Figure 6. Immunofluorescence staining of cryosections from 6 day cocultured explants. Antibodies against glial fibrillary acidic protein (GFAP; red) and cellular retinaldehyde-binding protein (CRALBP; green) were used. Confocal images revealed an increased expression of GFAP and a decreased CRALBP expression in the neuroretinal external layers. Müller cell processes crossed the outer limiting membrane (OLM; arrows). The cell bodies of GFAP+ astrocytes remained in the nerve fiber layer (NFL; asterisk), but the extensions crossed the neuroretina, reaching the outer layers (arrowheads). Scale bar equals 20 µm. Abbreviations: ganglion cell layer (GCL); inner limiting membrane (ILM); inner nuclear layer (INL); outer nuclear layer (ONL).