Fig. 2
TiO2-NP treatment impaired the physiology barrier function of endothelial cells. a TEM images showed TJ ultrastructure in the border of adjacent bEnd.3 cells (black arrow). After 12 h incubation with 500 ng/mL TiO2-NPs, the appearance of TJ was dramatically reduced, and an enlarged cleft between adjacent cells were observed (indicated by white ellipse). The N and m represents the nucleus and the mitochondria, respectively. Asterisk indicates the engulfed TiO2-NPs. b Paracellular tracer-flux assays were performed using postconfluent monolayers of bEnd.3 cell and RPEC, as described in Materials and Methods. Treatment with TiO2-NPs (500 ng/mL, 12 h) caused an increase in the paracellular permeability of FITC-dextrans (M.W. 40 and 70 kDa); results from 3 to 4 independent experiments are shown. *p < 0.05: significant differences relative to control. c/d After a treatment of TiO2-NPs, TEER was measured (3, 6, 12, 24 h after treatment) between the apical and the basolateral compartment, employing an EVOM ohmmeter. Normalized TEER value (% related to control) was notably reduced after TiO2-NP treatment, either in time-dependent manner c or in mass-dependent manner d. (N > 4) *p < 0.05, **p < 0.01, ***p < 0.001, indicates statistically significant difference from the control treatment