Oren-gedoku-to and Keishi-bukuryo-gan-ryo Inhibit the Progression of Atherosclerosis in Diet-Induced Hypercholesterolemic Rabbits

In this study, we examined whether the Kampo formulas Oren-gedoku-to (OGT, Huanglian-jie-du-tang in Chinese) and Keishi-bukuryo-gan-ryo (KBG, Gui-zhi-fu-ling-wan in Chinese) could prevent the progression of atherosclerosis in cholesterol-fed rabbit, an animal model for hypercholesterolemia in vivo. Twenty-four male Japanese white rabbits (2 kg body weight) were divided into four groups. The control group was fed standard rabbit chow containing 1% cholesterol, the OGT group was fed standard rabbit chow containing 1% cholesterol and 1% OGT, the KBG group was fed standard rabbit chow containing 1% cholesterol and 1% KBG, and the vitamin E group was fed standard rabbit chow containing 1% cholesterol and vitamin E (450 mg/1000 g). All four groups were kept on these diets for 8 weeks. At the end of the experiments, the percentage of surface area of the total thoracic aorta with visible plaque was significantly reduced in the OGT and KBG groups. The serum thiobarbituric acid reactive substances of the vitamin E group showed a significantly low value compared with the control group, whereas the serum lipid peroxide levels of the OGT and KBG groups were considerably lower than that of the control groups as well as that of the vitamin E group. Furthermore, the urinary 8-hydroxydeoxyguanosine levels of the OGT and KBG groups were considerably lower than that of the vitamin E group. These results suggest that OGT and KBG prevent the progression of atheromatous plaque by creating a sounder antioxidant defense system than vitamin E.