[Molecular mechanism by which green tea and tea extract inhibits left ventricle hypertrophy induced by renovascular hypertension in rats].

OBJECTIVE: To investigate the preventive effects and the molecular mechanism of tea and tea extracts (polyphenols and EGCG) on left ventricle hypertrophy (LVH) induced by Renovascular hypertension in rats. METHODS: One hundred and sixty male Wistar rats were randomly divided into five groups: negative control group (SHAM), operation group (2K1C), green tea group (2K1C + GT), tea polyphenol group (2K1C + TP), EGCG group (2K1C + EGCG). After surgery operation, rats in different groups received tap water, tap water, 2% green tea, 0.1% tea polyphenol and 0.05% EGCG respectively, as the sole drinking source for 8 weeks until the end of the experiment. RESULTS: The results showed that the blood pressure, the ratio of left ventricle weight to body weight (LVW/BW) and the left ventricular wall thicknesses (LVWT) in 2K1C group significantly increased (P < 0.01), when compared to those in sham operation group. However, when compared to these parameters in operation group, the ratio of LVW/BW and HW/BW in green tea group, tea polyphenols group and EGCG group significantly decreased (P < 0.05), while the activities of GSH-Px and SOD increased, and the levels of ROS in heart were also significantly decreased (P < 0.05). Ras, P-ERK protein expressions in tea-treatment groups were also decreased. CONCLUSION: Green tea, tea polyphenols and EGCG can attenuate the development of left ventricular hypertrophy induced by renal hypertension in rats. The possible mechanisms may be due to its antioxidant properties and the modulation of Ras-to-MAPKs mediated signal transduction.