Heterogeneity of PrP in Brains of Hamsters Infected with Scrapie 263 K Strain and the Dynamic Detection by Western blot
Metabolic and conformatio nal alterations of the cellular pr ion protein(PrP~C)are the essential causes of transmissible spongiform encephalopathies in human and anim als.A hamster-adapted scrapie agen t 263K was intracerebrally inocula ted into Syrian hamsters and the differen t forms of the abnormal prion pro tein(PrP~(Sc))were dynamically detect ed on the 20~(th),40~(th),50~(th),60~(th ),70~(th),and 80~(th) day post-inoculati on by Western blot.PrP~(Sc) was firstly det ected in the brain tissues of the animals 40 days post-inoculation,t hat was much earlier than the onse t of the disease (the mean incubat ion period is 66.7±1.1 days).Besid es the PrP with standard molecular weight (30-35kD),various high mole cular masses of PrP as well as the low were repeatedly identified fro m the infected brains.The amounts of these heterogeneous PrP increas ed along with the prolongation of incubation,while the appearance of the low molecular mass of PrP in b rain tissues was most probably dis ease-specific.Deglycosylation assa ys identified another PrP fragment with much lower molecular weight i n the infected brains in addition to the PrP with standard molecular weight,whereas only the latter cou ld be found in the healthy animals .The truncated PrP in the infected brains may have the similar glycos ylation patterns as the full-lengt h PrP.Moreover,the percentage of n on-glycosylated PrP increased dram atically at the terminus of the il lness.These results suggest that variou s molecular patterns of PrP~(Sc) may indwell in brain tissues during th e infection.The metabolism of PrP in the infected hamsters may diffe r from the healthy ones.