Long-term effect of intra-striatal glial cell line-derived neurotrophic factor-releasing microspheres in a partial rat model of Parkinson's disease.

Glial cell line-derived neurotrophic factor (GDNF) offers the possibility to stimulate axonal regeneration of mesencephalic dopaminergic neurons, which are affected in Parkinson's disease. Nevertheless, a safe and efficient GDNF delivery system that may be used in clinical trials is still lacking. In a previous study, we showed that GDNF-releasing microspheres can deliver the neurotrophic factor for 2 months, allowing in a partial rat model of Parkinson's disease a sprouting of the preserved dopaminergic fibers and functional improvement 8 weeks after the treatment. The present study confirms these previous observations and shows that the amphetamine-induced rotation score is still decreased 24 weeks after the end of GDNF delivery. Nevertheless, the improvement was not statistically significant at the latest time point due to the spontaneous reinnervation observed in the model used.