Abstract
Dai-Saiko-To (D-ext) has been noted to exhibit anti-atherogenesis. Following administration, New Zealand White (NZW) rabbit aortas were studied to determine the drug's effect against atherosclerosis induced by a rations high in cholesterol. A total of 101 NZW rabbits were divided into: Group A (experimental group): D-ext administration (1, 000mg/kg body weight/day, Tsumura, Tokyo) for 1 or 2 years after giving feed containing 1.5% cholesterol for 3 months; Group B (control): Received a normal diet (vehicle, CR-1, CLEA JAPAN, INC., Tokyo) for 1 or 2 years after the same atherogenic diet; Group C: Received a normal diet through experimental periods; Group D (hypercholesterol group) Received the same atherogenic diet for 3 months; Group E (simultaneous group): Received feed contaming 1.5% cholesterol and D-ext simultaneously for 3 months. Body weight, levels of serum total cholesterol (TC), triglyceride (TG), and cholesterol ester (CE) were periodically monitored until sacrifice. Serum lipids and aortic tissue lipids were analyzed, and aortas were processed for pathological analysis, including Surface Involvement (SI) and Atherosclerotic Index (AI).
After 2-year administration of D-ext, the elevated levels of serum TC dropped back to the same level as at the start of the experiment. There was no significant difference in serum TC between groups A and B, but serum TG in group A at 3 and 6 months was significantly lower than in group B. The values of CE in group A aorta decreased relative to group B, though the difference was not significant. FC/PL ratios in the aortic intima-medial components of the group A tended to be lower than in the group B. AI in the group A at 6 months administration of D-ext was significantly lower than in the group B, and group E showed a significant lowering of AI compared to group D. There was no significant difference in SI among the groups. Histologically, lesions in group A had fewer foam cells, and the intimal thickness was thinner than in group B.
Two-year administration of D-ext was less effecfive against advanced atherosclerosis induced by 1.5% cholesterol. But, D-ext exhibited a lowering of serum TG, aortic CE, and FC/PL ratios in the intima-medial cellular component. D-ext may have anti-atherogenesis in the progression of atherosclerosis in NZW rabbit aorta.
