绿茶多酚减轻环孢素A致血管收缩和肾毒性的实验研究

目的探讨绿茶多酚（GTP）对环孢素A（CsA）大鼠胸主动脉环血管舒张功能和肾毒性的作用机制。方法将30只SD大鼠随机平均分为3组：CsA组、对照组和CsA＋GTP组。建立CsA动物模型5周后，检测血尿素氮（BUN）、肌酐（Cr）；取胸主动脉环，观察乙酰胆碱（Ach）诱发的血管舒张反应、L—NAME和吲哚美辛预处理对舒张功能的影响，检测血管组织一氧化氦（NO）水平；并观察各组肾脏组织病理学变化。结果5周后，CsA组大鼠BUN、Cr水平高于对照组和CsA＋GTP组，差异有统计学意义（P〈0．05）。CsA组大鼠Ach引起的胸主动脉环的最大舒张度为（42.5±4．3）％，低于对照组的（81．2±76）％和CsA＋GTP组的（70．1±6．5）％，差异均有统计学意义（P〈0.05）。经L—NAME预处理后，CsA组和CsA＋GTP组动脉环的舒张反应低于对照组；经吲哚美辛预处理后对照组和CsA＋GTP组的舒张反应高于CsA组（均P〈0．05）。CsA组大鼠血管组织中NO含量显著低于对照组和CsA＋GTP组（P〈0．05）。肾脏组织病理学检测：CsA组肾小管、间质损伤评分显著高于对照组，而GTP＋CsA组则显著低于CsA组（均P〈0.05）。结论CsA可对肾脏的结构和功能产生损害，并引起NO介导的内皮依赖性血管舒张功能异常。绿茶多酚能保护肾脏的结构和功能，改善内皮细胞依赖性的血管舒张功能。

I Green tea polyphenols attenuate vasocontraction and nephrotoxicity induced by cyclosporine A

Objective To investigate effects of green tea polyphenols （GTP） on cyclosporine A （CsA）-induced vasocontration and nephrotoxicity. Methods Thirty SD rats were randomly divided into three groups： CsA group, control group and CsA＋GTP group. Five weeks after the treatment, the renal function （BUN, Cre） of the rats were measured. Then thoracic aorta rings were mounted on a bath system, and the Ach induced vasorelaxation, with the effect of L-NAME, indomethacin on the vasorelaxation were evaluated. The contents of nitric oxide （NO） in the vascular tissues were measured. And the histopathology of the kidneys were evaluated. Results In CsA group, the levels of BUN and Cre increased significantly （P〈0.05）. The maximal response for Ach induced vasorelaxation in CsA group was （42.5 ±4.3）%, lower than （81.2± 7.6）% in control group and （70.1± 6.5）% in CsA＋GTP group （P〈0.05）. Pretreatment with L-NAME, the vasorelaxation in CsA group and in CsA＋GTP was lower than that in control group; pretreatment with indomethacin, the vasorelaxation in control group and in CsA＋GTP group was higher than that in GsA group （P〈0.05）. In CsA group, the content of NO in vascular tissues was lower than that in control group and in CsA＋GTP group （P〈0.05）. Histopathology demonstrated that scores of renal tubule and interstitial damages of the kidneys in CsA group was significantly higher than those in other two groups （P〈0.05）. Conclusion CsA can damage the structure and function of kidney, and decrease endothelium-dependent vasorelaxation which is mediated by NO. The administration of GTP attenuate damage of kidney structure and function, and improve the endothelium- dependent vasorelaxation function.