Morphological changes induced by colchicine in the chick optic cup in early stages of development. A stereological study

Abstract

In this study chick embryo optic cups at HH stage 13 of development were analyzed under normal conditions and after inoculation with colchicine for 1, 2, 4, and 8 h. Several changes were seen after these periods of treatment: 1) modifications of the structure, with thicker regions in the cup and a general decrease in the total volume according to the duration of exposure to the drug (about 4 times less than normal, 5,035 x lo3 ym3 vs 1,334 x lo3 ym3 after 8 h of treatrnent); 2) enlargement of the ventricular cavity and its closure, due to failure of approximation of retina1 and pigmentary layers; 3) failure of lens development, with delay and impairment of pit formation and deformation of al1 structures; lens volume was less than normal (about 4 times less, 2,148 x 103 pm3 vs 658 x lo3 pm3. after 8 h of treatment); 4) a general segregation of the cells making up the structure, principally in the more active proliferating zones. The local alterations found are described