Are prostaglandins involved in experimental ischemic edema in gerbils?

Sixty-five male gerbils, divided into 3 groups, were used in this study, in which focal brain specific gravity, taken as a measure of edema, was compared to the corresponding focal cerebral blood flow using the hydrogen washout technique. Extracranial unilateral or bilateral carotid ligation was performed and one hour later the animal was sacrificed. When focal blood flow was less than 20 ml/100 g/min, edema developed and increased with progressive ischemia, reaching maximal values at 5-7 ml/100 g/min. In the zero flow situation there was no edema. Pretreatment of the other 2 groups with indomethacin or dexamethasone, did not prevent edema formation at flows of 20-12 ml/200 g/min, but considerably reduced the edema previously noted at low flows (5-7 ml/100 g/min). The drugs did not affect the decreased flow in the ischemic area. We conclude that prostaglandins, released by membrane disruption, are involved in the development of ischemic edema.