ABSTRACT
Cadmium (Cd) affects cell proliferation, differentiation, apoptosis and other cellular activities and can cause numerous molecular lesions that would be relevant to carcinogenesis. The mechanism of adverse effects of Cd has been poorly understood and, especially on the tight junction. Since there is rare information about the effect of Cd on tight junction protein, we here investigated whether Cd can alter the localization of the proteins. This study examined Cd effects on of tight junction (occludin, ZO-1, and ZO-2) using MDCK cell culture. The change of MDCK cell and tight junction was investigated after treatment of cadmium with phase contrast microscopy, TEER, cell viability, Transmission electron microscopy and confocal laser microscopy. After treatment of cadmium, transendothelial electrical resistance decreased with time and concentration dependent manner. AlamarBlue assay revealed that decreased cell viability also decreased with time and concentration dependent manner. The tight junction moved down between intercellular spaces with decreased density and the cellular thickness around cell junctions decreased with increasing concentration and exposure time of CdCl2. The MDCK cells eventually showed cell death with. Confocal laser microscopy revealed that immunofluorescent reaction of occludin, ZO-1 and ZO-2 decreased. Occludin, ZO-1 and ZO-2 were disrupted at tight junction. These data suggest that after treatment of Cd, increased permeability of MDCK cell monolayer increased. This might be accompanied with disruption of occludin, ZO-1 and ZO-2.