Cell death in cultured dorsal and ventral chick wing bud epithelia.

We have examined the fate of cultured stage 20 and 25 dorsal and ventral wing bud epithelia and have found evidence that the requirements of apical ectodermal ridge and nonridge limb ectoderms for in vitro survival are different. As previously reported for the apical ectodermal ridge (Boutin and Fallon, '84), dorsal and ventral ectoderms were extensively necrotic after 12 hours of culture in serum-containing medium. The survival of dorsal and ventral limb epithelia at 18 hours was not improved by a collagen substratum, 10% Nuserum, epidermal growth factor, nerve growth factor, multiplication-stimulating activity, insulin, or insulin, transferrin, and selenium. This is in contrast to our observations on the ridge which remains vital for at least 24 hours in insulin or insulin, transferrin, and selenium.