Numerous studies have suggested that hyperlipidemia is closely linked to cardiovascular disease. The aim of this study was to investigate the possible antihyperlipidemia mechanism of HU (high sulfate content of ulvan) in high-cholesterol fed rats. Wistar rats were made hyperlipidemic by feeding with a high-cholesterol diet. HU was administered to these hyperlipidemia rats for 30 days. Lipid levels and the mRNA expressions of FXR, LXR and PPARγ in liver were measured after 30 days of treatment. In the HU-treated groups, the middle dosage group of male rats (total cholesterol (TC): p < 0.01) and the low-dosage group of female rats (TC, LDL-C: p < 0.01) showed stronger activity with respect to antihyperlipidemia. Moreover, some HU groups could upregulate the mRNA expression of FXR and PPARγ and downregulate the expression of LXR. For the male rats, compared with the hyperlipidemia group, the middle dosage HU had the most pronounced effect on increasing the mRNA levels of FXR (p < 0.01); low- and high-dosage HU showed a significant inhibition of the mRNA levels of LXR (p < 0.01). All HU female groups could upregulate the mRNA expression of PPARγ in a concentration-dependent manner. In summary, HU could improve lipid profiles through upregulation of FXR and PPARγ and downregulation of LXR.
Keywords: Ulva pertusa; antihyperlipidemic; mechanism; sulfated polysaccharide.