Gene Expression Profile in the Liver Tissue of High Fat Diet-Induced Obese Mice

The purpose of this study was to investigate the gene profiles that were up- or down-regulated in the livers of high-fat diet-induced obese mice and $db_-/db_-$ mice with deficient leptin receptor. C57/BL6 normal mice and $db_-/db_-$ mice, respectively, were divided into two groups and fed a standard or high-fat diet for four weeks. Liver weight was unchanged in the normal mice but the high-fat diet led to a 10% weight increase in the $db_-/db_-$mice. Adipose tissue mass increased by about 88% in the normal mice that were fed a high-fat diet and by about 17% in the $db_-/db_-$mice on the high-fat diet. In terms of serum lipids, total cholesterol significantly increased in mice on the high-fat diet. Microarray analysis was carried out using total RNA isolated from the livers of standard or high-fat diet-fed mice of the normal and $db_-/db_-$ strains. The change of gene expression was confirmed by RT-PCR. About 1.6% and 6.8% of total genes, respectively, showed different expression patterns in the normal mice fed the high-fat diet and $db_-/db_-$ mice. As a result of microarray, many genes involved in metabolism and signal pathways were shown to have different expression patterns. Expression of Mgst3 gene increased in the livers of normal and $db_-/db_-$ mice that were fed a high-fat diet. Wnt7b and Ptk9l were down-regulated in the livers of the normal mice and $db_-/db_-$ mice that were fed a high-fat diet. In conclusion, a high-fat diet induced obesity and affected gene expression involved in metabolism and signal pathway.