Oil Red O Staining

After 3T3-L1 precursor adipocytes had differentiated for 9 days, the medium was removed. Next, the cells were fixed with 10% formaldehyde, and washed again with PBS. Then, Oil red O solution was added, and cells were stained at room temperature (RT) for 30 min. After removing the Oil red O solution, cells were washed with distilled water (DW), dried, and observed with a phase contrast microscope. Finally, the stained lipid droplets were dissolved in 100% isopropyl alcohol, and the absorbance was measured at 510 nm.