Abstract
Abstract: :
Purpose: Ciliary Neurotrophic Factor (CNTF) is involved in the survival and regeneration of adult rat retinal ganglion cells. In order to elucidate the sequence of molecular events, present experiments seek the changes in expression of CNTF and its receptor CNTFRα and Leukemia Inhibitory factor receptor (LIFR) after optic nerve transection in adult rat retina. Methods: Optic nerve transection was carried out on the right eye of female Wistar rats (200-250grams). The retinas were isolated one and three days after optic nerve transection. Following fixation and cryoprotection, the retinas were serially sectioned. Retinas were stained immunocytochemically for CNTF, CNTFRα using the avidin biotin immunoperoxidase method. In another group, the retinal ganglion cells were prelabelled with intratectal injection of Fluorogold, five days before optic nerve transection .The retinas were isolated one and three days after optic nerve transection and cryosections were reacted for CNTF, LIFR using the double labeling immunofluorescence method. Astrocytes were labeled with GFAP. Results: In the normal retina, CNTF is present only on identifiable astrocytic endfeets. Following optic nerve transection, CNTF is localized additionally on the cells in the Ganglion cell layer (GCL). CNTFRα were localized on the cells in the GCL but were absent from astrocytes. Following optic nerve transection, there was increase in the intensity of immunolabelling of the CNTFRα receptor in cells in the GCL.LIFR were present both in the normal and optic nerve transected retinal ganglion cells. Conclusions: CNTF immunoreactivity increases on the astrocytic endfeet following optic nerve transection and similarly CNTFRα intensity increases on the cells in the GCL suggesting the dependency of receptor upregulation on these cells. In all probability these cells are the retinal ganglion cells.
Keywords: regeneration • retinal degenerations: cell biology • retinal glia