Possible involvement of interleukin-1 in ischemic brain edema formation.

To determine the contribution of interleukin 1 (IL-1) on ischemic brain edema formation, the effect of recombinant human interleukin 1 beta (rhIL-1 beta), or zinc protoporphyrin (ZnPP) as an IL-1 blocker, on brain edema was studied in rats. The animals were subjected to 60 min of ischemia in a middle cerebral artery occlusion model. Immediately after reperfusion, rhIL-1 beta at a dose of 10 ng/2 microliters, or ZnPP at doses of 1 and 10 micrograms/2 microliters were topically applied into lateral cerebroventricle. In rhIL-1 beta-treated rats, ischemic brain edema formation was significantly increased in the dorsal and ventral areas of the caudate putamen 24 h after reperfusion, compared to that of vehicle-treated control rats. Furthermore, in ZnPP-treated rats, brain edema was decreased in both caudate-putamen areas. This suggests that IL-1 plays an important role in pathogenesis for post-ischemic brain edema.