Middle cerebral artery occlusion in the rat causes a biphasic production of immunoreactive interleukin-1β in the cerebral cortex

Interleukin-1 beta (IL-1 beta) has been implicated in the sequence of events leading to neuronal cell death. We have used an ultrasensitive, highly specific immunometric assay for rat IL-1 beta to determine the pattern of protein expression in the rat cerebral cortex following middle cerebral artery occlusion. In the ipsilateral cerebral cortex there was a biphasic pattern of production with a rapid early phase of IL-1 beta expression followed by a delayed phase at 4 h which was sustained for up to 72 h. There was a similar but smaller expression of 1L-1 beta in the contralateral cortex. Sham operated animals showed no IL-1 beta expression. These results provide further evidence to show that IL-1 beta is expressed in the rat cerebral cortex following cerebral ischaemia. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.