Effects of iodoacetic acid on cytoskeleton and adhesiveness of the chick RPE cells in vitro.

The retinotoxic, sulfhydryl-binding drug, iodoacetic acid (IAA), affects embryonic chick retinal pigmented epithelial (RPE) cells grown in primary cultures in a reversible, dose-dependent manner. A dose of 5 X 10(-4) M which produces drastic cell shape changes in about 90 min was chosen to study the effects of IAA on the organization of cytoskeleton and adhesiveness in RPE cells. After treatment of cells with IAA microtubules depolymerize and F-actin becomes redistributed from numerous stress fibers to knob-like aggregates. Vinculin is released from focal contacts and adhesions into the cytosol and, at the same time, adhesiveness of the RPE cells to substratum decreases. Since RPE in vitro is susceptible to the action of IAA, it seems possible that also in vivo some of the retinotoxic effects of IAA might be attributed to its damaging influence on the RPE. Thus, the retinotoxic effects of IAA in vivo cannot be solely attributed to the selective degeneration of photoreceptors by this agent.