ABSTRACT
OBJECTIVE: Epidemiology studies indicate that green tea polyphenols (GTP) perform a protective effect on cardiovascular diseases, but the underlying mechanisms are complex. The present study aimed to investigate the effect of GTP on high-fat diets (HFD) induced-early vascular aging. METHODS: Six-week young adult Wistar rats were fed with standard chow or HFD in the presence and absence of GTP (200 mg/kg body weight) for 18 weeks. In vitro experiment, human umbilical vascular endothelial cells (HUVECs) were treated with palmitic acid (PA) and GTP. RESULTS: The results showed that GTP alleviated the disorganized arterial wall and the increased intima-media thickness induced by HFD. In addition, the vascular oxidative injury was suppressed following GTP treatment. Furthermore, GTP elevated the ratio of LC3-II/LC3-I and suppressed expression of p62/SQSTM1, and restored SIRT3 expression in the aorta of HFD rats. Consistently, in cultured HUVECs, GTP inhibited cell senescence indicated by SA-ß-gal and promoted endothelial autophagy compared with the PA treatment group. The activity of SIRT3 was specifically inhibited by 3-TYP, and the protective effect of GTP was consequently abolished. CONCLUSION: The findings indicated that GTP protected against early vascular senescence in young HFD rats via ameliorating oxidative injury and promoting autophagy which was partially regulated by the SIRT3 pathway.
