3T3-L1 지방세포주에서 Epigallocatechin gallate가 세포증식 및 분화에 미치는 영향

Abstract

Green tea extracts contain many biologically-active materials, including catechins. The major water extractable component is epigallocatechin gallate (EGCG). (-)-Catechin at a higher concentration (50 μM) is also reported to be beneficial against obesity, by increasing adiponectin secretion from adipocytes. However, readily-achievable dose of EGCG in human blood after regular daily oral ingestion is around 1 μM, and (-)-catechin concentration is known to be further less than EGCG. Therefore, this study was designed to see whether they are real positive effecters against obesity at physiological blood levels, using a mouse adipocyte cell line, 3T3-L1. 3T3-L1 preadipocytes in Dulbecco's modified Eagles's medium (DMEM) media were differentiated by a serial 2-day addition method of isobutylmethylxanthine (IBMX), dexamethasone and insulin solution (Day 1 & 2) and insulin solution (Day 3 & 4). Each EGCG and (-)-catechins at concentrations between 0.1-10 μM was applied everyday from Day 1. Mitotic clonal expansion and expression level of C/EBPβwere measured at day 2, 2 days after the MDI treatment. Oil red-O staining was performed at Day 7, 8, 11. Adiponectin secretion measurement and Western blot for adiponectin and PPARγwere done at Day 8. EGCG and (-)-catechins were not influential in clonal expansion and C/EBPβprotein expression. Triglyceride accumulation in mature adipocytes tended to increase in EGCG-treated group, but not in (-)-catechins group. Adiponectin secretion was not modified in EGCG and (-)- catechin-treated groups. In addition, the two catechins did not significantly change the protein expression level of adiponectin and PPARγ. These may suggest that there is no direct evidence that EGCG has a mechanism in adipocytes, applicable to preventing from obesity by a daily regular consumption.