ABSTRACT
Objective To explore the effects of phytosterol ester (PSE) on the hepatic steatosis and amino acid profile of rats with non-alcoholic fatty liver disease (NAFLD) induced by high fat diet. Methods Thirty-one male SD rats were randomly divided into normal control group (NC group, n＝7), high fat diet group (HF group, n＝12) and PSE intervention group (PSE＋HF group, n＝12). The rats in the HF and PSE＋HF groups were fed with high-fat diet to establish the NAFLD rat model, and the rats in the PSE＋HF group were continuously intragastrically administered with PSE 0.5 g/kg for 12 weeks. The hepatic steatosis was evaluated with Oil Red O staining, and the serum amino acid profile was analyzed using automatic amino acid analyzer. Pearson correlation analysis was used to investigate the correlation between amino acids and degree of liver steatosis. Partial least squares-discriminant analysis (PLS-DA) was carried out using SIMCA-P 11.5 software. Results There was no significant difference in body mass of rats between the PSE＋HF group and HF group (P0.05). Moreover, there was no significant difference in food intake of rats between the NC, HF and PSE＋HF groups (P0.05). Compared with the HF group, the hepatic steatosis of rats was partly alleviated in the PSE＋HF group. The serum levels of essential amino acids, including isoleucine and leucine, and the non-essential amino acids, including cysteine, aspartate, glutamate and alanine, in the PSE＋HF group were increased by 17.25%, 12.42%, 41.47%, 15.61%, 17.87% and 16.07%, respectively, compared with the HF group, and the differences were statistically significant (all P0.05). The levels of serum NH3 and histidine were significantly decreased in the PSE＋HF group versus the HF group (both P0.05). PLS-DA analysis results showed that HF group and PSE＋HF group could be clustered respectively. Pearson correlation analysis results showed that the levels of histidine, proline and serum NH3 were positively correlated with the degree of hepatic steatosis (all P0.01); and tryptophan, phenylalanine, isoleucine, cysteine, glutamate and the related metabolites, ornithine, were negatively correlated with the degree of hepatic steatosis (all P0.05). Conclusion PSE can regulate the amino acid metabolic profile of rats with NAFLD induced by high fat diet.