The role of c-fos, p53 and apoptosis in the form deprivation amblyopic chick retina

Purpose. To examine the possible involvement of c-fos, p53 and apoptosis in amblyopic retinal degeneration in chi>:k. Methods. One eye of hatching white leghorn chick of the Washington H&N ;,train received occluder for 2 weeks and the other eye served as control. Chicks wen killed at 2, 7, 14 or 21 day after the end of insult and designated as day 2, 7, 14 and 21. Immunohistochemistry and TUNEL were used to detect c-fos, p53 and nicked DNA. Results. In the control groups, the retinas showed no marked change histopathologically, c-fos immunoreactivity from day 14 in the retinal ganglion c<:ll layer (RGCL), inner and outer nuclear layers (INL & ONL) and inner segments (IS), p53 immunoreactivity from day 2 in the IS only, and scattered TUNEL pos: tive nuclei with ring pattern, characteristic of early apoptosis, in the RGCL and IN only at day 21. In contrast, the amblyopic chick retinas showed loss of RGCs, thirningofthe INL with scattered dense nuclei starting at day 14, no inflammatory cell, c-fos immunoreactivity aa early as day 2 in the RGCL and the inner part of INL, p53 immunoreactivity in the IS at day 2, then in the RGCL and inner part of INL at day 14 and 21, and TUNEL positive nuclei in the same location as p53 plus in the ONL at day 14. Conclusion. Normal and amblyopic retinas showed difference in apoptotic cell death of the inner retina. and the amblyopic retina showed apoptosis of photoreceptor cells, c-fos and p53 may have different role in apoptosis d.iring the natural development of and form deprivation amblyopic chick retina. Further investigations for their roles were warranted. UPGC CUHK 405/95M.