MULLER CELL EXPRESSION OF GLIAL FIBRILLARY ACIDIC PROTEIN AFTER GENETIC AND EXPERIMENTAL PHOTORECEPTOR DEGENERATION IN THE RAT RETINA

  • 1 January 1984
    • journal article
    • research article
    • Vol. 25  (11) , 1321-1328
Abstract
Glial fibrillary acidic protein (GFAP) is normally found in astrocytes. In the normal rat retina at all ages, only astrocytes stain for GFAP. This staining pattern is also found in RCS rats, with inherited retinal dystrophy, younger than 38 days. Beginning on day 38, when about 61% of the photoreceptors have degenerated, a few GFAP-positive fibers span the retina from the inner limiting membrane to the external limiting membrane. By day 41 and at all later ages examined, Mueller cells radial fibers are labeled throughout the retina. To determine if GFAP expression in Mueller cells is a response to photoreceptor necrosis or a direct mutant gene effect, photoreceptor degeneration was included in normal, adult Sprague-Dawley rats by exposing them to constant light for variable time periods. After 3 days in constant light, there is a 20% reduction in photoreceptor number and many Mueller cells are positive for GFAP. Immunoblot studies confirmed that the anti-GFAP reacted with a single protein from the retina that corresponded in MW and Triton-insolubility to GFAP. The immunoblots also corroborated the results from control and experimental retina anti-GFAP immunostaining. Mueller cells express GFAP immunoreactivity in response to experimentally as well as genetically induced photoreceptor degeneration.