Neuroprotective effects of human recombinant interleukin-1 receptor antagonist in focal cerebral ischaemia in the rat

Recombinant human interleukin-l receptor antagonist (rhIL-1ra) markedly protects against focal cerebral ischaemia in the rat, implicating endogenous IL in the events leading to cerebral infarction. The present experiments investigated the effect of intracerebroventricular (i.c.v.) administration of IL-1 beta or rhIL-1ra on ischaemia damage and physiological parameters after permanent middle cerebral artery occlusion in the rat. IL-1 beta (5 ng, i.c.v.) markedly (92%) enhanced infarct volume and caused a significant rise in body temperature, but rhIL-1ra (10 mu g, i.c.v.) significantly reduced infarct volume and did not significantly affect heart rate, blood pressure, or body temperature. rhIL-1ra administered 30 min before, or at the time of ischaemia significantly reduced infarct volume in cortex (55 and 60%, respectively) and striatum (57 and 41%, respectively). rhIL-1ra administered 30 min after ischaemia significantly reduced total and cortical infarct volume (26 and 29%, respectively), but did not significantly protect striatal tissue. The effects of rhIL-1ra were still evident in both cortex and striatum 7 days after ischaemia. These results support the role of IL-1 in ischaemic brain damage, revealing potent, sustained, neuroprotective effects of rhIL-1ra in the cortex and striatum, which cannot be attributed directly to changes in physiological parameters.