Artificial metaplasia of pigmented epithelium into retina in tadpoles and adult frogs

Abstract

ABSTRACT The present work was aimed at investigating the possibility and conditions necessary for the artificial transformation of one tissue into another. Experiments were carried out with the pigmented epithelium of the eye in tadpoles and adult frogs of Rana temporaria. Following the removal of the mesenchyme envelopes (or their exfoliation during the experiment), pigmented epithelium transformed into retina under the influence of retina from tadpoles of the same species. This phenomenon was observed both under the cultivation of a piece of retina in a sandwich of pigmented epithelium and the transplantation of pigmented epithelium layers into the eye cavity of tadpoles. Such transformation did not occur in the absence of retinal influence. Metaplasia requires the removal of the mesenchyme envelopes, the action of the retinal agent, as well as preservation of the integrity of the pigmented epithelium layer and subsequent proliferation of its cells. The character of general control mechanisms both maintaining the stability of cell types and leading to their transformation into other cell types is discussed.