Effects of Dai-saiko-to (Da-Chai-Hu-Tang) on plasma lipids and atherosclerotic lesions in female heterozygous heritable Kurosawa and Kusanagi-hypercholesterolemic (KHC) rabbits.

We investigated the antihypercholesterolemic effects of traditional Japanese herbal medicine Dai-saiko-to (Da-Chai-Hu-Tang in Chinese) in female heritable Kurosawa and Kusanagi-hypercholesterolemic (KHC) rabbits. The plasma total cholesterol levels increased for up to 12 weeks after beginning a diet containing 0.1% cholesterol then reached a plateau of about 603 mg dl(-1). Dai-saiko-to was administered at doses of 0.5-1.0 g kg(-1) per day or pravastatin 10 mg kg(-1) per day for 24 weeks. Plasma total cholesterol levels were significantly decreased in the groups administered Dai-saiko-to 1.0 g kg(-1) per day or pravastatin for 4-24 weeks, whereas there were no change with plasma phospholipid and triglyceride levels. However, Dai-saiko-to 1.0 g kg(-1) per day significantly decreased plasma LDL cholesterol levels, but had no effect on either VLDL- or HDL-cholesterol levels. Moreover, LDL-receptor mRNA levels in the liver were significantly increased in the Dai-saiko-to 1.0 g kg(-1) per day group compared with those of animals receiving the 0.1% cholesterol diet. In addition, both groups receiving Dai-saiko-to 1.0 g kg(-1) per day and pravastatin showed a significantly reduced percentage of intimal surface area of thoracic aorta involved with atheromatous plaques in the thoracic aorta at 24 weeks. These results indicated that Dai-saiko-to 1.0 g kg(-1) per day significantly decreased the plasma cholesterol levels and atheromatous plaque area due to expression of the LDL mRNA gene in the liver.