Linoleic acid, cis-epoxyoctadecenoic acids, and dihydroxyoctadecadienoic acids ale toxic to Sf-21 cells in the absence of albumin

Conversion of 12,13-cis-epoxyoctadecenoic acid (12,13-EOA) to 12,13-dihydroxyoctadecenoic acid (12,13-DHOA) by soluble epoxide hydrolase has been suggested to be a critical step in mediating the toxicity of epoxidized linoleic acid. The current study tests the hypothesis that low levels of albumin in the normal culturing media of Sf-21 cells can protect these cells from exposures to 12,13-EOA, but not 12,13-DHOA. In albumin-free media, Sf-21 cells exposed to 100 muM 12,13-EOA, and 12,13-DHOA for 1 min showed significant signs of mitochondrial dysfunction,which led to cytotoxicity. The addition of bovine serum albumin (BSA) at a concentration (3 muM) found in normal serum-supplemented media protected Sf-21 cells exposed to 12,13-EOA, but not 12,13-DHOA while BSA (500 muM) fully protected Sf-21 cells exposed to these fatty acids. These data resolve previous discrepancies observed among in vitro models and help clarify our understanding of how these metabolites affect human health. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.