Determination of extracellular traps structures from sheep polymorphonuclear leukocytes to Echinococcus granulosus protoscoleces

Abstract

It was aimed to detect extracellular traps structures from sheep polymorphonuclear leukocytes (PMN) after being confronted with Echinococcus granulosus protoscoleces in vitro. Also, the effect of cyst fluid was examined on the development of extracellular traps. At the end of the incubation for 1 h, the extracellular traps augmented with neutrophil elastase, histone (H3) and myeloperoxidase were visualized in the protoscoleces-PMN co-culture microscopically. Some protoscoleces lysed and the chitinous hooks released were surrounded by the extracellular traps. The other protoscoleces were still intact and the extracellular trap structures were observed around them. The relationship between the extracellular DNA contents and the protoscoleces concentration was not found statistically significant (P > 0.05). The extracellular DNA amount in the co-cultures diluted in RPMI-1640 increased with the incubation time (P < 0.05). However, the time-dependent relationship was not found in the co-cultures diluted in the cyst fluid (P > 0.05). The difference in the extracellular DNA amount was detected as statistically significant (P < 0.05) between the two co-culture groups (diluted in RPMI-1640 or the cyst fluid), except for 30 min incubation. To the Author's knowledge, NETosis reaction was firstly observed in sheep PMN after being confronted with protoscoleces in vitro. The cyst fluid had some negative effects on the development of extracellular traps from sheep PMNs at the 1-h incubation time. It should be investigated which molecules are responsible for NETosis inhibition in hydatid cyst fluid. Future studies may clarify whether neutrophils fight with protoscoleces by using their different mechanisms.