Corn bran dietary fibre modified by xylanase improves the mRNA expression of genes involved in lipids metabolism in rats

The regulation effects of corn bran dietary fibre (CDF) and the xylanase modified form (XMF) in male Sprague Dawley rats on the expression of several genes involved in lipid metabolism were studied. Rats for NF and HF group (8 per group) were fed basic diet (NF) and atherogenic diet (HF), respectively, for six weeks. The rats for CDF or XMF group were fed HF diet, for two weeks first then changed to CDF (10%) or XMF (10%) diet, respectively, for four weeks. XMF ingestion lowered serum total cholesterol (TC), triacylglycerols (TG), low-density lipoprotein cholesterol (LDL-C) and increased high-density lipoprotein cholesterol (HDL-C) significantly (p < 0.05) as compared with CDF; The corresponding liver TC, TG and fat in XMF group were also significantly lower (p < 0.05). CDF ingestion lowered serum TC, TG, LDL-C, arteriosclerosis index (AI), and liver fat significantly (p < 0.05). AI in XMF group was less than 50% of that in CDF group. XMF enhanced the catabolism of lipids by up-regulating the transcription of hepatic cholesterol 7 alpha-hydroxylase (CYP7A1), peroxisome proliferator-activated receptors (PPARα and PPARγ), lipoprotein lipase (Lpl), liver lipase and ileum farnesoid X receptor (FXR), down-regulating the transcription of intestine-bile acid binding protein (I-BABP) and hepatic FXR. While CDF only down-regulated I-BABP transcription, up-regulated ileum FXR, liver PPARα, Lpl and CYP7A1 transcription.