Cisplatin induces N-acetyl cysteine suppressible F₂ isoprostane production and injury in renal tubular epithehal cells

In the low intracellular chloride milieu, chloride ions of cisplatin may exchange for cellular SH moieties resulting in glutathione depletion, H₂O₂ accumulation, and lipid peroxidation. Cisplatin-induced lipid peroxidation, in addition to causing direct cellular injury, may further contribute to cisplatininduced renal dysfunction by generating vasoconstrictive E₂-and F₂-isoprostanes. The aim of this study was to determine whether cisplatin- induced renal epithelial (LLC-PK₁ and primary human proximal tubular) cell injury is associated with increased production of isoprostanes, and whether this can be suppressed with a thiol donor, N-acetyl cysteine. It was confirmed that incubation of renal epithelial cells with cisplatin resulted in N-acetyl cysteine-inhibitable glutathione depletion, H₂O₂ accumulation, lipid degradation, and lactate dehydroge- nase release. In additional experiments, incubation of cells with cisplatin for 48 h was accompanied by a dose-related increase in total (free plus esterified) F₂-isoprostanes. An increase in F₂-isoprostanes was discernible at 16.5 μM cisplatin and doubled at 66.0 μM. N-Acetyl cysteine at 50 μM concentration effectively suppressed 66.0 μM cisplatin-induced increase in isoprostanes. Similar findings were also obtained in human cells. Thus, cisplatin-induced tubular cell injury is accompanied by increased isoprostane production through a mechanism involving thiol depletion. On the basis of this new finding, it is hypothesized that these arachidonic acid peroxidation products may be partially responsible for the cisplatin-induced renal vasoconstriction demonstrable in the in vivo models.