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Direct Measurement of Lipid Hydroperoxides in Iron‐Dependent Spinal Neuronal Injury
Author(s) -
Zhang JueRong,
Scherch Heidi M.,
Hall Edward D.
Publication year - 1996
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1996.66010355.x
Subject(s) - chemistry , lipid peroxidation , phosphatidylethanolamine , neuroprotection , biochemistry , antioxidant , ferrous , phosphatidylcholine , lipid peroxide , phospholipid , pharmacology , biology , membrane , organic chemistry
The relationship between iron‐dependent fetal mouse spinal cord neuron injury and the generation of endogenous lipid hydroperoxides (LOOHs) has been investigated. Cultured spinal cord neurons were incubated with ferrous iron (3–200 µ M ). Cell viability was measured in terms of the uptake of α‐[ methyl ‐ 3 H]aminoisobutyric acid ([ 3 H]AIB). Both endogenously and iron‐generated LOOH, i.e., free fatty acid hydroperoxide (FFAOOH), phosphatidylethanolamine hydroperoxide (PEOOH), and phosphatidylcholine hydroperoxide (PCOOH), were measured directly by an HPLC‐chemiluminescence (HPLC‐CL) assay. The FFAOOH, PEOOH, and PCOOH levels in neurons incubated with 200 µ M Fe 2+ for 40 min were, respectively, 22‐, 158‐, and sevenfold higher than those in non‐iron‐exposed cultures, demonstrating that phosphatidylethanolamine (PE) was most sensitive to peroxidation. The dose‐response and time course of Fe 2+ ‐induced generation of these LOOHs were also established. In both experiments, the LOOH levels were correlated directly with loss of neuronal viability, suggesting strongly a direct relationship between lipid peroxidation and cell injury. On examination of the time course of the LOOH generation, an immediate increase in PEOOH and PCOOH levels with only 30 s of Fe 2+ incubation was observed. In contrast, a lag phase in the increase in FFAOOH level (2 min after Fe 2+ addition) suggested a delay in the activation of phospholipase A 2 (PLA 2 ) required for the hydrolysis and generation of FFAOOH. This culture system provides an excellent model for screening antioxidant neuroprotective compounds with regard to their ability to protect against iron‐dependent peroxidative injury and the relationship of the neuroprotection to inhibition of lipid peroxidation and/or PLA 2 .