Reduction of ischemic damage by application of insulin-like growth factor-1 in rat brain after transient ischemia.

In order to investigate a possible effect of insulin-like growth factor-1 (IGF-1) on ischemic brain injury, IGF-1 was applied topically on the brain surface of reperfused rat brain after 60 min of transient middle cerebral artery occlusion. In contrast to the cases treated with vehicle, the infarct volume was greatly reduced at 24 h of reperfusion by the treatment with IGF-1. Immunohistochemical analysis in the middle cerebral artery territory showed that Caspase-3 staining was markedly reduced in the cases with IGF-1 treatment, but 72-kDa heat shock protein staining remained almost unchanged. The present results suggest that treatment with IGF-1 exerts a significant effect on ameliorating brain injury after transient focal brain ischemia. Moreover, this effect is greatly associated with the reduction of Caspase-3 staining, but is only minimally associated with a decreasd stress response at the cellular level.