Figure 2. Inhibitory effects of spirit vinegar and natural fermented vinegar products on lipid accumulation in fully differentiated 3T3-L1 adipocytes. 3T3-L1 preadipocytes were differentiated by adding adipogenic inducers (insulin, dexamethasone, and 3-isobutyl-1-methylxanthine) when the cells reached confluence, followed by 2 d of incubation. Complete differentiation to adipocytes was achieved by further culturing the cells in 10% FBS/DMEM with 5 μg/mL insulin for 4 d and then in 10% FBS/antibiotics/DMEM for 2 d. Vinegars were added during all stages of differentiation. (A) Intracellular triglycerides were stained with Oil Red O. (B) Oil Red O was dissolved with isopropanol, and optical density was measured at 520 nm. Values are presented as the mean ± SD (n =3). *p < 0.05, **p < 0.01, ***p<0.001 compared to the control