Abstract
Metabolic syndrome (MetS) can lead to increase of insulin resistance (IR) and visceral adipose tissue production of adipocytokines. 6-gingerol is known to have antioxidant and anti-inflammatory activities. Aim of this study is to investigate the effects of 6-gingerol on high-fat high-fructose (HFHF) diet-induced weight gain and IR in rats through modulation of adipocytokines. To induce MetS, male Sprague-Dawley rats were fed with a HFHF diet for 16 weeks and at Week 8, single-dose low-dose streptozotocin (22 mg/kg) were intraperitoneally injected. After 8 weeks of HFHF diet feeding, the rats were treated orally with 6-gingerol (50, 100, and 200 mg/kg/day) once daily for 8 weeks. At the end of the study, all animals were terminated, serum, liver, and visceral adipose tissues were harvested for biochemical analysis including the measurements of total cholesterol, triglycerides, HDL-cholesterol, fasting plasma glucose, insulin, leptin, adiponectin, proinflammatory cytokines (TNF-α and IL-6) and liver and adipose tissue histopathology. Biochemical parameters namely serum total cholesterol (243.7 ± 127.6 vs 72.6 ± 3 mg/dL), triglycerides (469.2 ± 164.9 vs 49.3 ± 6.3 mg/dL), fasting plasma glucose (334 ± 49.5 vs 121 ± 8.5 mg/dL), HOMA-IR (0.70 ± 0.24 vs 0.32 ± 0.06), and leptin (6.19 ± 1.24 vs 3.45 ± 0.33 ng/mL) were significantly enhanced, whereas HDL-cholesterol (26.2 ± 5.2 vs 27.9 ± 1.1 mg/dL) and adiponectin level (14.4 ± 5.5 vs 52.8 ± 10.7 ng/mL) were lowered in MetS vs normal control. Moreover, MetS were marked a significant increase in body weight and proinflammatory cytokines. Treatment with 6-gingerol dose-dependently restored all of those alterations towards normal values as well as the accumulation of lipid in liver and adipose tissues. These findings demonstrate that 6-gingerol, in a dose-dependent mode, showed capability of improving weight gain and IR in MetS rats through modulation of adipocytokines.