Objective • To explore the effect of epigallocatechin-3-gallate (EGCG) on oxidative stress and inflammation in 3T3-L1 adipocytes, and provide a theoretical basis for EGCG to prevent obesity and related chronic diseases. Methods • 3T3-L1 preadipocytes were differentiated to mature adipocytes by in vitro cell culture. The cells were divided into blank control group, and 1, 10 and 50 μg/mL EGCG groups. After 24 hour treatment, intracellular oxidative stress indicators glutathione (GSH), superoxide dismutase (SOD), and malondialdehyde (MDA) levels in the cells were measured. The levels of inflammatory indexes interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and monocyte chemoattractant protein-1 (MCP-1) were tested by ELISA and realtime PCR, while the expression of nuclear factor E2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) was tested by realtime PCR. Results • Compared with the control group, GSH and SOD levels in 3T3-L1 adipocytes increased in a dose-dependent manner after treatment of EGCG (both P<0.05), while MDA level in 3T3-L1 adipocytes decreased dose-dependently after treatment of EGCG (P<0.05). IL-6, MCP-1 and TNF-α levels in 3T3-L1 adipocytes supernatant declined significantly in a dose-dependent manner after treatment of 1, 10 and 50 μg/mL EGCG (all P<0.05). The expression levels of IL-6, MCP-1 and TNF-α in 3T3-L1 adipocytes were decreased in a dose-dependent manner after 24 h treatment of different concentrations of EGCG. Nrf2 and HO-1 mRNA levels in 3T3-L1 adipocytes increased significantly in a dose-dependent manner after treatment of 10 and 50 μg/mL EGCG (both P<0.05). Conclusion • EGCG plays an antioxidation and anti-inflammatory effects in 3T3-L1 adipocytes, which may be related to up-regulation of Nrf2/HO-1.

Objective To investigate the effects and mechanism of (-)-epigallocatechin-3-gallate (EGCG) on white adipose tissue angiogenesis in high fat diet rats.Methods Twenty-four male weaning SD rats were randomly divided into normal control group,high fat diet group and EGCG intervention group,8 rats in each group.Normal control group were fed with normal diet,high-fat diet group were fed with high-fat diet,EGCG intervention group were fed with high-fat diet along with intragastric administration of 200 mg/ (kg · d) EGCG.After 8 weeks,the rats were sacrificed.The adipocyte size and vascular density of the abdominal adipose tissue in rats in each group were observed under the microscope.The serum vascular endothelial growth factor (VEGF) concentration was detected by Elisa Kit.RT-PCR was used to detect the expression of VEGF,nuclear factor E2 (Nrf2),heme oxygenase-1 (HO-1),catalase (CAT),SOD,GPx,interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1) mRNA.Results The adipocyte size,number of vascular/each adipocyte,serum VEGF concentration and VEGF mRNA expression in adipose tissue of high fat diet group were significantly higher than those of normal control group (all P＜0.05).EGCG can significantly reduce the above indicators of high fat diet group (all P＜0.05).The expression of Nrf2,HO-1,SOD,GPx and CAT mRNA in adipose tissue of EGCG group was significantly higher than those in high fat diet group and normal control group (all P＜0.05).The expression of MCP-1 and IL-6 mRNA in adipose tissue of EGCG group was significantly lower than that in high fat diet group (all P＜0.05).Conclusion EGCG can decrease the production of serum VEGF,vascular density and the expression of VEGF mRNA in white adipose tissue of high fat diet rats,and inhibit the angiogenesis in white adipose tissue possibly due to its up-regulation of Nrf2/HO-1 pathway to increase the expression of antioxidant enzymes (SOD,CAT,GPx),reduce ROS production and decrease the inflammatory response.