Effects and mechanism of epigallocatechin gallate on white adipose tissue angiogenesis in high fat diet rats

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. Key words: (-)-Epigallocatechin-3-gallate; High fat diet; White adipose tissue; Angiogenesis; Vascular endothelial growth factor