Effect of ischemic preconditioning on edema formation and cerebrovascular injury following focal cerebral ischemia.

Many studies have shown that a brief period of ischemia can protect against a subsequent severe ischemic event and this has been termed ischemic preconditioning (IPC). Most studies have been focused on neuroprotection, with only a little attention on cerebrovascular effects. This study examines the effect of IPC, induced by 15 minutes of middle cerebral artery occlusion (MCAO) in the rat, on brain edema formation and cerebrovascular injury induced by a permanent MCAO induced three days later. Brain edema formation was significantly reduced in IPC treated rats compared to non-IPC treated rats. IPC-treated rats also had reduced blood-brain barrier disruption and reduced cerebrovascular expression of heat shock protein 70, a marker of cell stress. These results indicate that IPC reduces cerebrovascular injury from subsequent permanent focal cerebral ischemia. Understanding the mechanisms involved may provide new therapeutic strategies for stroke.