OBJECTIVETo observe the effect of Pi transportation, dampness resolving and phlegm expelling herbs (PTDRPEH) on the obesity degree, fat hormones, and leptin resistance in diet-induced obesity (DIO) rats.

METHODSAmong the 120 Wister rats, 10 were recruited as the blank control group (fed with basal forage), and the remaining 110 were administered with high-fat high-nutrition forage for 17 weeks. According to weight, we obtained 40 DIO rats and 10 diet-induced obesity resistance (DIO-R) rats. DIO rats were further divided into four groups, i.e., the DIO model group (normal saline, at the daily dose of 2 mL), the sibutramine group (at the daily dose of 1.6 mg/kg), the dampness resolving and phlegm expelling group (DRPE, at the daily dose of 3.2 g/kg), and the Pi transportation group (PT, at the daily dose of 3.2 g/kg). All were given by gastrogavage. Normal saline (2 mL) was given by gastrogavage to rats in the blank control group and the DIO-R group. The basal forage was administered to rats in the blank control group, while high fat forage was continually given to rats in the remaining five groups. Their body weights and body lengths were measured after 16 weeks of gastrogavage. All intra-abdominal fat was taken out to measure the degree of obesity and fat contents. Insulin resistance index (IRI), blood glucose, triglycerides, cholesterol, leptin, neuropeptide Y (NPY), tumor necrosis factor alpha (TNF-alpha), and adiponectin were detected after blood withdrawing. Leptin, TNF-alpha, adiponectin, suppressors of cytokine signaling-3 (SOCS-3), and other relevant adipose hormones and inflammatory cytokines were examined in the fat homogenate.

RESULTSCompared with the blank control group, DIO model rats' body weight, body mass index (BMI), fat factor, IRI, serum leptin, TNF-alpha, and SOCS-3 significantly increased (P < 0.05, P < 0.01); serum NPY, serum leptin, and adiponectin decreased (P < 0.05). Leptin increased and NPY decreased in DIO-R model rats. Compared with the DIO group, DIO-R model rats' body weight, BMI, fat factor, IRI, serum NPY, TNF-alpha, and SOCS-3 all decreased (P < 0.05, P < 0.01); leptin and adiponectin in serum and the fat homogenate all increased (P < 0.05, P < 0.01). After intervention with Sibutramine, rats' body weight, BMI, fat factor, and TNF-alpha in the fat homogenate obviously decreased (P < 0.05, P < 0.01). Serum TNF-alpha decreased, leptin and adiponectin increased in rats of the DRPE group (P < 0.05, P < 0.01). BMI, fat factor, IRI, leptin, and SOCS-3 showed a decreasing tendency, but with no statistical difference (P > 0.05). The body weight, BMI, fat factor, IRI, TNF-alpha, and SOCS-3 all decreased in the PT group (P < 0.05, P < 0.01); leptin and adiponectin in the serum and the fat homogenate increased (P < 0.05, P < 0.01).

CONCLUSIONSSibutramine could reduce body weight and TNF-alpha in the adipose tissue. Herbs of PT could inhibit fat diet-induced obesity and insulin resistance (IR), with superior effect to herbs of DRPE. Its mechanism might be closely related to promoting leptin and adiponectin secreted by fat, reducing leptin resistance, and elevating serum levels of leptin and adiponectin.