Study of the role of the low-affinity neurotrophin receptor p75 in naturally occurring cell death during development of the rat retina.

The aim of this study was to examine the tempo-spatial expression of low-affinity neurotrophin receptor p75, or p75(NTR), and its role in the induction of retinal ganglion cell (RGC) apoptosis in the rat retina during development. The cellular distribution of p75 in the retina was demonstrated with immunohistochemistry and double-immunofluorescent staining. Apoptosis in the developing rat retina was detected by DNA gel electrophoresis, and the number of RGCs undergoing apoptosis was estimated by terminal deoxyribonucleotidyl-mediated dUTP-digoxigenin nick end labeling (TUNEL). To localize p75 on apoptotic RGCs, p75 immunofluorescence and TUNEL fluorescent staining was performed on sections with Fluoro-Gold-prelabeled RGCs. p75 immunoreactivities were not detected either on the RGCs or TUNEL-positive cells, whereas Müller cell processes were p75 immunopositive. Thus, it was most unlikely that p75 induced apoptosis of RGCs in the rat retina.