Gene expression analysis of the liver and skeletal muscle of psyllium-treated mice

Abstract

Psyllium, a dietary fibre rich in soluble components, has both cholesterol- and TAG-lowering effects. Many studies have verified these actions using liver samples, whereas little information is available on the effects of psyllium treatment on other organs. The purpose of the present study was to evaluate the possible beneficial effects of psyllium. We investigated the gene expression profiles of both liver and skeletal muscle using DNA microarrays. C57BL/6J mice were fed a low-fat diet (LFD; 7 % fat), a high-fat diet (HFD; 40 % fat) or a HFD with psyllium (40 % fat+5 % psyllium; HFD+Psy) for 10 weeks. Body weights and food intake were measured weekly. After 10 weeks, the mice were killed and tissues were collected. Adipose tissues were weighed, and plasma total cholesterol and TAG blood glucose levels were measured. The expression levels of genes involved in glycolysis, gluconeogenesis, glucose transport and fatty acid metabolism were measured by DNA microarray in the liver and skeletal muscle. In the HFD+Psy group, plasma total cholesterol, TAG and blood glucose levels significantly decreased. There was a significant reduction in the relative weight of the epididymal and retroperitoneal fat tissue depots in mice fed the HFD+Psy. The expression levels of genes involved in fatty acid oxidation and lipid transport were significantly up-regulated in the skeletal muscle of the HFD+Psy group. This result suggests that psyllium stimulates lipid transport and fatty acid oxidation in the muscle. In conclusion, the present study demonstrates that psyllium can promote lipid consumption in the skeletal muscle; and this effect would create a slightly insufficient glucose state in the liver.