Dietary
docosahexaenoic acid (DHA) intake can decrease the level of membrane
arachidonic acid (AA), which is liberated during
cerebral ischemia and implicated in the pathogenesis of brain damage. Therefore, in the present study, we investigated the effects of chronic ethyl
docosahexaenoate (E-DHA) administration on mortality and
cerebral edema induced by transient forebrain
ischemia in gerbils. Male Mongolian gerbils were orally pretreated with either E-DHA (100, 150 mg/kg) or vehicle, once a day, for 4 weeks and were subjected to transient forebrain
ischemia by bilateral common carotid occlusion for 30 min. The content of brain
lipid AA at the termination of treatment, the survival ratio, change of regional cerebral blood flow (rCBF), brain free AA level,
thromboxane B(2) (TXB(2)) production and
cerebral edema formation following
ischemia and reperfusion were evaluated. E-DHA (150 mg/kg) pretreatment significantly increased survival ratio, prevented post-ischemic hypoperfusion and attenuated
cerebral edema after reperfusion compared with vehicle, which was well associated with the reduced levels of AA and TXB(2) in the E-DHA treated brain. These data suggest that the effects of E-DHA pretreatment on ischemic mortality and
cerebral edema could be due to reduction of free AA liberation and accumulation, and its metabolite synthesis after
ischemia and reperfusion by decreasing the content of membrane AA.