Figure 2.

NAC effects on the cellular Cu and Zn content of HepG2, HT-29, and THP-1 cells. Cells were cultured 6 h with or without 1 mM NAC in combination with 50 µM CuSO₄, 50 µM ZnSO₄ or both. The (a,c,e) Cu and (b,d,f) Zn content was measured using total reflection X-ray fluorescence (TXRF) spectroscopy in HepG2 (a,b), HT-29 (c,d), and THP-1 (e,f) cells. Results are depicted as mean +SD (n = 3–4). Statistical analysis was calculated by two-way ANOVA with Bonferroni´s post-test. ** p < 0.01; *** p < 0.001 vs. cells without Zn and Cu treatment (trace element effect); ^# p < 0.05; ^## p < 0.01; ^### p < 0.001 vs. −NAC (NAC effect); ^§§§ p < 0.001 as indicated. n.d. = not detectable.