Effect of dexamethasone, indomethacin, ibuprofen, and probenecid on carrageenan-induced brain inflammation

✓ A model of brain inflammation has recently been developed in mice using intraventricular injection of carrageenan (CAR). This model is characterized by increased brain water and vascular permeability, by neutrophil extravasation, and by evidence of increased pro-inflammatory arachidonic acid metabolites. The purpose of the current experiments was to determine the mechanism(s) by which CAR induces brain inflammation and to determine the utility of the CAR model in testing systemically administered therapeutic agents for their capacity to inhibit brain inflammation. Dexamethasone inhibited the increased brain water but not the increased vascular permeability produced by CAR. Indomethacin, an inhibitor of prostaglandin formation, suppressed peripheral inflammation produced by local injection of CAR but not brain inflammation produced by intraventricular CAR injection. Subsequent studies with carbon-14-labeled indomethacin showed that indomethacin penetrates peripheral tissues but is excluded from normal br...