Enhanced free radical scavenging and decreased lipid peroxidation in the rat fetal brain after treatment with ethyl docosahexaenoate

In order to explore possible mechanisms to explain previously observed decr eases in fetal brain lipid peroxidation (LPO) following intraamniotic admin istration of ethyl docosahexaenoate (Et-DHA) to near term fetuses, the hydr oxyl radical trapping capacity of Et-DHA treated fetal brain preparations w as compared to control ethyl oleate injected fetuses by electron spin reson ance using 5,5'-dimethyl-1-pyrroline N-oxide (DMPO) probe. Lipid extracts f rom control brains showed little hydroxyl radical scavenging activity, wher eas those from the Et-DHA injected animals exhibited an almost 70% decrease in the amount of DMPO-OH adducts. A marked decrease (58%) in LPO formation was noticed in the Et-DHA treated animals compared to controls. The Et-DHA treatment related trapping capacity resided in the phospholipid fraction o f the lipid extract, which was enriched in both docosahexaenoic acid and am inophospholipid contents. The decreased LPO production, as well as increase d production of prostaglandin E-2 and nitric oxide by the fetal brain follo wing Et-DHA administration, could be mimicked by a synthetic quinone posses sing both hydroxyl radical producing and LPO propagation inhibiting propert ies. The data are consistent with the possibility that the neuroprotective effect of Et-DHA might be due to possible free radical scavenging ability o f the brain tissue and interference with LPO propagation. (C) 2001 Elsevier Science B.V. All rights reserved.