Effect of FFAs and TNF-α on the mitochondrial potential. HepG2 cells were exposed to different types of FFA and/or TNF-α for 24 h. After the treatments, the cells were exposed to 5 μM JC-1 dye in DMEM for 30 minutes, and then washed with PBS. Fluorescence of the cells were read using a microplate reader. Cells were excited at 488 nm, the green fluorescence was measured as emission at 527 nm, and the red fluorescence was measured as emission at 590 nm. The mitochondrial potentials were measured as the ratio of red to green fluorescence. Data presented as average +/- s.d. of n = 9 from three independent experiments. *, significantly lower than control.