Oil Red O Staining and Cell Quantification

Oil Red O staining was carried out according to a previously described method [44]. 3T3-L1 cells were induced to differentiate as described above, washed three times with PBS, fixed with 10% formalin for 1 h, then stained with Oil Red O (0.5% in 60% isopropanol) for 30 min. Adipocytes were washed with 70% ethanol in water and then air-dried. Stained cells were visualized by light microscopy and imaged at 200× magnification. Oil Red O-stained lipids were dissolved with 100% isopropanol and absorbance at 490 nm was determined with a spectrophotometer.