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Ultrastructural and ERG findings in progressive rod‐cone dystrophy in a litter of Labrador Retrievers
Author(s) -
Raitta Christina,
Kommonen Bertel,
Ulshafer Robert,
Karhunen Ulla
Publication year - 1991
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.1991.tb01985.x
Subject(s) - erg , outer nuclear layer , dystrophy , photopic vision , retinitis pigmentosa , ultrastructure , electroretinography , retina , anatomy , biology , retinal , retinal pigment epithelium , ophthalmology , pathology , medicine , neuroscience
Early ultrastructural findings of a progressive photoreceptor dystrophy and corresponding ERG findings are reported in 3 Labrador Retrievers from a litter of 7 pups bred from 2 dogs clinically and electroretinographically affected with generalized progressive retinal dystrophy. The pups were euthanized at 5, 11 and 15 months post partum. The most prominent ultrastructural finding was photoreceptor dystrophy. At 5 months the outer nuclear layer (ONL) consisted of 8–10 layers and seemed reduced in thickness, pyknotic nuclei were seen in this layer. The receptor outer segments (OS) were short and swollen. Some disorientation of OS discs occurred. In the 11‐months specimen 7–8 ONL layers were identified. Overall thinning of the neuro‐retina had occurred and fewer receptors compared to the 5‐months specimen were present. By 15 months the ONL was further reduced to about 4 layers. Enlarged internuclear spaces were present in the ONL as well as around inner segments (IS). Phagocytic cells were frequent among remains of OS. The pigment epithelium appeared normal. The dark adapted ERG b‐wave amplitudes and photopic 30 Hz flicker responses were low in comparison to controls of the same breed, and decreased with age. The condition represents a progressive rod‐cone dystrophy which shares similarities with primary receptor dystrophy in man such as retinitis pigmentosa.