Insulin growth factor-1 protects against excitotoxicity in the rat striatum

Recent findings demonstrated the neuroprotective effects of insulin-like growth factor 1 (IGF-1) in a cultured cell model of Huntington's disease. In the present study, we examined the potential neuroprotective effect of IGF-1 in vivo, in a rat model of Huntington's disease using the NMDA receptor agonist quinolinate. Continuous intracerebroventricular infusion of recombinant IGF-1 (0.25 μgh for 2 days) in the rat brain, produced a significant 8-fold increase in striatal levels of the growth factor. Histological evaluation after intrastriatal injection of quinolinate showed that IGF-1 treatment significantly attenuated striatal degeneration. These results further support the therapeutic interest of IGF-1 in Huntington's disease.