MITOSIS IN DEVELOPING RABBIT RETINA - AN IMMUNOHISTOCHEMICAL STUDY

The proliferation of cells in the embryonic and postnatal rabbit retin a was studied with the MIB-1 antibody which demonstrates the Ki-67 ant igen. Already at embryonic day 15 there were postmitotic cells (i.e. c ells that do not stain with the MIB-1 antibody) in the basal part of t he neuroblastic cell mass which are presumably the differentiating gan glion cells. After the formation of an inner plexiform layer at around embryonic day 25, postmitotic cells were seen in the proximal part of neuroblastic cell mass (presumably amacrine cells) as well as in the ganglion cell layer. Proliferating cells accumulated distal to the lay er of postmitotic cells and their number gradually decreased towards t he pigmented epithelium. At birth, proliferation ceased in the central parts of the retina but in the peripheral parts it continued for 7 da ys although rare cells could be seen for up to 15 days. After the form ation of the outer plexiform layer, the proliferating cells in the out er nuclear layer accumulated close to the outer plexiform layer wherea s the postmitotic cells (the differentiating photoreceptors) did so at the distal part of outer nuclear layer. Some cells in the middle of t he inner nuclear layer (presumably the Muller cells) and some cells in the ganglion cell layer or nerve fiber layer (presumably the astrocyt es) proliferated for the longest period of time. (C) 1997 Academic Pre ss Limited