The Journal of Neuroscience, April 15, 2001, 21(8):2889-2896
Growth and Functional Efficacy of Intrastriatal Nigral
Transplants Depend on the Extent of Nigrostriatal Degeneration
Deniz
Kirik,
Christian
Winkler, and
Anders
Björklund
Wallenberg Neuroscience Center, Department of Physiological
Sciences, Lund University, 22184, Lund, Sweden
Previous studies have shown that the functional efficacy of
intrastriatal transplants of fetal dopamine (DA) neurons in the rat
Parkinson model depends on their ability to establish a new functional
innervation of the denervated striatum. Here we report that the
survival, growth, and function of the grafted DA neurons greatly depend
on the severity of the lesion of the host nigrostriatal system. Fiber
outgrowth, and to a lesser extent also cell survival, were
significantly reduced in animals in which part of the intrinsic DA
system was left intact. Moreover, graft-induced functional recovery, as
assessed in the stepping, paw-use, and apomorphine rotation tests, was
obtained only in severely lesioned animals, i.e., in rats with >70%
DA denervation of the host striatum. Functional recovery seen in these
animals in which the 6-hydroxydopamine (6-OHDA) lesion was confined to
the striatum was more pronounced than that previously obtained in rats
with complete lesions of the mesencephalic DA system, indicating that
spared portions of the host DA system, particularly those innervating
nonstriatal forebrain areas, may be necessary for the grafts to exert
their optimal functional effect. These data have implications for the optimal use of fetal nigral transplants in Parkinson patients in
different stages of the disease.
Key words:
Parkinson's disease; 6-hydroxydopamine; transplantation; sensorimotor behavior; stepping; paw use; tyrosine hydroxylase; stereology
Copyright © 2001 Society for Neuroscience 0270-6474/01/2182889-08$05.00/0