Effects of cytochalasins and colchicine on the ultrastructure of migrating corneal epithelium.

To determine the effects of cytochalasins and colchicine on the ultrastructure of migrating corneal epithelium of the rat, abraded corneas healing in organ culture were cultured for 30 min in the presence of these cytoskeletal-perturbing drugs. Transmission and scanning electron microscopy of these corneas indicate the following. (1) Cytochalasins B (1 microgram/ml of medium) and D (0.1 microgram/ml of medium) caused drastic alteration in structure of cells of the leading edge only. Stratified layers of cells behind the leading edge were unaffected. This observation may indicate that it is the cells of the leading edge which have a rapid turnover of actin filament formation during epithelial sheet movement. (2) Both cytochalasins caused surface blebs or zeiotic processes to form on cells of the leading edge. The shape of the processes caused by the cytochalasins differed, however. Actin filaments accumulated in the cytoplasm under the zeiotic processes. (3) Colchicine had no effect on the ultrastructure of migrating epithelium.