Insulin-like growth factor-1 affects expressions of cyclin-dependent kinase 5 and its activator p35 in reperfused rat brain

Insulin-like growth factor-1 (IGF-1) was applied topically on the brain sur face of reperfused rat brain after 60 min of transient middle cerebral arte ry (MCA) occlusion. In contrast to the cases treated with vehicle, the infa rct volume was greatly reduced at 24 h of reperfusion by the treatment with IGF-1. Immunohistochemical analysis in the MCA territory showed that the i ncrease of cyclin-dependent kinase 5 (cdk5) was greatly reduced, and that t he decrease of the critical regulatory subunit of cdk5, p35, was preserved with treatment of IGF-1. The present results suggest that IGF-1 has a signi ficant effect on ameliorating brain injury after transient focal brain isch emia with affecting the expressions of cdk5 and its activator p35. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.