| Objective:Nonalcoholic fatty liver, the marker of nonalcoholic fatty liver disease (NAFLD), can develop into serious liver disease and threaten the health of human body heavily with its growing morbidity over the years. No chemical drugs was found to be effective for the treatment of nonalcoholic fatty liver at present, while traditional Chinese medicines (TCMs) are playing an more and more important role in clinical use for nonalcoholic fatty liver.Mangiferin, an active component extracted from TCMs, have been used for anti-inflammatory, antivirus, anti-tumor and the treat of diseases such as diabetes and obesity in a wide range for many years, while its mechanism is not clear. The HepG2 cell model was adopted in this study to investigate possible mechanism of mangiferin on triglyceride deposition in HepG2 cells induced by high-fructose, which can lay the theoretical foundation for further application of mangiferin in the treatment of nonalcoholic fatty liver.Methods:HepG2 cells were cultured in DMEM with low fructose concentration (1g/L glucose), and then the cells were divided into control group (1g/L glucose with no fructose), fructose group(1g/L glucose with 30 mmol/L fructose) and fructose+mangiferin with different concentrations (1g/L glucose and fructose of 30 mmol/L was mixed with mangiferin of different doses, whose final concentrations were 6.25 μmol/L,12.5 μmol/L, 25 μmol/L,50 μmol/L,100 μmol/L and 200 μmol/L) for 24h. After that, MTT method was used to seek for the most suitable concentration range of mangiferin. Under this concentration range, the lipid droplet deposition was observed by oil red O staining and the content of triglyceride (TG) was detected by enzymatic method. Real-time PCR was used to determine the mRNA expression of ChREBP, SREBP-1c, LPK and DGAT-2. All experimental data are expressed as mean ± standard deviation (SD). Comparisons between groups were tested by One-Way ANOVA analysis and LSD test, which was performed by SPSS 19.0 and p< 0.05 were considered statistically significant.Results:1. The result of MTT showed that there was almost no influence to cell vitality when the concentration of mangiferin was lower than 50μmol/L, while cell vitality declined with the increase of the concentration when it was higher than 50μmol/L. To eliminate the influence to cell vitality caused by drug toxicity, the concentration below 50μmol/L was used in the further experiment.2. Oil red O staining results revealed that, compared with control group, HepG2 cells in fructose group showed more lipid droplets. Low dose of mangiferin (6.25 μmol/L and 12.5 μmol/L) had no significant difference, while high dose of mangiferin (25 μmol/L and 50 μmol/L) decreased the lipid droplets significantly, and the dosage of 50 μmol/L mangiferin exhibited the best effect.3. Triglyceride enzyme method was applied to determine the content of triglyceride. Compared with that in control group, HepG2 cells in fructose group showed significantly higher content of triglyceride (P<0.05). Low dose of mangiferin had no difference, but high dose of mangiferin (25μmol/L and 50 μmol/L) reduced the content of triglyceride significantly (P<0.05), compared with fructose group, and the dosage of 50 μmol/L mangiferin had the best improve effect.4. By real-time PCR, compared with control group, the mRNA expressions of ChREBP, SREBP-1c, LPK, DGAT-2 increased significantly in fructose group, the mangiferin at 50μmol/L could down-regulate the overexpression of ChREBP, LPK, DGAT-2 mRNA (P<0.05). However, it showed minimal effect on SREBP-lc mRNA.Conclusion:1. Mangiferin can improve triglyceride deposition in HepG2 cells induced by high-fructose.2. The improvement is associated with inhibiting overexpression of lipid synthesis genes including ChREBP, LPK and DGAT-2. |
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