| 摘要: | Forkhead box class O (FoxO)家族基因包含有FoxO1、FoxO3、FoxO4和FoxO6四種，過去有許多文獻分別指出各FoxO基因在細胞內調控了包括分化、葡萄醣代謝、DNA修復和細胞凋亡在內的許多功能。在本實驗中我們使用了3T3-L1前脂肪細胞分化為脂肪細胞的系統，透過處理Dexamethasone、Insulin和3-isobutyl-1-methylxanthine等3種藥物所組成之分化劑，促使細胞進行為期14天的分化。在分化的過程中，細胞的數目有明顯的增加，而細胞內會有三酸甘油脂的堆積。在我們的實驗中發現，相較於沒有處理EGCG的組別，在分化期間處理EGCG會使細胞內油滴的數量減少。當沒有處理EGCG時，細胞的FoxO1、FoxO3、FoxO4和FoxO6的mRNA表現量在分化過程的第2~6天之間會有增加的趨勢，而在第6~14天之間的表現量則會有降低的趨勢。在14天的分化期間，EGCG會大幅降低FoxO1、FoxO3、FoxO4和FoxO6的mRNA表現量。此外ATF-3的mRNA表現量則會有增加的趨勢，其表現量並不會受到EGCG的影響。這些實驗結果顯示EGCG會透過調節FoxO的表現量去影響3T3-L1前脂肪細胞的分化。
;The forkhead box class O (FoxO) family of mammals contained 4 members: FoxO1, FoxO3, FoxO4 and FoxO6. Previous studies have revealed that FoxO genes regulate many functions in cells, including differentiation, glucose metabolism, DNA repair and apoptosis. In this study, we used the preadipocyte-adipocyte differentiation system of 3T3-L1 cells, induced by dexamethasone, insulin and 3-isobutyl-1-methylxanthine for a period of 14 days. During the differentiation, the cell number increased, and the TG droplet increased in cells. Our study also found that the TG droplet decreased when 3T3-L1 cells were treated EGCG, compared to control. In the absence of EGCG, FoxO1, FoxO3, FoxO4, and FoxO6 tended to increase their mRNA expressions from Day 2 to Day 6 of differentiation and decrease from Day 6 to Day 14 of differentiation. EGCG, at 100 μM, but not at 25 or 50 μM, significantly decreased levels of FoxO1, FoxO3, FoxO4, and FoxO6 mRNAs during a 14-day period of differentiation. Moreover, activating transcription factor (ATF)-3 tended to increase its mRNA expression and was not altered by EGCG treatment. These data suggest that EGCG regulates 3T3-L1 adipocyte differentiation through modulations of FoxO but not ATF-3 levels. |
