Fig. 4

Effects of carnitine supplementation on mitochondrial membrane potential, lipid accumulation, and apoptosis of HepG2 cells. HepG2 cells were treated with or without 0.1 mM etomoxir or with 0.1 mM etomoxir + 0.2 mM L-carnitine for 24 h. Mitochondrial membrane potential (MMP, upper left panel) was analyzed using JC-1 staining and flow cytometry, and relative MMP is shown in the upper right panel. TG accumulation was evaluated via Oil Red O staining (middle of the left panel), and the relative density is shown in the middle of the right panel. Apoptotic HepG2 cells were stained with PI and annexin V and then analyzed via flow cytometry (lower portion of the left panel), and the number of apoptotic cells is shown in the lower part of the right panel. The oxygen consumption rate (OCR) was analyzed using a multifunctional microplate reader. Protein levels of Bax and Bcl-2 in HepG2 cells were analyzed after 24 h of treatment. Data from three independent experiments are shown as means ± SD. *, P < 0.05 and ***, P < 0.001 versus the control group; #, P < 0.05 and ###, P < 0.001 versus the etomoxir group