Fig. 6

Palmitic acid does not affect lysosome acidity and integrity but increases the number of lysosomes per cell. The ZF4 cells were incubated for 2.5 h with PA, 3 MA, RAPA or CQ. Untreated controls were also included. For PA and untreated control, the ZF4 cells were also incubated for 24 h. Live cells were stained with LysoSensor Blue DND-167 reagent for acidic lysosomal vesicle detection. Images were taken by confocal microscopy. (A, B) Compared to the respective controls, RAPA- and 3 MA-treated cells showed no significant differences in the number of lysosomes after 2.5 h. CQ and PA induced a significant increase in the number of lysosomes per cell compared to the other treatments. (C, D) The accumulation of lysosomes induced by PA persisted after 24 h and was significantly higher compared to the cells stimulated for 2.5 h. Data are shown as the mean ± SEM of the number of lysosomes per cell counted in 8–10 images per treatment. Comparisons among groups were made using one-way ANOVA (multiple comparisons) followed by a Student-Newman-Keuls test. Significant differences are displayed as *** (0.0001 < p < 0.001), ** (0.001 < p < 0.01) or * (0.01 < p < 0.05). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)