GLIAL CELLSExpression of IL-6 in the ischemic penumbraBlock, F1,2; Peters, M1; Nolden-Koch, M1Author Information 1Department of Neurology RWTH Aachen, Pauwelsstr. 30, D-52057 Aachen, Germany 2Corresponding Author: F. Block Acknowledgements: This study was supported by the START-Programme of the Medical Faculty of the RWTH Aachen. Received 7 December 1999; accepted 21 January 2000 NeuroReport: April 7, 2000 - Volume 11 - Issue 5 - p 963-967 Buy Abstract We examined the expression of IL-6 within the ischemic penumbra at various time points after transient (3 h) middle cerebral occlusion (MCA-O) in rats. The animals were killed at 1, 3, 7 or 14 days following operation. Coronal brain sections were processed for immunohistochemistry with antibodies against GFAP, OX 42, IL-6 and Nissl-staining. Glial activation within the penumbra started on day one after ischemia and persisted up to day 14. Expression of IL-6 was not present in sham-operated controls. One day after MCA-O there were several IL-6-positive cells in the penumbra. This expression of IL-6 increased on day 3 and remained elevated up to day 14. According to the shape of the IL-6-positive cells they seem to be microglia and neurons. The present results demonstrate a longlasting expression of IL-6 in the ischemic penumbra. © 2000 Lippincott Williams & Wilkins, Inc.