Green Tea Polyphenols Alleviate Autophagy Inhibition Induced by High Glucose in Endothelial Cells
The effects of green tea polyphenols on autophagy inhibition induced by high glucose.
Bovine aortic endothelial cells (BAECs) were cultured with high glucose (33 mmol/L), 4 mg/L green tea polyphenols (GTPs) or 4 mg/L GTPs co-treatment with high glucose for 24 h in the presence or absence of Bafilomycin-A1 (BAF). We observed that high glucose increased the accumulation of LC3-II. Treatment with BAF did not further increase the accumulation of LC3-II. Results also showed an increased level of p62 and decreased Beclin-1. However, GTPs showed inversed trends of those proteins. Furthermore, GTPs co-treatment with high glucose decreased the level of LC3-II and a much higher accumulation of LC3-II was observed in the presence of BAF in comparison with high glucose alone. Results also showed a decreased p62 and increased Beclin-1. The results demonstrated that GTPs alleviated autophagy inhibition induced by high glucose, which may be involved in the endothelial protective effects of green tea against hyperglycemia.
GTPs promote autophagy while high glucose blocks the degradation of autophagy and GTPs alleviate high glucose induced inhibition of autophagy. One limitation of this study is that the autophagic flux was determined in cells. Whether our conclusion holds true requires further investigation using diabetic animal models. Although we still lack the data about the relationship between GTPs and diabetes cardiovascular complications, our results indicated that GTPs might still be a promising approach for prevention diabetes cardiovascular complications.