Apoptotic effects of antimalarial artemisinin on the second generation merozoites of Eimeria tenella and parasitized host cells

- Artemisinin reduces the number of merozoites of E. tenella and alleviates cecal lesions.
- Artemisinin facilitates apoptosis in second-generation merozoites of E. tenella.
- Artemisinin inhibits Bcl-2 activity whereas increases caspase-3 activity in Eimeria infected tissues.

Artemisinin (ART) is a sesquiterpene lactone isolated from Artemesia annua L., and well-known for the antimalarial treatment. Recently many reports show the effectiveness of ART in the control of poultry coccidiosis, but the mechanism remains unclear. In this study, we found that ART could effectively improve the pathological alterations in chicken ceca infected by E. tenella with decreased number of second generation merozoites (SGM). In addition, ART significantly reduced mitochondrial membrane potential by 47.4% and notably increased apoptotic rate by 61.9% in SGM. Morphological analysis showed that SGM with ART treatment represented some apoptotic features such as the condensability of chromatin, increase of cytoplasmic density and the marginalization of heterochromatin. We also found that ART treatment significantly increased caspase-3 activity whereas reduced Bcl-2 activity in cecum tissues compared with the infection group by immunohistochemical analysis. These results suggest the anticoccidial effects of ART are closely related to facilitate apoptosis in both merozoites and the infected host cells. This study makes a better understanding of ART against poultry coccidiosis.