The efficacy of different doses of vitamin C in prevention and treatment of non-alcoholic fatty liver disease in mice

Objective To investigate the efficacy of different doses of vitamin C (VC) in prevention and treatment of non-alcoholic fatty liver disease (NAFLD) in mice. Methods C57BL/6 mice were fed with high-fat diet to establish NAFLD models. The experimental animals were divided into early prevention and later treatment groups. Both of these two experimental processes had five subgroups, including control, high-fat diet (HFD), low-dose vitamin C (LD-VC, 15 mg/kg per day), medium-dose vitamin C (MD-VC, 30 mg/kg per day) and high-dose vitamin C (HD-VC, 90 mg/kg per day) subgroup, with six mice in each subgroup. In the early prevention group, the mice were prophylactically received VC for 12 weeks. In the later treatment group, the mice were treated with different dose of VC for 12 weeks after fed with HFD for six weeks and confirmed NAFLD by liver pathology. The differences in body weight, perirenal adipose tissue mass and serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol (TC), and triacylglycerol (TG) were observed among different groups. The scores of hepatocyte steatosis, lobular inflammation and ballooning in liver histopathology of mice in each group were evaluated by non-alcoholic fatty liver disease activity score (NAS) scoring system. Tukey′s multiple comparison test and Kruskal-Wallis H test were performed for statistical analysis. Results In the early prevention group, the body weight, perirenal adipose tissue mass, TG level and the score of liver steatosis of LD-VC subgroup were all lower than those of HFD subgroup ((30.27±0.94) g vs. (32.18±1.35) g, (0.25±0.05) g vs. (0.32±0.02) g, (0.25±0.02) mmol/L vs. (0.30±0.03) mmol/L, 0 vs. 1.0(1.0)). The body weight, perirenal adipose tissue mass, blood glucose level, TG level and score of liver steatosis of MD-VC subgroup were all lower than those of HFD subgroup ( (29.72±0.58) g vs. (32.18±1.35) g, (0.24±0.05) g vs. (0.32±0.02) g, (6.93±0.59) mmol/L vs. (8.33±1.02) mmol/L, (0.24±0.04) mmol/L vs. (0.30±0.03) mmol/L, 0 vs. 1.0(1.0)); meanwhile, the blood glucose level and TG level of HD-VC subgroup were both lower than those of HFD subgroup ((6.72±0.59) mmol/L vs. (8.33±1.02) mmol/L, (0.23±0.04) mmol/L vs. (0.30±0.03) mmol/L), and the differences were statistically significant (all P<0.05). In the later treatment group, TG level of LD-VC subgroup was lower than that of HFD subgroup ((0.25±0.07) mmol/L vs. (0.37±0.06) mmol/L); the body weight, perirenal adipose tissue mass, blood glucose level, TG level and liver steatosis score of MD-VC subgroup were lower than those of HFD subgroup ((29.93±1.28) g vs. (33.24±2.45) g, (0.29±0.08) g vs. (0.53±0.14) g, (7.63±0.57) mmol/L vs. (9.13±1.52) mmol/L, (0.23±0.03) mmol/L vs. (0.37±0.06) mmol/L, 0.5(1.0) vs. 2.0(1.0)); the blood glucose level and TG level of HD-VC subgroup were both lower than those of HFD subgroup ((7.20±0.72) mmol/L vs. (9.13±1.52) mmol/L, (0.19±0.03) mmol/L vs. (0.37±0.06) mmol/L); however the body weight, liver weight, perirenal adipose tissue mass and lobular inflammation score of HD-VC subgroup were all high than those of HFD subgroup( (36.34±2.44) g vs. (33.24±2.45) g, (1.18±0.07) g vs. (1.06±0.09) g, (0.78±0.17) g vs. (0.53±0.14) g, 1.0(1.0) vs.0(1.0)), and the differences were statistically significant (all P<0.05). The body weight, perirenal adipose tissue mass and the score of liver steatosis, lobular inflammation and ballooning of LD-VC subgroup of the early prevention group were all lower than those of LD-VC subgroup of the later treatment group ((30.27±0.94) g vs. (34.75±1.64) g, (0.25±0.05) g vs. (0.61±0.14) g, 0 vs.1.5(1.0), 0 vs. 0.5(1.0), 0 vs. 1.0(0)); and the body weight, liver weight, perirenal adipose tissue mass, ALT level, AST level and scores of liver steatosis and lobulor inflammation of HD-VC subgroup of the early prevention group were all lower than those of HD-VC subgroup of the late treatment group ((31.78±0.71) g vs. (36.34±2.44) g, (1.01±0.02) g vs. (1.18±0.07) g, (0.30±0.05) g vs. (0.78±0.17) g, (8.83±0.98) U/L vs. (12.75±2.05) U/L, (29.00±4.19) U/L vs. (41.88±14.36) U/L, 1.0(0) vs. 2.5(1.0), 0 vs. 1.0(1.0)), and the differences were statistically significant (all P<0.05). Conclusions MD-VC can prevent the occurrence of NAFLD in mice at an early stage, and it is also benefit to the later treatment of NAFLD in mice. However, HD-VC has potential risks in early prevention and later treatment of NAFLD in mice. Key words: Non-alcoholic fatty liver disease; Vitamin C; Prevention; Treatment; Mice