Comparative Study On Effects Of Black Tea Polyphenols And Grean Tea Polyphenols On Genes Related To Adipocyte Differentiation In Rats

Objective: In order to investigate the molecular mechanism of theanti-obesity effect of tea polyphenols and evaluate the comparativechemopreventive efficacy of green tea polyphenols (GTP) and black teapolyphenols (BTP).Metholds: In our experiments, rats were divided randomly into fourgroups: control group, high-fat group, high-fat diet with green teapolyphenols supplement group, and high-fat diet with black teapolyphenols supplement group. Food intake and body weights weredetermined twice per week. At the end of the third month, fasting bloodsamples were collected and analyzed for concentrations of serum lipidsby Automatic Analyser. The expression levels of those genes associatedwith adipocyte differentiation in epididymal adipose tissues weremeasured by real-time transcription-polymerase chain reaction.Results: 1. Both of two tea polyphenols treated groups completelyprevented the increase in body weight induced by high-fat diet; however,there is no statistical difference in body weight between the high-fat+GTP group and the high-fat +BTP group. 2. Both of two tea polyphenoltreatments prevented the increase in peritoneal and epididymal adiposetissues and liver tissue weights, however, no difference was found on thisaspect between green tea polyphenol and black tea polyphenol. 3. Plasmatotal cholesterol and LDL levels were lowered in both of two tea polyphenol treatments, while, the plasma total cholesterol level in thegreen tea polyphenol treatment group were less than that in black teapolyphenols treatment group. The plasma triglyceride level wasdecreased in the black tea polyphenols supplementation group whencompared with the high-fat group. 4. Both of GTP and BTPdown-regulated those adipocyte-specific genes, including adipocyteacid-binding protein 2, tumor necrosis factor-αand leptin. In addition,GTP also up-regulated the mRNA expression of the pre-adipocyemarker—pref-1 and reduced the mRNA expression of transcription factor,peroxisome proliferators-activated receptor (PPAR-γ).Conclusions:1. The results showed that both GTP and BTP prevented the increaseof body weight, liver and adipose tissue weights induced by high-fat diet.2. Both of GTP and BTP have effects on the concentrations of serumlipids, GTP showed more potent effect than BTP on the plasma totalcholesterol levels; BTP lowered the plasma triglyceride level while GTPdid not.3. It was suggested that tea polyphenols could prevent obesity atleast in part by reversing the adipocyte differentiation, and GTPpossessed stronger inhibitory effect than BTP.