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Figure 5 | Particle and Fibre Toxicology

Figure 5

From: Action of polystyrene nanoparticles of different sizes on lysosomal function and integrity

Figure 5

Enlargement of the endosomal-lysosomal system and changes in lysosomal enzyme activities in EAhy926 cells after 24h and 72h of exposure to 20 μg/ml CPS of different sizes in DMEM + 2%FBS. 25 μM chloroquine was used as positive control (pos. co). a: Lysosomal/cytotoxicity assay, where an increase in the green signal is interpreted as perturbation in lysosome function. The signal is normalized to that of un-treated cells as 100%. Significant effects (asterisk) are seen only after incubation for 24h with 20 nm CPS. b: Changes in the reactivity with CV-(RR)2 for cathepsin B (CatB) and with substrate for lysosomal sulfatases (Lyso). Arbitrary fluorescence data are normalized to the amount of LAMP-1 staining and the signal of un-treated cells is set as 100%. In general, decreases in lysosomal activities were more pronounced after 24h of exposure than after 72h of exposure and the effect on lysosomal sulfatases was higher than that on cathepsin B. After 24h of exposure, significant decreases in the activity of lysosomal sulfatase were seen for all particles. After 72h, such significant decreases were only seen upon exposure to 20 nm CPS and 200 nm CPS. Significant changes are marked by asterisks.

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