茶多酚对心肌缺血再灌注大鼠左心功能和血清一氧化氮及血浆内皮素的影响

目的：观察茶多酚对心肌缺血再灌注大鼠左心功能和血清一氧化氮（NO）及血浆内皮素（ET）的影响。方法：采用结扎大鼠左冠状动脉前隆支30min后再灌注30min建立在体大鼠心肌缺血再灌注损伤模型，用心功能分析系统测定左室心功能，用酶法测定血清NO水平，用放免法测定血浆ET水平。实验分假手组，心肌缺血再灌注损伤组和茶多酚（40mg.Kg^-1)治疗组。结果：在缺血期和再灌注期，缺血再灌注组与假手术组比，左室LVSP、 dp/dt.max,-dp/dt.max, dp/dt.max/IP明显下降（P＜0．01），血清NO水平明显降低，血浆ET水平显著升高（P＜0．01）；而茶多酚能够明显改善缺血再灌注损伤大鼠左心LVSP，＋dp/dt.max,-dp/dt.max, dp/dt.max/IP，提高血清NO，降低血浆ET，恢复NO／ET平衡（P＜0．01）。结论：茶多酚能改善心肌缺血再灌注损伤大鼠左心舒缩功能，提高血清NO和降低血浆ET，恢复NO／ET平衡。

Effects of Tea Polyphenol on the Left Cardiac Function,the Serum Level of Nitric Oxide and the Plasma Level of Endothelin during Myocardial Ischemia Reperfusion Injury in Rats

Objective To study the effects of tea polyphenols(TP) on the left cardiac function,the serum level of nitric oxide(NO) and the plasma level of endothelein(ET) during myocardial ischemic reperfusion injury(IRI) in rats.Methods The experiment was carried out with IRI of rats in vivo.The left cardiac function was measured by the analysis system,the level of NO in serum by spectrophoto metry and the level of ET in plasma by radioimmunoassay(RIA).The experiment was divided into three groups:sham,ischemia/reperfusion(I/R) and TP group.Results Compared with sham group,in I/R group the left cardiac function was decreased,the level of NO and ratio of NO/ET in serum were decreased,while the content of ET in plasma was increased after IRI(P<0.001).Compared with I/R group,in TP group the left cardiac function was improved,the level of NO in serum was increased obviously while the content of ET in plasma was decreased markedly and the ratio of NO/ET was improved(P<0.001).Conclusion TP can improved left cardiac function and enhanced the level of NO in serum,decreased the content of ET in plasma after myocardial IRI.One of the mechanism on protection of pretreatment with TP may be that it can enhance NOS secretes and protect myocardial and endothelia cells, rehabilitate the situation between NO and ET.