Glial fibrillary acidic protein expression in postnatal development of WAG/Rij rat retina

Abstract

Introduction: WAG/Rij rat is an experimental model of retinal degenerative diseases intensifying with age. Degeneration begins in the photoreceptor cells layer, followed by disappearance of photoreceptor cells, migration of the pigment epithelium and disorganization of remaining retinal layers. However, the age of onset of the degeneration is unknown. The destroyed neurons of retina are usually replaced by glial cells. A typical marker for several types of glial cells is the glial fibrillary acidic protein (GFAP). Aim of the Work:The aim of the study is to determine postnatal changes of GFAP expression in retina of WAG/Rij rats. Material and Methods: WAG/Rij rats of both sexes and different ages: 1, 10, 15, 20, 30, 60, 180, 360 postnatal days (P) (n =3 for each age) were taken. The immunohistochemical analysis of GFAP expression in the retina of WAG/Rij rats was performed and the expression area was measured. Results: Expression of GFAP in the retina is detected from P1 to P20 as a brown staining in the internal limiting membrane or as a brown lines on the inner retina. On P30 the glial fibrillary acidic protein is already detected in significant quantities in almost all layers of the retina of the experimental rats. From P60 to P360 the expression of GFAP in the retina of the WAG/ Rij rats is more pronounced and increases in direct proportion with the age. Conclusion: It was found that GFAP expression in the retina of WAG/Rij rats increases in direct proportion to the age. The increasing GFAP expression in the retina of the WAG/Rij rats starting from the 30th postnatal day indicates an intensification of destructive processes in retinal neurons with age and their replacement by Müller cells.