Protective effects of Saiko-ka-ryukotsu-borei-to (Chai-Hu-Jia-Long-Gu-Mu-Li-Tang) against atherosclerosis in Kurosawa and Kusanagi-hypercholesterolemic (KHC) rabbits

We investigated the protective effects of the traditional Japanese herbal m edicine Saiko-ka-ryukotsu-borei-to (Chai-Hu-Jia-Long-Gu-Mu-Li-Tang in Chine se) (SRBT) against hypercholesterolemia and atherosclerotic lesions. We foc used on atherosclerosis using female heterozygous Kurosawa and Kusanagi-hyp ercholesterolemic (KHC) rabbits. The total plasma cholesterol levels increa sed for up to 12 weeks after beginning a diet containing 0.1% cholesterol a nd then reached a plateau of about 600 mg dl(-1). When SRBT was administere d at a dose of 1.0 g kg(-1) per day for 24 weeks, total plasma cholesterol levels were significantly decreased after 20-24 weeks. On the other hand, p ravastatin at a dose of 10 mg kg(-1) per day produced a significant decreas e in total plasma cholesterol levels from 4 to 24 weeks (about 105-130 mg d l(-1)). Moreover, 1.0 g kg(-1) per day of SRBT significantly decreased plasma low d ensity lipoprotein (LDL) cholesterol levels but did not change either very low density lipoprotein (VLDL), or high density lipoprotein (HDL) cholester ol levels. Animals that received pravastatin had significantly decreased LD L cholesterol levels and VLDL cholesterol levels after 8 weeks and at 24 we eks. We also examined the expression of apoB, E and LDL receptor mRNA level s in the liver at 34 weeks after beginning the administration of 1.0 g kg(- 1) per day of SRBT. Both apoE and LDL receptor mRNA levels were significant ly increased compared with those in rabbits receiving the 0.1% cholesterol diet. SRBT at a dose of 1.0 g kg(-1) per day significantly depressed the in timal surface area of the thoracic aortae involved with atheromatous plaque s. The present results suggest that SRBT may protect against hypercholester olemia and atheromatous lesions by affecting apoE and LDL receptor mRNA gen e expression in the liver. (C) 2001 Academic Press.