心肌缺血预处理的抗血小板活化和内皮保护作用的实验研究

目的探讨心肌缺血预处理（MIP）对缺血-再灌注期血小板活化和血管内皮细胞功能的影响。方法将45只成年新西兰大白兔随机分为对照组（23只）和MIP组（25只），分别在试验的不同时间段行血细胞计数，并测定血浆可溶性P-选择素、血栓烷B2（TXB2）和6-酮-前列腺素F1α（6-keto—PGF1α）的含量。同时行心脏血管内皮细胞P-选择素表达的免疫组化分析。结果（1）两组实验动物的白细胞计数在再灌注期均明显升高（P〈0．05），MIP组缺血前的计数值也升高，但在再灌注期同一时间点均明显低于对照组（P〈0．05）。（2）较之基础状态时，MIP组再灌注60、120min时可溶性P-选择素明显升高、6-Keto—PGF1α明显下降（均P〈0．05），而且整个再灌注期TXB。水平均明显高于基础状态（P〈0．05）；对照组自缺血40min起，可溶性P-选择素及。rX82水平均明显升高、6-Keto—PGF1α明显下降（均P〈0.05）。与对照组同一时间点比较，MIP组再灌注120min的可溶性P-选择素以及缺血后的TXB。水平均明显降低、再灌注60、120min的6-Keto—PGF1α明显升高（均P〈0.05）。结论MIP可以有效抑制缺血-再灌注期血小板活化，从而保护病变区域血管内皮细胞功能。

Myocardial ischemic preconditioning in inhibiting platelet activation and preventing endothelial injury during ischemia-reperfusion

Objective To evaluate the effects of myocardial ischemic preconditioning （MIP）on platelet activation and endothelial function changes during ischemia-reperfusion （I/R）. Methods Forty New Zealand white rabbits were divided into control group and MIP group randomly. Plasma soluble P-selectin （sP-selectin）, thromboxane B2 （TXB2）, 6-keto-PGF1α were measured and blood cell counts were examined at different time points. P-selectin IH was detected in heart specimens. Results Blood white cells increased in all animals during I/R （MIP group also increased at pre-occlusion）, but compared with control group, MIP group had lower blood cell counts. MIP group had higher sP-selectin level at reperfusion 60min and 120min, lower 6-keto-PGF1α level at the same time; and higher TXB2 level in all the reperfusion times. Control group had higher sP-selectin, TXB2, but lower 6-keto-PGF1α level from reperfusion 40min during the reperfusion periods. Compared with control group, MIP group showed lower TXB2 level after the coronary artery occlusion, lower sP-selectin level at reperfusion 120min, and higher 6-keto-PGF1α level at reperfusion 60min and 120min. Conclusion MIP can effectively inhibit platelet activation and protect endothelial function during the I/R periods.