Oil red o dye solution

The BMSCs were cultured in 48-well plates (1×10⁴ cells/well) and irradiated after 24 h. The cells were subsequently induced with osteogenic or adipogenic induction medium (37°C; 5% CO₂). To estimate osteogenic differentiation, the cells were rinsed twice with PBS and fixed with 2.5% glutaraldehyde solution for 5 min. The cells were subsequently stained using an ALP staining kit, according to the manufacturer's protocol (Tiangen Biotech Co., Lrd., Beijing, China). To estimate the adipogenic differentiation, the cells were fixed with 4% paraformaldehyde (Sigma-Aldrich) solution and rinsed with PBS. The cells were gently rinsed with 60% isopropanol and the stained with Oil Red O dye solution (Sigma-Aldrich) for 30 min at room temperature. Following staining, the cells were visualized and images were captured using an optical microscope (Nikon 80i). Simple PCI imaging software (Compix, Inc., Arizona, USA) was used to count the number and areas of positively stained cells.

Human HepG2 cells were fixed with 10% paraformaldehyde for 30 minutes, and then stained with Oil Red O dye solution (Sigma-Aldrich, USA) for another 30 minutes. After washing with 60% isopropanol for 10 minutes, a microplate reader was used to quantify the steatosis of HepG2 cells by measuring absorbance at 510 nm wavelength.