Slowly progressive changes of the retina and retinal pigment epithelium in briard dogs with hereditary retinal dystrophy
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Seven eyes from 2 generations of Briard dogs (5 weeks — 7 years old) with congenital night blindness and (in the second generation) impairment of day vision to varying degrees, were examined by light and electron microscopy. Specimens from 4 locations were studied: the central area, the midperiphery of the tapetal area, the upper periphery and the lower periphery. Disorientation of rod outer segment disc membranes was seen in the 5-week-old dog. Large electron-lucent inclusions were found in the RPE at 3.5 months of age. These inclusions occurred most frequently in the central and midperipheral-tapetal areas and seemed to increase in numbers and spread towards the periphery with increasing age. The content of these inclusions is not elucidated. Rod photoreceptor degeneration was apparent from 7 months of age and was most prominent in the peripheral areas. The cones were better preserved. The 7-year-old dog showed reduction of photoreceptors in the central and midperipheral-tapetal areas and almost complete photoreceptor degeneration in the periphery. This dog also showed severe changes of the inner retina in the peripheral fundus. It appears that these Briard dogs suffer from a very slowly progressive retinal degeneration, in which the photoreceptor degenerative changes do not correlate anatomically to the changes in the RPE cells. The disease seems to be different from the retinopathy described in the English Briards. It is not clear yet whether the lipid type of retinopathy found in American Briards is identical to the present disease.
Key wordsAnimal model Briard dogs Electron microscopy Photoreceptors Retinal degeneration Retinal pigment epithelium
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- 1.Aguirre G. Inherited retinal degenerations in the dog. Trans Am Acad Ophthalmol Otol 1976; 81: 667–76.Google Scholar
- 11.Parshall CJ, Wyman M, Nitroy S, Acland G, Aguirre G. Photoreceptor Dysplasia: An Inherited Progressive Retinal Atrophy of Miniature Schnauzer Dogs. Prog Vet Comp Ophthalmol 1991; 1: 187–203.Google Scholar
- 14.Aguirre G, Acland G. Inherited retinal degeneration in the Labrador retriever dog. A new animal model of RP? Invest Ophthalmol Vis Sci 1991; 32 (ARVO suppl):889.Google Scholar
- 18.Rubin LF. Briard. In: Inherited Eye Diseases in Purebred Dogs. Baltimore: Williams & Wilkins 1989; 56–8.Google Scholar
- 19.Bedford PCG. Retinal pigment epithelial dystrophy (CPRA): A study of the disease in the Briard. J Small Anim Pract 1984; 25: 129–38.Google Scholar
- 20.Riis RC, Aguirre GD. The Briard Problem. Proc Am Coll Vet Ophth 1983; 62–75.Google Scholar
- 22.Narfström K, Wrigstad A, Ekesten B, Nilsson SEG. Hereditary Retinal Dystrophy in the Briard Dog: Clinical and Hereditary Characteristics. Prog Vet Comp Ophthalmol 1994; 4: 85–92.Google Scholar
- 25.Riis RC, Siakotos AB. Inherited lipid retinopathy within a dog breed. Invest Ophthalmol Vis Sci 1989; 31 (ARVO suppl): 308.Google Scholar