Pan SY, Dong H, Guo BF, Zhang Y, Yu ZL, Fong WF, Han YF, Ko KM
 Department of Pharmacology, Beijing University of Chinese Medicine, Beijing, China.
 School of Chinese Medicine,Hong Kong Baptist University,Hong Kong SAR, China.
 Department of Applied Biology & Chemical Technology, Hong Kong Polytechnic University, Hong Kong SAR, China.
 Division of Life Science, Hong Kong University of Science & Technology, Hong Kong SAR, China.
Schisandrin B, an active ingredient isolated from the fruit of Schisandra chinensis, increased serum and hepatic triglyceride levels in mice. In the present study, the effective kinetics of schisandrin B on serum/hepatic triglyceride and total cholesterol levels in mice without and with the influence of fenofibrate were investigated. Parameters on hepatic index (the ratio of liver weight to body weight × 100) were also analyzed. Mice were intragastrically treated with schisandrin B at a single dose of 0.2, 0.4, 0.8, or 1.6 g/kg, without or with fenofibrate pretreatment (0.1 g/kg/day for 4 days, p.o.). Twenty-four hours after schisandrin B treatment, serum/hepatic triglyceride and total cholesterol levels were measured. Schisandrin B treatment dose-dependently increased serum and hepatic triglyceride levels as well as hepatic index in mice. In contrast, hepatic total cholesterol levels were decreased in a dose-dependent manner in schisandrin B-treated mice. Data obtained from effective kinetics analysis indicated that the action of schisandrin B on serum triglyceride had a higher specificity than those on hepatic total cholesterol and hepatic index. While fenofibrate pretreatment inhibited the schisandrin B-induced elevation in serum triglyceride levels, it completely abrogated the elevation of hepatic triglyceride levels in schisandrin B-treated mice. The combined treatment with schisandrin B and fenofibrate decreased hepatic total cholesterol level and increased the hepatic index in an additive or semi-additive manner, respectively. In conclusion, the results of effective kinetics analysis indicated that the schisandrin B-induced hypertriglyceridemia was competitively inhibited by fenofibrate. Schisandrin B may offer the prospect of setting up a mouse model of hypertriglyceridemia and fatty liver for screening triglyceride-lowering drug candidates.