Differentiation of lens and pigment cells in cultures of brain cells of chick embryos.

Dissociated cells of brains (tel- and diencephalons) of 3.5-day-old chick embryos were cultivated in vitro under the cell culture conditions which are known to be permissive for neural retinal cells (NR cells) to transdifferentiate into lens and/or pigmented epithelial cells (PE cells). The differentiation of lentoid bodies (LBs) with lens-specific delta-crystallin and PE cells with melanin granules was observed in such brain cultures. LBs appeared in two different phases, i.e., 2-3 days and 16-30 days of cultivation, and after 40 days of culture these structures were formed in all 60 culture dishes. Sometimes, LBs were observed in foci of PE cells formed during earlier stages of brain cultures. When similar brain cultures were prepared with older embryos of 5-, 8.5-, 14-, and 16-days of incubation, no differentiation of lens and PE cells was observed.