A comparative study of distribution of 70 kD stress protein in the retina between the normal and retinal dystrophic rat]

The immunolocalization of 70 kD stress protein (SP70) was investigated in the retinal tissues of normal Sprague-Dawley (SD) rat and that of the Royal College of Surgeons (RCS) rat with inherited retinal dystrophy. From postnatal day 2 to 15, SP70 was present in the maturing retinal tissues of both rat strains. In the RCS rat retina of postnatal day 22, at the onset of retinal degeneration, SP70 was expressed in the retinal pigment epithelium (RPE). At postnatal day 40, immunostaining for SP70 was considerably reduced in the degenerating RCS retina. In the RCS retina at postnatal day 90, immunostaining for SP70 was completely lost except for the ganglion cells and the inner plexiform layers. These results suggested that, at the onset of retinal degeneration, the RCS retina may have a state of metabolic stress, which induced SP70 expression in the RPE. At the end stage of retinal degeneration, the immunostaining for SP70 was lost, suggesting the lack of production of SP70 in the degenerated retinal tissue.