Development and degeneration of retina in rds mutant mice: altered disc shedding pattern in the albino heterozygotes and its relation to light exposure.
The number of phagosomes in the retinal pigment epithelium (RPE) of normal albino mice, maintained in cyclic light, is highest at the time of onset of light. The number declines to the lowest level around the start of the dark period. If the dark period is prolonged, the pattern of shedding remains cyclic but the phagosome count is higher than normal. If the light period is prolonged the phagosome count remains low and the rise to the peak is delayed. The number of phagosomes in the RPE of albino rds/+ mice, maintained in cyclic light, peaks to higher than normal level and the peak is recorded near the end of the light period. If the dark period is prolonged the phagosome count in the RPE of rds/+ mice remains lower than in the similarly treated normal mice. The phagosome count in the RPE of rds/+ mice, exposed to a prolonged light period, remains higher than in the similarly treated normal mice. In both normal and rds/+ mice, born and reared in total darkness, the pattern of disc shedding is very different but the rds/+ mice show a relatively higher frequency of phagosomes in the RPE than the normal mice. The phagosomes in the rds/+ RPE are larger than normal. An increase in size appears to correspond with increased rate of shedding in the rds/+ mice and to a lesser extent also in normal mice. Thus, the pattern of disc shedding in the albino rds/+ mice, which is different from the normal albino mice, also shows a different reaction to changes in the environmental light.
Sanyal
S
S
Department of Anatomy, Faculty of Medicine, Erasmus University, Rotterdam, The Netherlands.
Hawkins
R K
RK
D000818:Animals; D002452:Cell Count; D003624:Darkness; D008027:Light; D051379:Mice; D008807:Mice, Inbred BALB C; D008817:Mice, Mutant Strains; D010588:Phagosomes / Q000473:pathology; D010857:Pigment Epithelium of Eye / Q000473:pathology*; D012162:Retinal Degeneration / Q000473:pathology*; D012374:Rod Cell Outer Segment / Q000473:pathology; D013997:Time Factors