title: Hydrogen peroxide induces 21-aminosteroid-inhibitable F2-isoprostane production and cytolysis in renal tubular epithelial cells.
abstract: 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.
authors.affiliation: Department of Medicine, University of Mississippi Medical Center, Jackson 39216-4505, USA.
authors.forename: A
authors.initials: A
authors.lastname: Salahudeen
authors.forename: K
authors.initials: K
authors.lastname: Badr
authors.forename: J
authors.initials: J
authors.lastname: Morrow
authors.forename: J
authors.initials: J
authors.lastname: Roberts
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D015237:Dinoprost / Q000031:analogs & derivatives* / Q000096:biosynthesis; D004847:Epithelial Cells; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D028441:F2-Isoprostanes; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D018374:LLC-PK1 Cells; D050356:Lipid Metabolism; D008054:Lipid Peroxides / Q000378:metabolism; D011281:Pregnatrienes / Q000494:pharmacology*; D013552:Swine
chemical_list: D000975:Antioxidants; D028441:F2-Isoprostanes; D008054:Lipid Peroxides; D011281:Pregnatrienes; C074965:U 74389F; C075750:8-epi-prostaglandin F2alpha; D015237:Dinoprost; D006861:Hydrogen Peroxide