Hepatic-specific vitamin D receptor downregulation alleviates aging-related metabolic dysfunction-associated steatotic liver disease

Figure 1 Establishment of a cellular senescence model and aggravation of steatosis in senescent cells. A: HepG2 and AML12 cells were treated with hydrogen peroxide (H₂O₂) (400 μM) for 6 hours and stained for β-galactosidase (× 400); B: HepG2 and AML12 cells were irradiated with 8 Gy of X-rays and stained for β-galactosidase (× 400); C-F: Protein expression levels of P16, P21, and P53 and corresponding quantitative results, and mRNA levels of P16, P21, and P53 in HepG2 and AML12 cells after cellular senescence was established; G: Cellular levels of triglycerides (TGs) and Oil Red O staining (× 400) of AML12 cells treated with H₂O₂ (400 μM) for 6 hours and stimulated with different concentrations of palmitic acid (PA) (100 μM, 200 μM, or 300 μM) for 24 hours; H: Cellular levels of TGs and Oil Red O staining (× 400) of AML12 cells irradiated with 8 Gy of X-rays and stimulated with different concentrations of PA (100 μM, 200 μM, or 300 μM) for 24 hours; I: Cellular levels of TGs and Oil Red O staining (× 400) of AML12 cells irradiated with 8 Gy of X-rays and stimulated with different concentrations of free fatty acids (0.6 mmol/L, 0.8 mmol/L, or 1 mmol/L) for 24 hours. Protein levels and mRNA levels were normalized to glyceraldehyde-3-phosphate dehydrogenase. The data are presented as the means ± SDs. ^aP < 0.05. ^bP < 0.01. ^cP < 0.001. P calculated according to student’s t tests. H₂O₂: Hydrogen peroxide; NC: Negative control; BSA: Bovine serum albumin; SA-β-Gal: Senescence-associated β-galactosidase; PA: Palmitic acid; FFA: Free fatty acids; GAPDH: Glyceraldehyde-3-phosphate dehydrogenase.