Laboratório de Ultraestrutura Celular, Universidade Santa Úrsula, Rua Jornalista Orlando Dantas, 59, Botafogo, CEP 22231-010, Rio de Janeiro, Brazil.
Protist. 2012 Jul;163(4):529-43. doi: 10.1016/j.protis.2011.11.005. Epub 2012 Feb 5.
The protozoan parasite Tritrichomonas foetus displays a pear-shaped form and a pseudocyst stage. However, little is known about the biology of the pseudocyst. The aim of this work was to assess whether pseudocysts exert cytotoxic effects during their interaction with MDCK cells (an epithelial kidney canine cell line) and compare their behavior to that of the pear-shaped parasites. Pseudocysts and pear-shaped parasites from both cultured and freshly isolated T. foetus were used. Electron microscopy revealed that the epithelial cells exhibited more signs of injury, such as depletion of microvilli, retraction from neighboring cells and swollen mitochondria with loss of electron density in the matrix, when the pseudocysts were used in interaction experiments. In addition, during the co-incubation with MDCK cells, pseudocysts exhibited a more intense amoeboid transformation than that found in pear-shaped parasites. The MTT viability assay demonstrated that the pseudocysts were more cytotoxic when in contact with host cells as compared to the flagellated pear-shaped parasites. The JC-1 viability assay revealed that pseudocysts induced a higher loss of mitochondrial membrane potential compared to pear-shaped parasites. Pseudocysts undergoing a budding process were observed after 2.5h of co-incubation with MDCK cells. Our results suggest that the T. foetus pseudocyst might be a more aggressive form.
纤毛原虫寄生虫 Trichomonas foetus 呈梨形，并具有假囊阶段。然而，关于假囊的生物学特性知之甚少。本研究旨在评估假囊在与 MDCK 细胞（犬肾上皮细胞系）相互作用过程中是否产生细胞毒性作用，并将其行为与梨形寄生虫进行比较。使用了来自培养和新鲜分离的 T. foetus 的假囊和梨形寄生虫。电子显微镜显示，当使用假囊进行相互作用实验时，上皮细胞表现出更多的损伤迹象，例如微绒毛耗竭、与邻近细胞回缩以及线粒体肿胀，基质中的电子密度丧失。此外，在与 MDCK 细胞共孵育期间，与梨形寄生虫相比，假囊表现出更强烈的变形虫样转化。MTT 活力测定表明，与有鞭毛的梨形寄生虫相比，与宿主细胞接触时假囊的细胞毒性更强。JC-1 活力测定显示，与梨形寄生虫相比，假囊诱导的线粒体膜电位丧失更高。在与 MDCK 细胞共孵育 2.5 小时后观察到假囊进行出芽过程。我们的结果表明，T. foetus 假囊可能是一种更具侵袭性的形式。
