Protective effects of intracerebral adenoviral-mediated GDNF gene transfer in a rat model of Parkinson's disease

This study focuses on the potential protective effects of intracerebral adeno-viral mediated glial cell line derived neurotrophic factor (GDNF) gene transfer in a rat model of Parkinson's disease (PD). Thirty-five SD rats were divided into three groups to receive perinigral injections of recombinant adenovirus encoding GDNF (Ad-GDNF), LacZ (Ad-LacZ) or PBS, respectively. One week later, an intrastriatal injection of 6-hydroxydopamine (6-OHDA) was administered to induce the progressive degeneration of dopaminergic neurons. Immunohistochemistry showed that GDNF treatment prior to neuronal damage could promote survival and morphological recovery of tyrosine hydroxylase (TH)-positive neurons in the midbrain. Approximately 70% of nigral TH-positive cells survived in the Ad-GDNF group, compared to approximately 30% for the Ad-LacZ or PBS control group. Histochemical analysis of monoamine levels in the striatum demonstrated that the dopamine content was higher for the Ad-GDNF group than the control groups. Similarly, Ad-GDNF treated animals showed improved apomorphine-induced rotational behavior. The exogenous GDNF gene was efficiently expressed in the brain as detected by ELISA. This work demonstrates that intracerebral adeno-viral mediated GDNF gene transfer can protect dopaminergic neurons in vivo from 6-OHDA-induced injuries. The approach used in this study could potentially be used therapeutically in patients with PD and further work is required to explore this idea in depth. (C) 2003 Elsevier Ltd. All rights reserved.