McConnell J R, Crockard A D, Cairns A P, Bell A L
Queen's University Musculoskeletal Education and Research Unit, Department of Rheumatology, Musgrave Park Hospital, Belfast, UK.
Clin Exp Rheumatol. 2002 Sep-Oct;20(5):653-60.
(i) To determine the levels of nuclear DNA damage in freshly isolated and cultured neutrophils from SLE patients (SLE), rheumatoid arthritis patients (RA) and healthy individuals and relate these to the percentage of apoptotic neutrophils. (ii) To assess rates of repair of neutrophil oxidative DNA damage.
The comet assay was used to quantify nuclear DNA damage in neutrophils from SLE patients (n = 20), control subjects (n = 15) and RA patients (n = 15). Levels of DNA damage were related to apoptosis as assessed by annexin V binding and morphology. Rates of repair of neutrophil oxidative DNA damage was measured by incorporating formamidopyrimidine-DNA glycosylase (FPG) into the comet assay.
Nuclear DNA damage in freshly isolated and cultured (20 h) neutrophils was significantly greater in SLE patients (median = 12.5%, 27.3%; respectively) compared with RA patients (median = 9.4%, p = 0.002; 19.3%, p = 0.002; respectively) and control subjects (median = 8.2%, p = 0.003; 18.7%, p = 0.01, respectively). Significantly higher levels of circulating apoptotic neutrophils were demonstrated in SLE patients compared to RA and control subjects. Similar findings were observed following 20 h cultured neutrophil preparations. However, no significant direct correlation between neutrophil apoptosis and DNA damage was observed. Neutrophils from 3 of 5 SLE patients demonstrated an impaired ability to repair oxidatively modified DNA.
Neutrophils from SLE patients display increased DNA damage and, additionally, may demonstrate defective repair of oxidative DNA damage. These features, in addition to increased rates of neutrophil apoptosis, may act as contributing factors to autoantigen excess and immune activation.
（i）测定系统性红斑狼疮（SLE）患者、类风湿关节炎（RA）患者及健康个体新鲜分离和培养的中性粒细胞中的核DNA损伤水平，并将其与凋亡中性粒细胞的百分比相关联。（ii）评估中性粒细胞氧化性DNA损伤的修复率。
采用彗星试验对20例SLE患者、15例对照受试者和15例RA患者的中性粒细胞中的核DNA损伤进行定量。通过膜联蛋白V结合和形态学评估，将DNA损伤水平与凋亡相关联。通过在彗星试验中加入甲酰胺嘧啶-DNA糖基化酶（FPG）来测定中性粒细胞氧化性DNA损伤的修复率。
与RA患者（中位数分别为9.4%，p = 0.002；19.3%，p = 0.002）和对照受试者（中位数分别为8.2%，p = 0.003；18.7%，p = 0.01）相比，SLE患者新鲜分离和培养（20小时）的中性粒细胞中的核DNA损伤明显更大（中位数分别为12.5%，27.3%）。与RA和对照受试者相比，SLE患者循环凋亡中性粒细胞水平明显更高。在培养20小时的中性粒细胞制剂中也观察到类似结果。然而，未观察到中性粒细胞凋亡与DNA损伤之间存在显著的直接相关性。5例SLE患者中有3例的中性粒细胞修复氧化修饰DNA的能力受损。
SLE患者的中性粒细胞表现出DNA损伤增加，此外，可能还存在氧化性DNA损伤修复缺陷。除了中性粒细胞凋亡率增加外，这些特征可能是自身抗原过量和免疫激活的促成因素。
