Gene expression, oxidative stress and apoptotic changes in rabbit ileum experimentally infected with Eimeria intestinalis

Abstract

Coccidiosis is a parasitic disease caused by protists (apicomplexans) of the genus Eimeria Schneider, 1875 and is consideredto be the most important disease faced by rabbit breeders due to its high morbidity. In the present study, the antioxidant status andchanges in apoptosis and in the expression of some genes were quantified in rabbits' ilea following infection with Eimeria intestinalisCheissin, 1948. Rabbits, orally infected with 1 × 105 sporulated oocysts of E. intestinalis, started to shed oocysts in their faeces on8 days post infection (dpi) and reached maximum excretion on 10 dpi, with approximately 5 million oocysts. This was accompanied bya significant decrease in the live body weight of infected rabbits. Also, malondialdehyde and nitric oxide were significantly increasedwhile catalase and glutathione were significantly decreased in the ileum tissues of the infected rabbits. In addition, a significant increasewas observed in the percentages of apoptotic cells in the ilea of the infected rabbits. Furthermore, interleukin-1β and interleukin-2mRNA levels were significantly down-regulated and mRNA levels of interleukin-6, interferon gamma and inducible nitric oxidesynthase were significantly up-regulated, while those of C-reactive protein remained unchanged. We conclude that infection withE. intestinalis induces oxidative stress, a significant increase in the percentage of apoptotic cells and a diverse and robust Th1 andTh1-related cytokine response in the ileum tissues.