Effects Of Tea Polyhenols On Obese Rats Induced By Olanzapine And Its Mechanism

Objective:To investigate the weight-reduction effects of tea polyphenols (TP) on obese rats induced by olanzapine and its mechanism.Methods:The Seventy female SD rats were randomized into 2 groups,10 in the control group and 60 in the obese model group. The obese model rats received olanzapine(1.2 mg/kg) daily via gavage 1 h before the beginning of the dark-phase for 2 weeks, while the control group received an equivalent volume of distilled water. The obese model rats were randomized into 4 groups,10 in each group. They are model group, sibutramine hydrochloride group(2.5 mg/kg), TP low-dose(150 mg/kg)and high-dose(300 mg/kg) group. Except the control group, all rats were administered with olanzapine continuously. TP and sibutramine hydrochloride were given by gavage for 5 weeks. Body weight was measured each week and the amount of food and water were detected twice one week. After 5 weeks administration with TP, spontaneous activity was monitored continuously using the SMART video-tracking system during the light and dark phase; the naso-anal length and the fat weight around the kidney and uterus of each rat were recorded, Lee's index and fatty coefficient were calculated respectively; DA, DOPAC, HAV,5-HT,5-HIAA and NA in the hypothalamus were measured by high performance liqiud chromatography coupled with electrochemical detector (HPLC-ECD); The level of serum leptin and ADP were determined by the ELISA KIT; The level of serum blood lipids, glucose, insulin, ALT, AST, SOD activity and MDA content were measured through different methods.1. Compared with control group, the body weight, the amount of food, Lee's index.fat weight and fatty coefficient were significantly increased (P<0.05,P<0.01) in model group; Average speed and distance during the dark phase were significantly decreased(P<0.05); 5-HT, DA and DOPAC in the hypothalamus were significantly increased (P<0.05, P<0.01); serum leptin content was significantly increased and adiponectin content was significantly decreased (P<0.01); serum FFA content was significantly increased(P<0.05) in model group. 2.Compared to model group, the body weight, the intaken amount of food and water, Lee's index,fat weight and fatty coefficient were significantly decreased (P<0.05, P<0.01) in TP groups, Average speed and distance during the dark phase were significantly increased (P<0.05,P<0.01); DA and DOPAC in the hypothalamus were significantly decreased and NA and 5-HIAA were significantly increased (P <0.01), serum FFA and LDL-C content were significantly decreased (P<0.05), serum SOD activity was significantly increased and MDA content was significantly decreased (P<0.05, P<0.01) in TP group; Move fast time was significantly increased and rest time was significantly decreased during the dark phase(P<0.05) for low-dose group of TP, and serum TC content was significantly decreased(P<0.05) and serum adiponectin content was significantly increased(P<0.05) for high-dose group of TP.1. The obese rats model was reproduced successfully by olanzapine (1.2mg/kg) via gavage.2. TP can significantly lower body weight of obese rats induced by olanzapine through decreasing the amount of food and water intaken and increasing animal spontaneous activity.3. For the obese rats induced by olanzapine, weight-reduction of TP may be concerned with the decreasing DA and DOPAC and increasing NA and 5-HIAA in the hypothalamus.4. Increasing serum level of adiponectin may contrubite to the weight-reduction of TP in this obese model.