Departamento de Bioquímica, Facultad de Medicina, Universidad Juárez del Estado de Durango, Durango, Dgo, Mexico.
Toxicol In Vitro. 2010 Aug;24(5):1338-46. doi: 10.1016/j.tiv.2010.05.002. Epub 2010 May 10.
One important effect of lead toxicity in erythrocytes consists of increasing Ca(2+) which in turn may cause alterations in cell shape and volume and it is associated with cellular rigidity, hemolysis, senescence and apoptosis. In this work, we proposed the use of erythrocytes incubated with Pb(2+) to assess association of the mechanisms of lead erythrocyte oxidative damage and calcium homeostasis. Lead incubation produced an increase in Ca(2+) dose- and time-dependent, which mainly involved Ca(2+) entry mechanism. Additionally, in this in vitro model alterations similar to erythrocytes of lead-exposed workers were produced: Increase in Ca(2+) influx, decrease in (Ca(2+)-Mg(2+))-ATPase activity and GSH/GSGG ratio; increase in lipoperoxidation, protein carbonylation and osmotic fragility accompanied of dramatic morphological changes. Co-incubation with trolox, a soluble vitamin-E analog is able to prevent these alterations indicating that lead damage mechanism is strongly associated with oxidative damage with an intermediate toxic effect via Ca(2+) increase. Furthermore, erythrocytes oxidation induced with a free radical generator (APPH) showed effects in Ca(2+) and oxidative damage similar to those found in erythrocytes incubated with lead. Co-incubation with trolox prevents the oxidative effects induced by AAPH in erythrocytes. These results suggest that increase of Ca(2+) depends on the oxidative status of the erythrocytes incubated with lead. We consider that this model contributes in the understanding of the relation between oxidative damage induced by lead exposure and Ca(2+) homeostasis, the consequences related to these phenomena and the molecular basis of lead toxicity in no excitable cells.
铅毒性对红细胞的一个重要影响是增加Ca(2+)，这反过来可能导致细胞形状和体积的改变，并与细胞刚性、溶血、衰老和凋亡有关。在这项工作中，我们提出使用与 Pb(2+)孵育的红细胞来评估铅对红细胞氧化损伤和钙稳态机制的关联。铅孵育会产生剂量和时间依赖性的Ca(2+)增加，这主要涉及 Ca(2+)内流机制。此外，在这种体外模型中，产生了类似于暴露于铅的工人的红细胞的类似变化：Ca(2+)内流增加，(Ca(2+)-Mg(2+))-ATP 酶活性和 GSH/GSGG 比降低；脂质过氧化、蛋白质羰基化和渗透脆性增加，伴有明显的形态变化。与 Trolox（一种可溶的维生素 E 类似物）共孵育能够预防这些变化，表明铅损伤机制与氧化损伤密切相关，通过Ca(2+)增加具有中间毒性作用。此外，自由基生成剂（APPH）诱导的红细胞氧化作用显示出与在铅孵育的红细胞中发现的相似的Ca(2+)和氧化损伤效应。Trolox 共孵育可防止 AAPH 在红细胞中诱导的氧化作用。这些结果表明，Ca(2+)的增加取决于与铅孵育的红细胞的氧化状态。我们认为，这种模型有助于理解铅暴露诱导的氧化损伤与 Ca(2+)稳态之间的关系，以及这些现象相关的后果和非兴奋细胞中铅毒性的分子基础。
