F2-isoprostanes are the newly identified
reactive oxygen species-catalyzed peroxidation products of arachidonate. The infusion of these
prostaglandin F2-like prostanaoids into the rat kidney induces profound parallel reductions in RBF and GFR, suggesting that these metabolites may be partly responsible for the hemodynamic alterations seen in
free radical-linked
acute renal injury models. The present study examined directly in renal proximal tubular (LLC-PK1) cells whether
hydrogen peroxide, a
reactive oxygen species implicated in many models of
acute renal injury, induces
F2-isoprostane production and whether its production can be inhibited by the recently synthesized
lipid peroxidation inhibitor 21-aminosteroid (lazaroid U-74389G). The incubation of LLC-PK1 cell layers with
hydrogen peroxide for 3 h resulted in a dose-related six-fold increase in
F2-isoprostane production, measured by the gas chromatographic-mass spectroscopic method. The preincubation of cells with 21-aminosteroid prevented
hydrogen peroxide-induced
F2-isoprostane production, a finding also demonstrable with other lipid peroxidation inhibitors, e.g.,
2-methyl aminochroman (U-83836E) and
diphenyl-
p-phenylenediamine. Besides inhibiting
isoprostane production, 21-aminosteroid reduced
hydrogen peroxide-induced
lipid degradation and peroxidation, and protected the cells against
hydrogen peroxide-induced cytolysis. The novel finding that
hydrogen peroxide induces 21-aminosteroid-inhibitable
F2-isoprostane production in renal epithelial cells supports the in vivo report that its levels are elevated in
reactive oxygen species-linked renal injury models such as
ischemia-reperfusion. Besides direct cell injury, lipid peroxidation by generating
F2-isoprostanes may further contribute to renal dysfunction through a vasoconstrictive mechanism. Thus, the inhibition of excess
F2-isoprostane production may be one of the additional mechanisms, besides cytoprotection, by which
antioxidants ameliorate renal dysfunction in experimental models of
acute renal injury.