Dias-Da-Motta P, Arruda V R, Muscará M N, Saad S T, De Nucci G, Costa F F, Condino-Neto A
Department of Paediatrics, Faculty of Medical Sciences, State University of Campinas, Brazil.
Br J Haematol. 1996 May;93(2):333-40. doi: 10.1046/j.1365-2141.1996.4951036.x.
The aim of this work was to investigate the release of nitric oxide and superoxide by neutrophils and mononuclear cells from patients with sickle cell anaemia. Nitric oxide release was assayed by the ability of leucocytes to inhibit thrombin-induced washed platelet aggregation. Superoxide release was assessed by a cytochrome c reduction assay. Neutrophils from sickle cell anaemia patients released nitric oxide in a similar manner to those from healthy controls, because inhibition of platelet aggregation by neutrophils from sickle cell anaemia or from healthy controls was blocked by the inhibitor of nitric oxide synthesis N(omega)-nitro-L-arginine methyl ester (300 microM), but not by N(omega)-nitro-D-arginine methyl ester (300 microM) and was reversed by L-arginine (1 mM). Additionally, a similar number of neutrophils from sickle cell anaemia patients and from healthy controls was required to inhibit platelet aggregation. Mononuclear cells from sickle cell anaemia patients inhibited platelet aggregation only in the presence of superoxide dismutase (60 U ml(-1)). Phorbol 12-myristate 13-acetate (PMA, 30 nM)- or zymosan (100 particles/cell)-induced release of superoxide by mononuclear cells from sickle cell anaemia patients was significantly higher than that observed in mononuclear cells from healthy controls (P<0.001 and P<0.01 respectively, Mann-Whitney test). The levels of superoxide released by neutrophils from sickle cell anaemia patients were similar to those from healthy controls. We conclude that mononuclear cells from sickle cell anaemia patients release more superoxide than those from healthy controls, when stimulated with PMA or zymosan in vitro. Considering that superoxide inactivates nitric oxide, that nitric oxide is an important endogenous vasodilator, and that superoxide produces oxidant damage, this greater production of superoxide by mononuclear cells from sickle cell anaemia patients may represent an additional risk factor for the obstruction of the microcirculation and tissue damage in these patients.
这项工作的目的是研究镰状细胞贫血患者的中性粒细胞和单核细胞释放一氧化氮和超氧化物的情况。通过白细胞抑制凝血酶诱导的洗涤血小板聚集的能力来测定一氧化氮的释放。通过细胞色素c还原试验评估超氧化物的释放。镰状细胞贫血患者的中性粒细胞释放一氧化氮的方式与健康对照者相似，因为镰状细胞贫血患者或健康对照者的中性粒细胞对血小板聚集的抑制作用被一氧化氮合成抑制剂N（ω）-硝基-L-精氨酸甲酯（300 μM）阻断，但不被N（ω）-硝基-D-精氨酸甲酯（300 μM）阻断，且可被L-精氨酸（1 mM）逆转。此外，镰状细胞贫血患者和健康对照者需要相似数量的中性粒细胞来抑制血小板聚集。镰状细胞贫血患者的单核细胞仅在存在超氧化物歧化酶（60 U/ml）时才抑制血小板聚集。佛波醇12-肉豆蔻酸酯13-乙酸酯（PMA，30 nM）或酵母聚糖（100个颗粒/细胞）诱导的镰状细胞贫血患者单核细胞释放超氧化物的量显著高于健康对照者的单核细胞（分别为P<0.001和P<0.01，曼-惠特尼检验）。镰状细胞贫血患者的中性粒细胞释放的超氧化物水平与健康对照者相似。我们得出结论，在体外受到PMA或酵母聚糖刺激时，镰状细胞贫血患者的单核细胞比健康对照者释放更多的超氧化物。鉴于超氧化物会使一氧化氮失活，一氧化氮是一种重要的内源性血管舒张剂，且超氧化物会产生氧化损伤，镰状细胞贫血患者单核细胞产生更多的超氧化物可能是这些患者微循环阻塞和组织损伤的另一个危险因素。
