绿茶及其有效成分对肾性高血压大鼠左心室肥厚的抑制作用

Effects of Green Tea and Tea Extracts on Left Ventricle Hypertrophy Induced by Renovascular Hypertension in Rats

目的研究绿茶及其有效成分对肾性高血压大鼠左心室肥厚的抑制作用。方法雄性Wistar大鼠160只,体重180～220g,随机分为5组,建立二肾一夹法大鼠肾性高血压左心室肥厚模型。假手术组(Sham),正常饮水;阳性对照组(二肾一夹法,2K1C),正常饮水;绿茶组(二肾一夹法加绿茶水,2K1C+GT),饮用2%绿茶水;茶多酚组(二肾一夹法加茶多酚水,2K1C+TP),饮用0.1%茶多酚水;表没食子儿茶素没食子酸酯(EGCG)组(二肾一夹法加EGCG水,2K1C+EGCG),饮用0.05% EGCG水,术后即给予不同浓度的绿茶及其提有效成分,持续8周。分别于实验第0、4、8周测量血压。8周后处死测量左心室与体重比值(LVW/BW)和左心室壁厚度(LVWT),检测胚胎基因-心房利钠肽(embryonic gene atria natriuretic peptide,ANP),并对部分心肌组织HE染色进行病理组织学观察。结果与假手术组比较,阳性对照组和各饮茶组血压、LVW/BW和LVWT均显著升高(P<0.01)。而与阳性对照组相比,不同浓度的绿茶及其有效成分(2%绿茶、0.1%茶多酚、0.05% EGCG)LVW/BW和LVWT显著降低,ANP表达降低,肾性高血压左心室肥厚的组织病理学症状明显改善,但对大鼠收缩压无显著性影响。结论在本实验条件下,绿茶及其有效成分对肾性高血压大鼠左心室肥厚有抑制作用。

Objective To investigate the preventive effects and the molecular mechanisms of green tea and tea extracts （polyphenols and EGCG） on left ventricle hypertrophy （LVH） induced by renovascular hypertension in rats. Method One hundred and sixty male Wistar rats were randomly divided into five groups： negative control group （Sham）, positive control group （2K1C）, green tea group （2KIC ＋ GT）, tea polyphenol group （2KIC ＋ TP）, EGCG group （2K1C ＋ EC, CG）. After surgery operation, rats in different groups received tap water, tap water, 2% green tea, 0.1% tea polyphenol and 0.05% EC, CG, respectively, for 8 weeks. Then blood pressures were measured in the 0, 4th, 8th week, respectively, and the ratio of left ventricle weight to body weight （LVW/BW）, the left ventricular wall thicknesses （LVWT） and embryonic gene atria natriuretic peptide （ANP） protein expressions were detected, and pathological changes of myocardial organizations were observed after HE staining. Results The results showed that the blood pressure, LVW/BW and LVWT in 2K1C group and tea-treatment groups significantly increased （P 〈 0.01 ） compared to those in Sham operation group. However, compared to these parameters in positive control group, the ratio of LVW/BW and LVWT in green tea group, tea polyphenols group and EGCG group significantly decreased （ P 〈 0.05）. ANP protein expressions in tea-treatment groups were also decreased. And obvious pathological changes induced by chronic 2K1C were markedly inhibited by long-term treatment of green tea and tea extracts. There was no significant impact on systolic blood pressure. Conclusion Green tea, tea polyphenols and EGCG could attenuate the development of left ventricular hypertrophy induced by renal hypertension in rats.