Figure 4. Cryosections of TgN S334ter rat retina studied at post-natal day 35. All sections were immunostained for green fluorescent protein (GFP; green) and retinal cell nuclei were counter-stained blue with DAPI. A-C: Illustrates images from rats from the group treated at post-natal day 21 with intravitreal injection of GDNF-secreting (and GFP-expressing) mouse embryonic stem cells (mES cells). Plates A-C demonstrates integration of GFP-expressing mES cells into the retina. The asterisks mark clumps of mES cells. Some are seen migrating (arrow in C) from the innermost retina toward the outer retina, and extending between the outer nuclear layer (ONL) and inner nuclear layer (INL). D: Illustrates a mock injection eye from the group treated with intravitreal injection of sham injection of PBS, and shows autofluorescence in the retinal pigment epithelium and photoreceptor outer segments (arrowhead). Abbreviations: inner nuclear layer (INL); outer nuclear layer (ONL). Scale bars represent 50 μm.