engleski

The ability of the epithelium of diencephalic origin to differentiate into cells of the ocular lens

After the discovery that in adult salamanders following lensectomy a new, functional lens develops by transdifferentiation (cell type conversion) of previously depigmented epithelial cells of the iris (Wolffian lens regeneration), this phenomenon has been intensively studied by various experimental approaches. During the last two decades it was shown that pleiomorphic aggregates of atypical lens cells (lentoids) differentiated in reaggregates of dissociated cells of the chick neural retina and in spread cultures of the pigmented epithelium of the iris and retina, of the neural retina and pineal gland of chick embryo. The neural retina in human fetuses and adults also displayed this capacity. We showed that lentoids developed at a low incidence in renal isografts of rat embryonic shields or isolated embryonic ectoderm and of lensectomized eyes of rat fetuses, as well as in organ cultures of rat embryonic shields in chemically defined media. The addition of transferrin significantly increased the incidence of differentiation of lentoids in explants. In both renal isografts and explants in vitro a continuous transformation of retinal epithelial cells into atypical lens cells was observed. In renal isografts lentoids were also observed from the ependyma of the brain ventricle. All tissues having the capacity to convert into lens cells belog to the diencephalon in a broad sense. Evolutionary aspects of this feature are discussed.

lens; lentoids; diencephalon; transdifferentiation; rat

nije evidentirano