Reduction of ischemic brain injury by topical application of insulin-like growth factor-I after transient middle cerebral artery occlusion in rats.

In order to examine the effect of insulin-like growth factor-1 (IGF-1) on ischemic brain injury, IGF-1 was applied topically on the surface of reperfused rat brain after 60 min of transient middle cerebral artery occlusion (MCAO). In contrast to the cases treated with vehicle, the infarct area was greatly reduced at 24 h of reperfusion by treatment with IGF-1. Terminal deoxynucleotidyl transferase mediated dUTP-biotin in situ nick labeling (TUNEL) staining and immunoreactivity for glycogen synthase kinase 3beta (GSK3beta) were also markedly reduced in the brains with IGF-1 treatment. The present results suggest that the treatment with IGF-1 significantly ameliorates brain injury after transient focal brain ischemia associated with the reduction of TUNEL and GSK3beta stainings.