The Journal of Neuroscience, April 1, 2003, 23(7):2797
Adeno-Associated Virus Vector Expressing Nerve Growth
Factor Enhances Cholinergic Axonal Sprouting after Cortical Injury in
Rats
Julio J.
Ramirez1, 2,
Jennifer L.
Caldwell2,
Melanie
Majure2,
David R.
Wessner3,
Ronald L.
Klein4,
Edwin M.
Meyer4, and
Michael A.
King5, 6
1 Department of Psychology, 2 Neuroscience
Program, and 3 Department of Biology, Davidson College,
Davidson, North Carolina 28035, Departments of
4 Pharmacology and 5 Neuroscience,
University of Florida, Gainesville, Florida 32610, and
6 Veterans Administration Medical Center, Gainesville,
Florida 32608
Nerve growth factor (NGF) is known to promote both the survival of
cholinergic neurons after injury and the regeneration of damaged
cholinergic axons. Recent evidence has implicated NGF in the regulation
of cholinergic axonal sprouting by intact neurons projecting to the
hippocampus of rats, sustaining a lesion of the entorhinal cortex. We
explored the possibility that NGF may regulate this lesion-induced
cholinergic sprouting by injecting recombinant adeno-associated virus
(rAAV) vector expressing NGF and green fluorescent protein (GFP) into
the dentate gyrus of rats that were subsequently given unilateral
entorhinal lesions. Sprague Dawley rats were unilaterally
injected with (1) rAAV vector expressing NGF and GFP or (2) rAAV vector
expressing GFP. Fourteen days after injection, the animals received
lesions of the entorhinal area ipsilateral to the virus injection. Four
days after lesion, GFP expression and the septodentate sprouting
response in the dentate gyrus were assessed. Optical densitometric
analyses revealed a significant increase in acetylcholinesterase label
(a marker for cholinergic septodentate sprouting) in the ipsilateral
outer molecular layer of the dentate gyrus in rats injected with rAAV vector expressing NGF. Thus, NGF-expressing rAAV vector enhanced the
sprouting response of intact cholinergic neurons after unilateral entorhinal lesions in rats.
Key words:
acetylcholinesterase; dentate gyrus; entorhinal
cortex; hippocampus; neuroplasticity; nerve growth factor; reactive
synaptogenesis; sprouting; trophic factor
Copyright © 2003 Society for Neuroscience 0270-6474/03/2372797-07$05.00/0