Glutathione peroxidase (GPX) activity in blood of ewes on farms in different scrapie categories in Iceland

• Published in: Acta Veterinaria Scandinavica
• Main Authors: Eiríksson Tryggvi, Sigurdarson Sigurdur, Kristinsson Jakob, Gudmundsdóttir Kristín B, Jóhannesson Torkell
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2008
• Subjects: Veterinary medicine; SF600-1100; Iceland
• Online Access: https://doi.org/10.1186/1751-0147-50-23; https://doaj.org/article/80763ac0242546a7becde21744edae52

Abstract Background Preliminary studies indicated decreased glutathione peroxidase (GPX) activity in blood of ewes on scrapie-afflicted farms. Other studies have shown decreased GPX activity in brain of prion-infected mice and in prion-infected cells in vitro . The aim of this study was to examine the GPX activity in blood as well as the distribution of GPX-activity levels from ewes on farms in scrapie-afflicted areas in Iceland. Methods Blood samples were collected from 635 ewes (non-pregnant [n = 297] and pregnant [n = 338]) on 40 farms in scrapie-afflicted areas during the years 2001–2005, for analysis of GPX activity. The farms were divided into three categories: 1. Scrapie-free farms (n = 14); 2. Scrapie-prone farms (earlier scrapie-afflicted, restocked farms) (n = 12); 3. Scrapie-afflicted farms (n = 14). For comparison, 121 blood samples were also collected from non-pregnant ewes on one farm (farm A) in a scrapie-free area (scrapie never registered). Chi-square test was used to test for normal distribution of GPX-results, and Kruskal-Wallis test to compare GPX-results between categories. Results The GPX-results appeared to be biphasically distributed in ewes in all three scrapie categories and on farm A. The presumptive breaking point was about 300 units g Hb -1 . About 30–50% of the GPX-results from ewes in all three scrapie categories were below 300 units g Hb -1 but only about 13% of the GPX-results from ewes on farm A. The mean GPX activity was highest on farm A, and was significantly lower on scrapie-prone farms than on scrapie-free or scrapie-afflicted farms (non-pregnant and pregnant ewes: P < 0.005, respectively; non-pregnant and pregnant ewes combined: P < 0.0005). Conclusions 1) the distribution of GPX-results in blood of Icelandic ewes apparently has a biphasic character; 2) the GPX-results were higher in ewes on one farm in a scrapie-free area than in ewes on farms in the scrapie-afflicted areas; 3) GPX-activity levels were significantly lowest on earlier scrapie-afflicted, restocked ...