Study of synergistic effect of free fatty acid and iron on the establishment of nonalcoholic fatty liver disease model

Abstract

To establish nonalcoholic fatty liver disease (NAFLD) model induced by free fatty acid (FFA) and iron, and to explore the synergistic effect of FFA and Fe(2+) on the pathogenesis of NAFLD and mechanisms. Human liver carcinoma cell HepG2 was respectively treated with 0.250, 0.500, 1.000 mmol/L oleic acid, 0.500 mmol/L oleic acid+0.125 mmol/L Fe(2+), 0.500 mmol/L oleic acid+0.250 mmol/L Fe(2+), and 0.500 mmol/L oleic acid+0.500 mmol/L Fe(2+). Human liver carcinoma cell HepG2 was normally cultured in the control group. Lipid accumulation of cells were observed by oil red O staining and the determination of the triglyceride (TG) contents by GPO-PAP, then the expression of key genes involved in fatty acid β-oxidation (fatty acyl CoA synthetase-1 (ACSL-1), carnitine acyl transferase 1 (CPT-1a), fatty acid synthetase (FAS)) was determined using RT-PCR. The differences of TG content and ACSL-1, CPT-1a, FAS, mRNA relative value were analyzed among different groups. The results of oil red O staining indicated that the contents of lipid droplets were obviously elevated with the increase of Fe(2+) concentration in human liver carcinoma cell HepG2 treated with 0.500 mmol/L oleic acid and different concentrations of Fe(2+). The TG contents of HepG2 cell in control group, 0.250, 0.500, 1.000 mmol/L oleic acid groups, 0.500 mmol/L oleic acid+0.125 mmol/L Fe(2+) group, 0.500 mmol/L oleic acid+0.250 mmol/L Fe(2+) group, 0.500 mmol/L oleic acid+0.500 mmol/L Fe(2+) group respectively were (90.0 ± 1.6), (131.7 ± 5.4), (153.7 ± 3.0), (254.1 ± 4.0), (164.5 ± 6.0), (180.1 ± 7.7), (235.6 ± 4.5) nmol/mg (F = 396.00, P < 0.05). The expression levels of ACSL-1 mRNA in 0.500 mmol/L oleic acid group, 0.500 mmol/L oleic acid+0.125 mmol/L Fe(2+) group, 0.500 mmol/L oleic acid +0.250 mmol/L Fe(2+) group, 0.500 mmol/L oleic acid +0.500 mmol/L Fe(2+) group respectively were (0.94 ± 0.02), (0.89 ± 0.04), (0.85 ± 0.02), (0.74 ± 0.04) (F = 50.00, P < 0.05); the mRNA levels of CPT-1a were (0.89 ± 0.03), (0.79 ± 0.05), (0.67 ± 0.04), (0.51 ± 0.05) (F = 79.00, P < 0.05); the mRNA levels of FAS were (1.31 ± 0.05) , (1.44 ± 0.03), (1.51 ± 0.05), (1.56 ± 0.06 ) (F = 79.70, P < 0.05). The NAFLD liver cell model could be established by oleic acid and Fe(2+) in HepG2 cells. FFA and iron might be involved in the pathogenesis of NAFLD through the intervention of fatty acid β-oxidation.