scholarly journals THE ROLE OF THE PIGMENT EPITHELIUM IN THE ETIOLOGY OF INHERITED RETINAL DYSTROPHY IN THE RAT

1971 ◽  
Vol 49 (3) ◽  
pp. 664-682 ◽  
Author(s):  
Dean Bok ◽  
Michael O. Hall
Keyword(s):  
Cell Death ◽  
Outer Segment ◽  
Pigment Epithelium ◽  
Retinal Dystrophy ◽  
Visual Cell ◽  
Sprague Dawley ◽  
Inherited Retinal Dystrophy ◽  
Rcs Rats ◽  
Electron Microscopes ◽  
And Control

Visual cell outer segment renewal was studied in eyes of mutant Royal College of Surgeons (RCS) and Sprague-Dawley (control) rats by a combination of microscopy and radioautography with the light and electron microscopes. RCS and control rats were injected with amino acids-3H at 11 days of age. Radioactive rod outer segment discs were assembled at the outer segment base from radioactive proteins synthesized in the rod inner segments. In controls, all radioactive discs assembled at 11 days of age were displaced the length of the outer segments, removed from outer segment tips, and phagocytized by the pigment epithelium by 8 days after injection. In the RCS rats, disc assembly and displacement resembled controls for the first 3 days after injection. However, as disc assembly continued for some time thereafter, a layer of labeled, disorganized, lamellar debris accumulated between the outer segment tips and the pigment epithelium. The buildup of debris was accompanied by visual cell death. At no time during the study was there evidence for phagocytic activity by the pigment epithelium. 61 days after injection, the layer of debris was the only heavily radioactive component in the retina. In the retina of RCS rats, the outer segment renewal mechanism malfunctions because the pigment epithelium does not fulfill its normal phagocytic role. The end result is visual cell death and blindness.

Inherited retinal dystrophy in RCS rats: a deficiency in vitamin A esterification in pigment epithelium

Nature ◽  
1981 ◽  
Vol 293 (5829) ◽  
pp. 217-220 ◽  
Author(s):  
E. R. Berman ◽  
N. Segal ◽  
S. Photiou ◽  
H. Rothman ◽  
L. Feeney-Burns
Keyword(s):  
Vitamin A ◽  
Pigment Epithelium ◽  
Retinal Dystrophy ◽  
Inherited Retinal Dystrophy ◽  
Rcs Rats

scholarly journals RENEWAL OF FATTY ACIDS IN THE MEMBRANES OF VISUAL CELL OUTER SEGMENTS

1974 ◽  
Vol 61 (2) ◽  
pp. 327-343 ◽  
Author(s):  
Carol Bibb ◽  
Richard W. Young
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Vitamin A ◽  
Palmitic Acid ◽  
Outer Segment ◽  
Pigment Epithelium ◽  
Radioactive Material ◽  
Visual Cell ◽  
Outer Segments ◽  
Acid Exchange

The renewal of fatty acids in the visual cells and pigment epithelium of the frog retina was studied by autoradiographic analysis of animals injected with tritiated palmitic, stearic, or arachidonic acids. Most of the radioactive material could be extracted from the retina with chloroform-methanol, indicating that the fatty acids had been esterified in lipids. Analysis of the extracts, after injection of [3H]palmitic acid, revealed that the radioactivity was predominantly in phospholipid. Palmitic acid was initially concentrated in the pigment epithelium, particularly in oil droplets which are storage sites for vitamin A esterified with fatty acid. The cytoplasm, but not the nucleus of these cells, was also heavily labeled. Radioactive fatty acid was bound immediately to the visual cell outer segment membranes, including detached rod membranes which had been phagocytized by the pigment epithelium. This is believed to be due to fatty acid exchange in phospholipid molecules already situated in the membranes. Gradually, the concentration of radioactive material in the visual cell outer segment membranes increased, apparently as a result of the addition of new phospholipid molecules, possibly augmented by the transfer from the pigment epithelium of esterified vitamin A. Injected fatty acid became particularly concentrated in new membranes which are continually assembled at the base of rod outer segments. This localized concentration was short-lived, apparently due to the rapid renewal of fatty acid. The results support the conclusion that rods renew the lipids of their outer segments by membrane replacement, whereas both rods and cones renew the membrane lipids by molecular replacement, including fatty acid exchange and replacement of phospholipid molecules in existing membranes.

scholarly journals Inherited Retinal Dystrophy in the Mouse: its Appearance in Eyes and Retinae Cultured in vitro

Development ◽  
1958 ◽  
Vol 6 (4) ◽  
pp. 589-592
Author(s):  
D. R. Lucas
Keyword(s):  
Cell Layer ◽  
Retinal Dystrophy ◽  
Visual Cell ◽  
Complete Disappearance ◽  
Cba Mice ◽  
Inherited Retinal Dystrophy

Certain strains of mice, such as C3H, exhibit a recessively inherited retinal dystrophy. This takes the form of a degeneration and complete disappearance of the visual cell layer; it begins on or about the 1 lth day of life and is nearly complete by the 19th day (Sorsby, Roller, Attfield, Davey, & Lucas, 1954). The process is remarkably uniform from litter to litter (Lucas & Newhouse, 1957). In a previous paper (Lucas & Trowell, 1958) it was shown that eyes and retinae taken from 10-day-old normal (CBA) mice could be maintained in vitro for 8 days, during which time their structure was fairly well preserved and differentiation proceeded. In the present work, eyes and retinae from dystrophic strains of mice have been cultured over a similar period to see if the dystrophy developed in vitro. The eyes or retinae of 25 animals from 3 litters of the C3H strain, maintained at the M.R.C.

