左旋精氨酸对急性心肌缺血大鼠L-及P-选择素表达的影响

目的：探讨NO的前体左旋精氨酸（L-arg)对急性心肌缺血（AMI）大鼠心血肌有无保护作用及其作用机制，方法：采用垂体后叶素（Pit)性急性心肌缺血模型，建立正常对照组，阳性对照组，及L－arg治疗组，观察中性粒细胞（PMN）表面L－选择素及心肌微血管内皮细胞表面P－选择素的表达，并测定心肌梗死面积，PMN浸润数及血浆NO，MDA的浓度，结果：阳性对照组与正常对照组相比，其L－选择素及P－选择素表达上调，心肌PMN浸润数，血浆MDA的浓度明显升高，血浆NO的浓度降低，L－arg治疗组上述指标改变的程度明显轻于阳性对照组（P＜0．01），心肌梗死范围小于阳性对照组，结论：外源性L－arg对急性心肌缺血有防治意义，其作用的机制与NO抑制选择素的表达有关。

Effect of L-arginine on expression of L-and P-Selectins in rats with acute myocardial ischemia

Objective: To study the protective effect of NO precursor L arginine (L arg) on myocardium in rats with acute myocardial ischemia and its mechanism. Methods:A rat model of acute myocardial ischemia induced by pituitrin (Pit) was applied. 30 Wistar rats were divided into three groups : normal control group (injected with saline),positive control group (injected with 30 u/kg of Pit),and L arg treatment group (Pit injection followed by L arg injection). The expressions of L selectin on neutrophils and P selectin on myocardial microvascular endotheliocytes were determined. The myocardial infarct area,number of neutrophil infiltration and the levels of NO and MDA in plasma were determined. Results: In the positive control group (Pit group),the expressions of L and P selectin,the number of neutrophil infiltration and the serum MDA increased,while the serum NO level decreased when compared with the normal control group. In the L arg treatment group,the changes of these indicators were significantly lesser than those in the Pit group ( P <0.01),and the infarct area was smaller as well. Conclusion: The results suggested that L arg exerted significant cardioprotective effects in acute myocardial ischemia,and there was a positive correlation between the cardioprotection of L arg and the inhibition of NO on selectins expression.