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Figure 4. Ameloblast-lineage cells exposed to fluoride. (A–C) Flow cytometry of ameloblast-lineage passage 2 cells isolated from 21-week-old fetal tissue exposed to: (A) 0 µM F, (B) 10 µM F, or (C) 20 µM F. PI, propidium iodide; Hoechst, Hoechst 33342. The cell group labeled R4 refers to an early-apoptotic population (PI- and increased Ho342 fluorescence), R5 is the late-apoptotic population (intermediate intensity of PI and decreased Ho342 fluorescence), and R2 is the viable cell population. (D) The apoptotic index shows that cells exposed to fluoride had significantly increased apoptosis. The average (SD) apoptotic index of each group: (21W) control, 6.87 (1.44); 10 µm NaF, 11.39 (2.70); 20 µm NaF, 13.84 (1.22); (22W) control, 4.98 (0.73); 10 µm NaF, 9.92 (0.99); 20 µm NaF, 11.43 (1.40) (n = 3). (E) TUNEL staining showed positive clusters of apoptotic cells in green. Scale bar = 20 µm.
