Demonstration of peripherin/rds mRNA in normal and light-damaged rat retinas by in situ hybridization histochemistry.

Cellular expression of the mRNA for peripherin/rds was studied in rat retinas by in situ hybridization histochemistry with antisense and sense probes prepared from polymerase chain reaction-amplified cDNA of the bovine peripherin/rds. Predominant mRNA signals were detected in the inner segments and distal region of the outer nuclear layer, but not in other layers of the retina including retinal pigment epithelium or in the choroid, giving evidence that the gene product, peripherin/rds, is synthesized specifically in the inner segment ribosomes to form outer segment disc membranes of photoreceptor cells. The in situ hybridization technique was applied to explore how mRNA for peripherin/rds is affected by light-induced retinal damage in rats. Following 3 days of continuous exposure to low-intensity fluorescent light, the mRNA expression in adult rats was found to be defective, although photoreceptor cells were still observed by light microscopy. After longer exposure to continuous light, the mRNA expression was severely damaged or undetectable, together with loss of photoreceptor cells.