Valentino M, Governa M, Marchiseppe I, Visonă I
Institute of Occupational Medicine, University of Ancona, Italy.
Arch Toxicol. 1991;65(8):685-8. doi: 10.1007/BF02098038.
Previous in vitro experiments have shown that lead can inhibit PMN chemotaxis, phagocytosis and superoxide formation. Moreover, we have observed an inhibition of PMN chemotaxis in workers occupationally exposed to lead with a mean blood lead concentration of 3.06 mumol/l. The present study was carried out to evaluate locomotion and luminol assisted chemiluminescence (CL) of polymorphonuclear leukocytes (PMN) harvested from ten lead occupationally exposed workers with blood lead concentrations of 1.59 mumol/l (SD 0.27 mumol/l). Since lipids affect PMN activity and lipid composition is modified in erythrocytes of lead workers, PMN lipids were also studied. Ten healthy male subjects of the same age were taken as controls. Chemotaxis, i.e. locomotion stimulated through a specific membrane receptor, was impaired in the PMN of lead workers, but random migration, i.e. unstimulated cell locomotion, and respiratory burst were both unmodified. Cholesterol and phospholipids were not changed, but the percentage of arachidonic acid was significantly increased. The release of LTB4, generated by the oxidative metabolism of arachidonic acid, was increased. CL, which detects reactive oxygen species (ROS), was unmodified, but this lack of change could be the result of an increase in ROS, due to the augmentated percentage of arachidonic acid, and of a decrease in ROS, due to a direct inhibitory effect of lead on ROS generation. On the basis of the results from these ex vivo experiments, the conclusion that chemotaxis is the PMN function primarily affected by lead was confirmed. PMN are considered to be one of the first cellular targets for the action of lead; low exposure to lead modifies their activity and mainly modifies chemotaxis and LTB4 production.
以往的体外实验表明，铅可抑制中性粒细胞的趋化性、吞噬作用和超氧化物的形成。此外，我们观察到职业性接触铅且平均血铅浓度为3.06μmol/L的工人中性粒细胞趋化性受到抑制。本研究旨在评估从10名职业性接触铅且血铅浓度为1.59μmol/L（标准差0.27μmol/L）的工人中采集的多形核白细胞（PMN）的运动能力和鲁米诺辅助化学发光（CL）。由于脂质会影响PMN活性，且铅作业工人红细胞中的脂质成分会发生改变，因此对PMN脂质也进行了研究。选取10名年龄相同的健康男性作为对照。铅作业工人的PMN中，通过特定膜受体刺激的趋化性（即运动能力）受损，但随机迁移（即未受刺激的细胞运动）和呼吸爆发均未改变。胆固醇和磷脂未发生变化，但花生四烯酸的百分比显著增加。由花生四烯酸氧化代谢产生的白三烯B4（LTB4）的释放增加。检测活性氧（ROS）的CL未改变，但这种无变化可能是由于花生四烯酸百分比增加导致ROS增加，以及铅对ROS生成的直接抑制作用导致ROS减少共同作用的结果。基于这些体外实验的结果，证实了趋化性是主要受铅影响的PMN功能这一结论。PMN被认为是铅作用的首批细胞靶点之一；低水平接触铅会改变其活性，主要改变趋化性和LTB4的产生。
