The expression and source of IL-17 on human cerebral ischemic injury

Objective To confirm whether IL-17 plays a role in the process of human cerebral ischemic injury or not and to determine the source of IL-17 expressing cell during cerebral ischemic injury.Methods The levels of IL-17 in the ischemic hemisphere of human brain,which was removed at necropsy,were assayed immunohistochemically.In rats,permanent middle cerebral artery occlusion (pMCAO) was obtained by inserting nylon monofilament into the right external carotid artery and occluding the right middle cerebral artery.The expression of IL-17 mRNA in rat was assayed using oligoprobe in situ hybridization.IL-17 production by neuroglial cells was assayed by double-staining using antibody glial fibrillary acidic protein (GFAP)and antibody of IL-17.Results Levels of IL-17 were elevated in the ischemic hemispheres of human brain compared with the opposite normal hemispheres and peaked during 3d~5d after brain ischemia.The IL-17-positive cells were found in the ischemic lesion region.IL-17 mRNA was also elevated in ischemic hemispheres of pMCAO-operated rats,which were slightly elevated after 1h and peaked on 6d.IL-17 and GFAP double-stained were extensive in rat ischemic hemisphere. Conclusion The data suggested that IL-17 was mainly involved in the process of local inflammatory reaction of both human and rat ischemic brain injury,and also suggested that in additional to T cells,the neuroglial cell might be another cellular source of IL-17 in progression of cerebral ischemic injury in rats experiment.