Upregulation of mRNA of retinoid binding protein and fatty acid binding protein by cholesterol enriched-diet and effect of ginger on lipid metabolism

Aims: We investigated whether a cholesterol enriched-diet Upregulated mRNA expression of the lipid metabolism related-proteins, retinoid binding protein (RBP), heart fatty acid binding protein (H-FABP), and cutaneous fatty acid binding protein (C-FABP), in liver and adipose tissue, and examined the effect of ginger on the expression of these genes. Main methods: The male rats were divided into 3 groups. Control rats were fed a standard diet, the cholesterol enriched-diet group (Chs) was fed a cholesterol enriched-diet. and the cholesterol enriched-diet and ginger group (ChGs) was fed a cholesterol enriched-diet and ginger (500 mg/day) diet, respectively for 12 weeks. Each mRNA expression level was measured as the ratio of each gene relative to the beta-actin expression level, using semi-quantitative RT-PCR method. Key findings: Cholesterol enriched-diet developed hepatic steatosis with hyperlipidemia and increased RBP mRNA expression in the liver, as well as mRNA expression of RBP, H-FABP, and C-FABP in adipose tissue around the left kidney (P<0.05). This is the first report to show the upregulation of H-FABP mRNA in adipose tissue in hyperlipidemic rats. RBP mRNA was expressed in the liver on ChGs slightly lower than Chs (P= 0.078). Significance: These lipid metabolism genes are important indicators of hyperlipidemia. Ginger tends to reduce RBP mRNA expression levels in the liver and visceral fat in hyperlipidemia, and may improve lipid metabolism. (C) 2009 Elsevier Inc. All rights reserved.