Green tea polyphenol epigallocatechin gallate inhibits adipogenesis and induces apoptosis in 3T3-L1 adipocytes.
OBJECTIVE
Green tea catechins have been shown to promote loss of body fat and to inhibit growth of many cancer cell types by inducing apoptosis. The objective of this study was to determine whether epigallocatechin gallate (EGCG), the primary green tea catechin, could act directly on adipocytes to inhibit adipogenesis and induce apoptosis.


METHODS
Mouse 3T3-L1 preadipocytes and mature adipocytes were used. To test the effect of EGCG on viability, cells were incubated for 3, 6, 12, or 24 hours with 0, 50, 100, or 200 microM EGCG. Viability was quantitated by MTS assay. To determine the effect of EGCG on apoptosis, adipocytes were incubated for 24 hours with 0 to 200 microM EGCG, then stained with annexin V and propidium iodide and analyzed by laser scanning cytometry. Both preadipocytes and adipocytes were also analyzed for apoptosis by terminal deoxynucleotidyl transferase dUTP nick-end labeling assay. To determine the effect of EGCG on adipogenesis, maturing preadipocytes were incubated during the 6-day induction period with 0 to 200 microM EGCG, then stained with Oil-Red-O and analyzed for lipid content.


RESULTS
EGCG had no effect on either viability or apoptosis of preconfluent preadipocytes. EGCG also did not affect viability of mature adipocytes; however, EGCG increased apoptosis in mature adipocytes, as demonstrated by both laser scanning cytometry and terminal deoxynucleotidyl transferase dUTP nick-end labeling assays. Furthermore, EGCG dose-dependently inhibited lipid accumulation in maturing preadipocytes.


CONCLUSIONS
These results demonstrate that EGCG can act directly to inhibit differentiation of preadipocytes and to induce apoptosis of mature adipocytes and, thus, could be an important adjunct in the treatment of obesity.
444 Edgar L. Rhodes Center for Animal and Dairy Science, University of Georgia, Athens, GA 30602-2771, USA.
Ji
J
Lin
Mary Anne
MA
Della-Fera
Clifton A
CA
Baile
D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001391:Azo Compounds / Q000737:chemistry; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects*; D004396:Coloring Agents / Q000737:chemistry; D020287:In Situ Nick-End Labeling; D047569:Laser Scanning Cytometry; D051379:Mice; D013662:Tea
D001391:Azo Compounds; D004396:Coloring Agents; D013662:Tea; D002392:Catechin; C045651:epigallocatechin gallate; C011049:oil red O