Intervention effect of resveratrol (RES) on morphological changes and intracellular lipid accumulation under high-fatty-acid conditions. HepG2 cells were treated with different concentrations of (A) RES (0–100 µM) for 6 h and (B) Free fatty acid (FFA) (0–300 µM) for 24 h. Cell proliferation was measured by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. (C) HepG2 cells were pretreated with/without RES (100 µM) for 6 h and then cultured with/without FFA (100 µM) with 0.1% bovine serum albumin (BSA) for 24 h. Morphological changes of HepG2 cells were determined using an inverted microscope (×400). Lipid accumulation of HepG2 cells was determined by Oil Red O staining, qualitatively analyzed using an inverted microscope (×200) (D), and quantitatively analyzed using a microplate reader (492 nm) (E). Relative cellular levels of (F) total cholesterol (T-CHO) and (G) triglycerides (TG) were detected using corresponding kits. Data were presented as the mean ± SD, n ≥ 3. (∗) p < 0.05 and (∗∗) p < 0.01, versus control group; (#) p < 0.05 and (##) p < 0.01, versus FFA group.