TITLE

Clinical, electroretinographic and histomorphometric evaluation of the retina in sheep with natural scrapie

AUTHOR(S)
Regnier, Alain; Andreoletti, Olivier; Albaric, Olivier; Gruson, Delphine Cayez; Schelcher, François; Toutain, Pierre-Louis
PUB. DATE
January 2011
SOURCE
BMC Veterinary Research;2011, Vol. 7 Issue 1, p25
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Background: The retina is part of the diencephalon in a peripheral location and may be involved in prion diseases. Retinal function and structural changes were assessed in naturally scrapie-affected red face Manech ewes presenting the classical signs of the disease, and clinically healthy age-matched subjects for controls. Ophthalmic examination was done prior to electroretinography (ERG), which was carried out under conditions that allowed photopic and scotopic activities to be assessed. Histomorphometry of the inner and outer retinal layers was performed post-mortem, and retinas were also examined for evidence of abnormal prion protein (PrPSc) accumulation and glial fibrillary acidic protein (GFAP) upregulation as a marker of gliosis. Scrapie status was determined by examination of brain tissue Results: Ocular reflexes and ophthalmoscopy did not reveal any difference between scrapie affected and control animals. Although the light-and dark-adapted ERG responses of both rod-and cone-mediated functions had a similar waveform in scrapie-affected and control sheep, a significant reduction in the amplitude of the ERG a-and b-waves was observed in affected animals compared to controls. These functional alterations were correlated with a substantial loss of cells in the outer nuclear layer (ONL), lengthening and disorganization in photoreceptor segments, and substantial reduction in cellularity and thickness of the inner nuclear layer (INL). The degenerative changes in the INL and ONL were most marked in the central and paracentral areas of the scrapie retinas, and were accompanied in all scrapie retinas by PrPScdeposition in the ganglion cell and synaptic layers. GFAP immunoreactivity was mainly increased in the ganglion cell and inner plexiform layers. Conclusions: No appreciable fundoscopic changes were observed in the scrapie-affected ewes although reproducible changes in retinal function as measured by ERG were observed in these animals. The alterations in the receptoral and post-receptoral pathways corresponded to the degenerative lesions observed in the ONL and INL of the scrapie retinas. The retinal degeneration was associated with prion protein infectivity which presumably spread via the optic nerve.
ACCESSION #
62822494

 

Related Articles

  • Estimation of the relative risk of developing clinical scrapie: the role of prion protein (PrP) genotype and selection bias. Tongue, S. C.; Pfeiffer, D. U.; Warner, R.; Elliott, H.; Del Rio Vilas, V. // Veterinary Record: Journal of the British Veterinary Association;1/14/2006, Vol. 158 Issue 2, p43 

    Prion protein (PrP) genotype data from statutory confirmed cases and from three non-case datasets have been used to calculate the odds ratio (OR) for the development of clinical scrapie for an individual sheep of a given PrP genotype, compared with one possessing the ‘wild-type’...

  • ARS and Partners Set Their Sights on Scrapie in Goats. Suszkiw, Jan // Agricultural Research;Apr2009, Vol. 57 Issue 4, p12 

    The article describes the efforts of scientists of the United States Agricultural Research Service to help goats combat scrapie, a transmissible spongiform encephalopathy. Infected goats cannot be cured and will eventually die from the affliction. Scientists have developed the rectal...

  • Genetic Structure at PRN-P Locus and Framing Risk Classes for Scrapie Resistance in Merinos of Cluj Breed. CONSTANTINESCU, Radu; COŞIER, Viorica; MIREŞAN, Vioara; VLAIC, Auigustin; COCAN, Daniel; RĂDUCU, Camelia; FEŞTILĂ, Iulia // Bulletin of the University of Agricultural Sciences & Veterinary;2012, Vol. 69 Issue 1/2, p303 

    The present paper shares the results of genetic structure analysis of the PEN-P gene, carried out in an ovine nucleus of Merinos of Cluj breed. Biological samples (blood) were collected from 20 rams (Merinos of Cluj breed) from a herd in genetics conservation belonging to SDE Cluj-Napoca and...

  • Clinical characterisation of natural scrapie in a native Spanish breed of sheep. Vargas, F.; Bolea, R.; Monleón, E.; Acín, C.; Vargas, A.; De Blas, I.; Luján, L.; Badiola, J. J. // Veterinary Record: Journal of the British Veterinary Association;3/5/2005, Vol. 156 Issue 10, p318 

    Describes a study to characterize the clinical features observed in sheep naturally affected with scrapie in Aragon, Spain, and to compare the results with previously described findings. Alternation of mental status; Excitatory signs such as restlessness, anxiety and a tendency to avoid...

  • scrapie disease:. Huber, Jeffrey T.; Gillaspy, Mary L. // Encyclopedic Dictionary of AIDS-Related Terminology;2000, p196 

    An encyclopedia entry for scrapie disease is presented. Scrapie is one of the transmissible brain diseases in which the brain degenerates to the appearance of a sponge. The condition is characterized by severe itching, debility, and the inability to coordinate muscle movements. It generally...

  • In vitro amplification of ovine prions from scrapie-infected sheep from Great Britain reveals distinct patterns of propagation. Thorne, Leigh; Holder, Thomas; Ramsay, Leigh; Edwards, Jane; Taema, Maged Mohamed; Windl, Otto; Maddison, Ben Charles; Gough, Kevin Christopher; Terry, Linda Ann // BMC Veterinary Research;2012, Vol. 8 Issue 1, p223 

    Background: Protein misfolding cyclic amplification (PMCA) is a method that facilitates the detection of prions from many sources of transmissible spongiform encephalopathy (TSE). Sheep scrapie represents a unique diversity of prion disease agents in a range of susceptible PRNP genotypes. In...

  • Results of a postal survey of scrapie in the Shetland Islands in 2003. Gubbins, S.; Clark, A. M.; Eglin, R. D.; Sivam, S. K. // Veterinary Record: Journal of the British Veterinary Association;2/25/2006, Vol. 158 Issue 8, p255 

    In February 2003, a postal survey of 1279 sheep farmers in the Shetland Islands yielded 586 responses (46 per cent response rate). The principal aim of the survey was to gather information on the history and control of scrapie. Overall, 28.5 per cent of the respondents thought they had had a...

  • ST1859 reduces prion infectivity and increase survival in experimental scrapie. Colombo, Laura; Piovesan, Paola; Ghirardi, Orlando; Salmona, Mario; Forloni, Gianluigi // Archives of Virology;Sep2009, Vol. 154 Issue 9, p1539 

    On the basis of the structural homologies between ST1859 (1[(2-hydroxy-1-naphtyl)methyl]-2-naphthol) and the anti-prion agents and its anti-amyloidogenic activity, we tested whether this molecule altered the biochemical properties of aggregates formed in vitro by synthetic prion peptides and...

  • Sparse PrPSc accumulation in the placentas of goats with naturally acquired scrapie. O'Rourke, Katherine I.; Dongyue Zhuang; Truscott, Thomas C.; Huijan Yan; Schneider, David A. // BMC Veterinary Research;2011, Vol. 7 Issue 1, p7 

    Background: Domestic goats (Capra hircus) are a natural and experimental host of scrapie and bovine spongiform encephalopathy, the transmissible spongiform encephalopathies (TSE) of sheep and cattle. Goats are also susceptible to experimental infection with the agents of TSEs of deer and elk...

Share

Read the Article

Courtesy of VIRGINIA BEACH PUBLIC LIBRARY AND SYSTEM

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics