Maia-Brigagão C, Morgado-Díaz J A, De Souza W
Laboratório de Ultraestrutura Celular Hertha Meyer, Universidade Federal do Rio de Janeiro, Brazil.
Parasitol Int. 2012 Jun;61(2):280-7. doi: 10.1016/j.parint.2011.11.002. Epub 2011 Nov 26.
Giardia duodenalis is a parasitic protozoan that causes diarrhea and other symptoms which together constitute a disease known as giardiasis. Although the disease has been well defined, the mechanisms involving the establishment of the infection have not yet been fully elucidated. In this study, we show that after 24h of interaction between parasites and intestinal Caco-2 cells, there was an alteration of the paracellular permeability, as observed by an approximate 42% of reduction in the transepithelial electrical resistance and permeation to ruthenium red, which was concomitant with ultrastructural changes. Nevertheless, epithelium viability was not affected. We also demonstrate that there was no change in expression of junctional proteins (tight and adherens) but that the distribution of these proteins in Caco-2 cells after parasite adhesion was significantly altered, as observed via laser scanning confocal microscopy 3D reconstruction. The present work shows that adhesion of Giardia duodenalis trophozoites to intestinal cells in vitro induces disturbances of the tight, adherens and desmosomal junctions.
十二指肠贾第虫是一种寄生原生动物，可引起腹泻及其他症状，这些症状共同构成一种名为贾第虫病的疾病。尽管该疾病已得到明确界定，但感染确立所涉及的机制尚未完全阐明。在本研究中，我们发现寄生虫与肠道Caco-2细胞相互作用24小时后，细胞旁通透性发生改变，表现为跨上皮电阻降低约42%以及对钌红的通透性增加，这与超微结构变化同时出现。然而，上皮细胞活力未受影响。我们还证明，连接蛋白（紧密连接和黏附连接）的表达没有变化，但通过激光扫描共聚焦显微镜三维重建观察到，寄生虫黏附后这些蛋白在Caco-2细胞中的分布发生了显著改变。目前的研究表明，十二指肠贾第虫滋养体在体外黏附肠道细胞会导致紧密连接、黏附连接和桥粒连接受到干扰。
