Cell division and cellular morphology of the chick retinal pigmented epithelial cells in culture. A time-lapse analysis

OBJECTIVE: To investigate the patterns of cell division, movement and shape during early stages of development of the chick embryo retinal pigmented epithelial (RPE) cells and to evaluate the morphology of dissociated embryonic cells with regard to their proliferation capacity.

METHODS: We conducted this study at the Department of Histology and Embryology, Celal Bayar University, Manisa, Turkey, between 2002 and 2003. We isolated the cells from chick embryos. We analyzed the images of the embryonic cells originated from neuroepithelia using a computer-based time-lapse acquisition system attached to a differential interference contrast microscope.

RESULTS: Retinal pigmented epithelial cells, despite being dissociated, depict a colony-type growth. Cells in the periphery of the colony and those outside the colony showed a tendency to proliferate and migrate and retained contact with the neighboring cells during division. Characteristics of cytokinesis were separation from the neighboring cell while retaining an attachment point, became rounded, moved up and started to shake and ascend to disseminate to the substrate to complete the division. The round-up stage was non-significantly shorter when the cell was closer to the center of the colony. Cells that were in the periphery of, or outside the colony had a round-up time of over one hour while cytokinesis-to-adhesion time was around 5 minutes. However, when we found the cells in the center of the colony, the times were half-an-hour and 1.5 hours for the daughter cells, a 2-fold difference between daughter cells with regard to the duration of attachment.

CONCLUSION: Cell division, migration and proliferation are complex procedures influenced by growth factors, cell adhesion, matrix molecules underneath and the signal mechanisms and can be studied in detail using time-lapse microscopy, immunohistochemistry and confocal microscopy.