Intravenous administration of mesenchymal stem cells exerts therapeutic effects on parkinsonian model of rats: focusing on neuroprotective effects of stromal cell-derived factor-1alpha.

<bold>Background: </bold>Mesenchymal stem cells (MSCs) are pluripotent stem cells derived from bone marrow with secretory functions of various neurotrophic factors. Stromal cell-derived factor-1alpha (SDF-1alpha) is also reported as one of chemokines released from MSCs. In this research, the therapeutic effects of MSCs through SDF-1alpha were explored. 6-hydroxydopamine (6-OHDA, 20 microg) was injected into the right striatum of female SD rats with subsequent administration of GFP-labeled MSCs, fibroblasts, (i.v., 1 x 107 cells, respectively) or PBS at 2 hours after 6-OHDA injection. All rats were evaluated behaviorally with cylinder test and amphetamine-induced rotation test for 1 month with consequent euthanasia for immunohistochemical evaluations. Additionally, to explore the underlying mechanisms, neuroprotective effects of SDF-1alpha were explored using 6-OHDA-exposed PC12 cells by using dopamine (DA) assay and TdT-mediated dUTP-biotin nick-end labeling (TUNEL) staining.<bold>Results: </bold>Rats receiving MSC transplantation significantly ameliorated behaviorally both in cylinder test and amphetamine-induced rotation test compared with the control groups. Correspondingly, rats with MSCs displayed significant preservation in the density of tyrosine hydroxylase (TH)-positive fibers in the striatum and the number of TH-positive neurons in the substantia nigra pars compacta (SNc) compared to that of control rats. In the in vitro study, SDF-1alpha treatment increased DA release and suppressed cell death induced by 6-OHDA administration compared with the control groups.<bold>Conclusions: </bold>Consequently, MSC transplantation might exert neuroprotection on 6-OHDA-exposed dopaminergic neurons at least partly through anti-apoptotic effects of SDF-1alpha. The results demonstrate the potentials of intravenous MSC administration for clinical applications, although further explorations are required. [ABSTRACT FROM AUTHOR]