Intraventricular infusion of epidermal growth factor restores dopaminergic pathway in hemiparkinsonian rats

We assessed the effect of a 35-day delayed intracerebroventricular (ICV) infusion of epidermal growth factor (EGF) on the survival and function of the substantia nigra (SN) dopaminergic neurons after a unilateral mechanical transection of rat nigrostriatal pathway. EGF infusion for 28 days resulted in a twofold increase in the number of surviving tyrosine-hydroxylase (TH)-positive SN neurons and a significant increase in ipsilateral striatal TH-positive fiber staining compared to controls at 200 days following the injury. In addition, there was a persistent enhancement of behavioral recovery, as indicated by a reduction in amphetamine-induced rotations. We conclude that EGF exerts a neurotrophic effect on the dopaminergic neurons in this experimental model of parkinsonism.