Otpornost ovaca na ovčiju svrabež i postupak uzorkovanja materijala za dijagnostiku patološkog prion proteina kod ovaca

Abstract

Ovčija svrabež (Scrapie, engl.) je neurodegenerativno oboljenje ovaca iz grupe transmisivnih spongiformnih encefalopatija (TSE). Oboljenja iz grupe TSE se nazivaju prionske bolesti, jer je patološki prion protein etiološki faktor za razvoj ovih oboljenja. Ovčija svrabež se javlja u dve forme, kao klasična i atipična. Osetljivost ovaca na ovčiju svrabež zavisi od polimorfizma gena prionskog proteina i prirode uzročnika prionske bolesti. Kodoni 136, 154 i 171 gena prion proteina određuju stepen otpornosti, tj. sklonosti za Scrapie. Pošto je svaki alel obeležen troslovnim kodom, utvrđeno je da su jedinke sa ARR alelom visoko rezistentne na klasičnu ovčiju svrabež, ali ne pruža nikakvu posebnu zaštitu protiv atipične forme Scrapie-a. Primenom qPCR metode može se sprovesti genotipizacija jedinki u cilju uspešne selekcije rezistentnih jedinki na ovčiju svrabež. Za metodu je neophodno uzeti odgovarajući materijal i pripremiti ga za određivanje alela. Određivanje alela qPCR tehnikom sa Taquman probom je moguće iz krvi sa ili bez dodatka antikoagulansa. Za dijagnostiku prisustva patološkog prion proteina kod ovaca u Laboratoriji za patologiju primenjuje se ELISA metoda. Neophodno tkivo za dijagnostiku patološkog prion proteina je obeks produžene moždine. Produžena moždina ovaca se uzorkuje kroz foramen magnum specijalizovanim kašikama za uzorkovanja tkiva malih preživara

Scrapie is a neurodegenerative disease belonging to the group of transmissible spongiform encephalopathies (TSE). Diseases from the TSE group are also known as prion diseases because they are caused by the pathological prion protein. Scrapie is a disease that has two forms, classical and atypical. The susceptibility of sheep to Scrapie depends on the polymorphism of the prion protein gene and the nature of the agent causing prion disease. Codons 136, 154 and 171 of the prion protein gene determine a certain degree of resistance, ie the tendency for Scrapie. Since each allele is marked with a three-letter code, individuals with the ARR allele were found to be highly resistant to classical Scrapie, but did not provide any special protection against the atypical form. Using the qPCR method, genotyping of individuals can be performed for the successful selection of Scrapie resistant animals. It is necessary to sample the appropriate material for qPCR method and to prepare it for the determination of alleles. Determination of alleles by qPCR technique with Taquman test is possible from blood with or without anticoagulants. In the Laboratory of Pathology, the ELISA method is used to diagnose the presence of pathological prion protein in sheep. The Material necessary for the diagnosis of pathological prion protein is the region of obex of medulla oblongata. The medulla oblongata of sheep is sampled through the foramen magnum with specialized spoons for sampling the tissues of small ruminants.