To clarify possible roles in the pathogenesis of ischemic
brain edema, identification and quantitative analysis of hydroxy-
eicosatetraenoic acids (HETEs) in rat brains exposed to
middle cerebral artery occlusion were carried out using high-performance liquid chromatography. Rat brain sampling was done by in situ freezing 24 and 72 hours after occlusion. Only a small amount of
15-HETE was found in control rat brains. Twenty-four hours after
ischemia,
11-HETE appeared, and the amount of
15-HETE tended to increase. Seventy-two hours after
ischemia, when
brain edema reached its maximum, 5-, 8-, 9-, 11-, 12-, and 15-HETEs were identified, and the amounts of all HETEs except 8- and
12-HETE were significantly increased. The detection of
5-HETE in ischemic rat brain indicates the simultaneous production of
leukotrienes in the same brain area. The above results support the view that
lipoxygenase products may play significant roles in the formation of ischemic
brain edema.