Congenic strains of RCS rats with inherited retinal dystrophy

1975 ◽  
Vol 66 (4) ◽  
pp. 242-244 ◽  
Author(s):  
M. M. LA VAIL ◽  
R. L. SIDMAN ◽  
C. O. GERHARDT
Keyword(s):  
Retinal Dystrophy ◽  
Congenic Strains ◽  
Inherited Retinal Dystrophy ◽  
Rcs Rats

scholarly journals An extracellular retinol-binding glycoprotein in the eyes of mutant rats with retinal dystrophy: development, localization, and biosynthesis.

1984 ◽  
Vol 99 (6) ◽  
pp. 2092-2098 ◽  
Author(s):  
F Gonzalez-Fernandez ◽  
R A Landers ◽  
P A Glazebrook ◽  
S L Fong ◽  
G I Liou ◽  
...  
Keyword(s):  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Retinal Dystrophy ◽  
Photoreceptor Cells ◽  
Retinol Binding Protein ◽  
Rcs Rat ◽  
Rapid Fall ◽  
Rcs Rats ◽  
Extracellular Transport ◽  
Interphotoreceptor Matrix

Interstitial retinol-binding protein (IRBP) is a soluble glycoprotein in the interphotoreceptor matrix of bovine, human, monkey, and rat eyes. It may transport retinol between the retinal pigment epithelium and the neural retina. In light-reared Royal College of Surgeons (RCS) and RCS retinal dystrophy gene (rdy)+ rats, the amount of IRBP in the interphotoreceptor matrix increased in corresponding proportion to the amount of total rhodopsin through postnatal day 22 (P22). In the RCS-rdy+ rats, the amount increased slightly after P23. However, in the RCS rats there was a rapid fall in the quantity of IRBP as the photoreceptors degenerated between P23 and P29. No IRBP was detected by immunocytochemistry in rats at P28. The amount of rhodopsin fell more slowly. Although retinas from young RCS and RCS-rdy+ rats were able to synthesize and secrete IRBP, this ability was lost in retinas from older RCS rats (P51, P88) but not their congenic controls. The photoreceptor cells have degenerated at these ages in the RCS animals, and may therefore be the retinal cells responsible for IRBP synthesis. The putative function of IRBP in the extracellular transport of retinoids during the visual cycle is consistent with a defect in retinol transport in the RCS rat reported by others.

scholarly journals Chronically shortened rod outer segments accompany photoreceptor cell death in Choroideremia

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242284
Author(s):  
Ingrid P. Meschede ◽  
Thomas Burgoyne ◽  
Tanya Tolmachova ◽  
Miguel C. Seabra ◽  
Clare E. Futter
Keyword(s):  
Cell Death ◽  
Membrane Trafficking ◽  
Outer Segment ◽  
Photoreceptor Cell ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Membrane Traffic ◽  
Rod Outer Segments ◽  
Rab Protein ◽  
Outer Segments

X-linked choroideremia (CHM) is a disease characterized by gradual retinal degeneration caused by loss of the Rab Escort Protein, REP1. Despite partial compensation by REP2 the disease is characterized by prenylation defects in multiple members of the Rab protein family that are master regulators of membrane traffic. Remarkably, the eye is the only organ affected in CHM patients, possibly because of the huge membrane traffic burden of the post mitotic photoreceptors, which synthesise outer segments, and the adjacent retinal pigment epithelium that degrades the spent portions each day. In this study, we aimed to identify defects in membrane traffic that might lead to photoreceptor cell death in CHM. In a heterozygous null female mouse model of CHM (Chmnull/WT), degeneration of the photoreceptor layer was clearly evident from increased numbers of TUNEL positive cells compared to age matched controls, small numbers of cells exhibiting signs of mitochondrial stress and greatly increased microglial infiltration. However, most rod photoreceptors exhibited remarkably normal morphology with well-formed outer segments and no discernible accumulation of transport vesicles in the inner segment. The major evidence of membrane trafficking defects was a shortening of rod outer segments that was evident at 2 months of age but remained constant over the period during which the cells die. A decrease in rhodopsin density found in the outer segment may underlie the outer segment shortening but does not lead to rhodopsin accumulation in the inner segment. Our data argue against defects in rhodopsin transport or outer segment renewal as triggers of cell death in CHM.

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