[Role of 1, 25-dihydroxyvitamin D3 in liver lipid metabolism induced by methionine-choline-deficient diet in rats]

Objective: To investigate the role of 1, 25-dihydroxyvitamin D3 [1.25(OH) (2)D(3)] in liver lipid metabolism so as to provide the clues for elucidating the mechanism of non-alcoholic fatty liver. Methods: 26 SD rats were randomly divided into control group (methionine-choline-sufficient diet, MCS), model group (methionine-choline-deficiency diet, MCD) and intervention group [MCD+1.25(OH) (2)D(3)]. The intervention, control, and model group was given 3 ng/100 g 1.25(OH) (2)D(3) peanut oil solution per day by gavage according to body mass. After 4 weeks the experiment was ended up, and the blood was collected from the inferior vena cava to detect alanine aminotransferase (ALT) and aspartate aminotransferase (AST). The liver tissue was collected to observe the liver morphological and pathological changes (oil red O and HE staining). The changes in the level of liver total triglyceride (TG) content and liver lipid metabolism-related genes [fatty acid transfer protein (FAT/CD36), acetyl-coenzyme A carboxylase (ACC1)] mRNA and protein were detected. One-way analysis of variance was used to compare the means between groups. Results: Oil red O staining and HE staining showed that lipid droplet-vacuoles were significantly increased in the liver tissue of the model group than that of the intervention group. The liver TG content (2.23 ± 0.98) μmol/g of the intervention group was significantly lower than that of the model group (3.53 ± 1.06) μmol/g (F = 5.930, P = 0.035). The ALT content of the intervention group (35.99±9.54) U/L was significantly lower than that of the model group (57.65 ± 19.42) U/L (F = 13.790, P = 0.034). The AST content of the intervention group (16.9 ± 3.73) U/L was significantly lower than that of the model group (27.81 ± 13.31) U/L (F = 3.084, P = 0.046). The relative expression levels of mRNA and protein (mRNA: 1.21 ± 0.61, protein: 1.54 ± 0.75) of FAT/CD36 in the intervention group were significantly lower than those of the model group (mRNA: 2.31 ± 0.81, protein: 2.83 ± 1.42) (mRNA: F = 8.370, P = 0.001, protein: F = 7.212, P = 0.043). The relative expression level of mRNA and protein of ACC1 (mRNA: 0.89 ± 0.54, protein: 0.28 ± 0.11) were also significantly lower than those in model group (mRNA: 1.39 ± 0.19, protein: 0.47 ± 0.24) (mRNA: F = 3.948, P = 0.036, protein: F = 10.933, P = 0.048). Conclusion: 1.25(OH) (2)D(3) can reduce liver fat deposition in rats fed with MCD by inhibiting the expression of fat / CD36 and ACC1.