Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil.
Life Sci. 2013 Sep 17;93(9-11):416-22. doi: 10.1016/j.lfs.2013.07.012. Epub 2013 Jul 19.
The relationship between the activity of eosinophils and platelets has been observed in recent decades by many scientists. These observations include increased numbers of eosinophils associated with platelet disorders, including changes in the coagulation cascade and platelet aggregation. Based on these observations, the interaction between eosinophils and platelets in platelet aggregation was analyze.
Human platelets were incubated with eosinophil cytosolic fraction, promyelocytic human HL-60 clone 15 cell lineage, and eosinophil cationic protein (ECP). Platelet rich plasma (PRP) aggregation was induced by adenosine diphosphate, platelet activating factor, arachidonic acid, and collagen, and washed platelets (WP) were activated by thrombin.
Aggregation induced by all agonists was dose dependently inhibited by eosinophil cytosolic fraction. This inhibition was only partially reversed by previous incubation of the eosinophils with l-Nitro-Arginine-Methyl-Ester (l-NAME). Previous incubation with indomethacin did not prevent the cytosolic fraction induced inhibition. The separation of eosinophil cytosolic fraction by gel filtration on Sephadex G-75 showed that the inhibitory activity was concentrated in the lower molecular weight fraction. HL-60 clone 15 cells differentiated into eosinophils for 5 and 7 day were able to inhibit platelet aggregation. The ECP protein inhibited the platelet aggregation on PRP and WP. This inhibition was more evident in WP, and the citotoxicity MTT assay proved the viability of tested platelets, showing that the observed inhibition by the ECP protein does not occur simply by cell death.
Our results indicate that eosinophils play a fundamental role in platelet aggregation inhibition.
近几十年来，许多科学家观察到了嗜酸性粒细胞与血小板之间的活性关系。这些观察结果包括与血小板紊乱相关的嗜酸性粒细胞数量增加，包括凝血级联和血小板聚集的变化。基于这些观察结果，分析了嗜酸性粒细胞与血小板在血小板聚集中的相互作用。
将人血小板与嗜酸性粒细胞胞质部分、早幼粒细胞人 HL-60 克隆 15 细胞系和嗜酸性粒细胞阳离子蛋白（ECP）孵育。用二磷酸腺苷、血小板激活因子、花生四烯酸和胶原蛋白诱导富含血小板的血浆（PRP）聚集，用凝血酶激活血小板。
所有激动剂诱导的聚集均被嗜酸性粒细胞胞质部分剂量依赖性抑制。这种抑制作用仅部分被先前用 l-Nitro-Arginine-Methyl-Ester（l-NAME）孵育的嗜酸性粒细胞逆转。先前用吲哚美辛孵育并不能阻止胞质部分诱导的抑制作用。用 Sephadex G-75 凝胶过滤分离嗜酸性粒细胞胞质部分显示，抑制活性集中在低分子量部分。分化为嗜酸性粒细胞 5 天和 7 天的 HL-60 克隆 15 细胞能够抑制血小板聚集。ECP 蛋白抑制 PRP 和 WP 中的血小板聚集。在 WP 中这种抑制更为明显，MTT 细胞活力测定证明了受测血小板的活力，表明观察到的 ECP 蛋白抑制作用不是简单地通过细胞死亡发生的。
我们的结果表明，嗜酸性粒细胞在血小板聚集抑制中起着重要作用。
