inner wall in all eyes. Conclusion: F-Actin distribution is markedly different between inner and outer wall cells in normal eyes, and is in turn different than the distribution in cultured Schlemm's canal endothelial cells. These differences are likely attributable to mechanical forces. Preliminary data suggests that actin distribution in glaucoma inner wall cells is qualitatively different than that in normal inner wall cells, which may have important implications for the biomechanics of the inner wall of Schlemm's canal.
This PDF is available to Subscribers Only