Adenovirus-mediated glial cell line-derived neurotrophic factor gene delivery reduces motor neuron injury after transient spinal cord ischemia in rabbits.
OBJECTIVE
Glial cell line-derived neurotrophic factor (GDNF) has protective effects on various injuries involving the central and peripheral nervous systems in vitro and vivo. However, the possible protective effect of GDNF on spinal cord ischemia and the exact mechanism involved in the ameliorative effect of GDNF on ischemic spinal cord injuries are not fully understood. Therefore, we investigated the possible protective effect of the adenovirus-mediated GDNF gene delivery on transient spinal cord ischemia in rabbits.


METHODS
The adenoviral vector (lacZ gene as a control or GDNF gene contained) was injected directly into the lumbar spinal cord via a needle inserted into the dorsal spine 2 days before the animal was subjected to 15 minutes of spinal cord ischemia induced by infrarenal aortic occlusion. In situ terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick-end labeling (TUNEL staining) was performed, and temporal profiles of the GDNF and caspase-3 (caspase-3 is the marker of apoptotic change) immunoreactivity were investigated.


RESULTS
In the control rabbit, the majority of motor neurons showed selective cell death at 7 days of reperfusion. Immunocytochemistry showed that in situ TUNEL staining was selectively detected at 2 days of reperfusion in motor neuron nuclei. GDNF and caspase-3 were selectively induced in the motor neuron cells at 8 hours of reperfusion. In the GDNF-treated group, a large population of motor neuron cells was still surviving at 7 days after having been subjected to 15 minutes of ischemia. Unlike the control group, the GDNF-treated group expressed GDNF persistently. Induction of TUNEL staining and immunoreactivity for caspase-3 were greatly reduced by the GDNF treatment.


CONCLUSIONS
These results suggest that the reduction in motor neuron death by GDNF was greatly associated with a reduction in DNA fragmentation and apoptotic signals of the caspase-3 cascade; they further suggest a great potential for gene therapy for paraplegic patients in the future.
Sakurai
M
M
Department of Cardiovascular Surgery, Graduate School of Medicine, Tohoku University, Sendai, Japan.
Abe
K
K
Hayashi
T
T
Setoguchi
Y
Y
Yaginuma
G
G
Meguro
T
T
Tabayashi
K
K
D000256:Adenoviridae; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3; D020169:Caspases / Q000032:analysis; D053938:DNA Fragmentation / Q000187:drug effects; D004195:Disease Models, Animal; D016503:Drug Delivery Systems / Q000379:methods*; D004353:Drug Evaluation, Preclinical; D018014:Gene Transfer Techniques; D005822:Genetic Vectors / Q000627:therapeutic use*; D051100:Glial Cell Line-Derived Neurotrophic Factor; D020287:In Situ Nick-End Labeling; D007763:Lac Operon; D009046:Motor Neurons / Q000187:drug effects*; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins / Q000008:administration & dosage* / Q000494:pharmacology; D018696:Neuroprotective Agents / Q000008:administration & dosage* / Q000494:pharmacology; D011817:Rabbits; D020760:Spinal Cord Ischemia / Q000209:etiology / Q000517:prevention & control*
D051100:Glial Cell Line-Derived Neurotrophic Factor; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D018696:Neuroprotective Agents; D053148:Caspase 3; D020169:Caspases