Reduction of ischemic brain injury by topical application of glial cell line-derived neurotrophic factor after permanent middle cerebral artery occlusion in rats.
OBJECTIVE
Glial cell line-derived neurotrophic factor (GDNF) plays important roles in the survival and recovery of some mature neurons under pathological conditions. However, the effect of GDNF in ameliorating ischemic brain injury has not been well documented. Therefore, we investigated a possible effect of GDNF on the changes of infarct size, brain edema, DNA fragmentation, and immunoreactivities for caspases after permanent middle cerebral artery occlusion (MCAO) in rats.


METHODS
For the estimation of ischemic brain injury, we calculated the infarct size of MCA region and also measured the brain water content as edema formation at 24 hours after the MCAO. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin in situ nick labeling (TUNEL) staining was performed for the detection of DNA fragmentation. Immunoreactivities for caspase-1 (ICE), caspase-2 (Nedd-2), and caspase-3 (CPP32) were stained.


RESULTS
Both infarct size and brain edema after permanent MCAO were significantly reduced by topical application of GDNF (48% and 30% decreases, P=0.01). TUNEL staining and immunoreactivities for caspases were markedly induced at 12 hours after permanent MCAO in the vehicle-treated animals. However, the spatial distribution of those immunohistochemically positive cells was dissociative in each caspase. Induction of TUNEL staining and immunoreactivities for caspases-1 and -3 was greatly reduced with GDNF treatment, whereas the reduction of caspase-2 staining was only minimum.


CONCLUSIONS
These data suggest that the reduction of infarct size and brain edema by GDNF was greatly associated with the reduction of DNA fragmentation and apoptotic signals predominantly through caspases-1 and -3 cascades.
Kitagawa
H
H
Department of Neurology, Tohoku University School of Medicine, Sendai, Japan.
Hayashi
T
T
Mitsumoto
Y
Y
Koga
N
N
Itoyama
Y
Y
Abe
K
K
D000287:Administration, Topical; D000818:Animals; D001157:Arterial Occlusive Diseases / Q000150:complications*; D001834:Body Water / Q000378:metabolism; D001921:Brain / Q000201:enzymology; D001929:Brain Edema / Q000378:metabolism; D002545:Brain Ischemia / Q000209:etiology* / Q000473:pathology*; D002536:Cerebral Arteries; D002544:Cerebral Infarction / Q000473:pathology; D003546:Cysteine Endopeptidases / Q000378:metabolism; D053938:DNA Fragmentation / Q000187:drug effects; D005821:Genetic Techniques; D051100:Glial Cell Line-Derived Neurotrophic Factor; D007150:Immunohistochemistry; D008297:Male; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins / Q000494:pharmacology*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
C495041:Gdnf protein, rat; D051100:Glial Cell Line-Derived Neurotrophic Factor; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D018696:Neuroprotective Agents; D003546:Cysteine Endopeptidases