Transplantation of Deprenyl-Induced Tyrosine Hydroxylase-Positive Cells Improves 6-OHDA-Lesion Rat Model of Parkinson's Disease: Behavioral and Immunohistochemical Evaluation

There is longstanding experimental and clinical evidence that supports the idea that replacement of dopaminergic (DAergic) neurons can ameliorate functional disabilities of Parkinson’s disease (PD). The purpose of the present study is to examine the efficacy of transplantation of rat bone marrow stromal cell (BMSCs)-derived tyrosine hydroxylase-positive (TH+) cells induced by deprenyl into 6-hydroxydopamine (6-OHDA)-lesioned rat models, using behavioral tests and immunohistochemical evaluations. In this experimental study, undifferentiated BrdU-labeled BMSCs were incubated in serum-free medium that contained 10-8 M deprenyl for 24 hours. Afterwards, BMSCs were cultured for 48 hours in α-minimal essential medium (α-MEM) supplemented with 10% FBS, then differentiated into TH+ neurons. We randomly divided 24 hemiparkinsonian rats as follows: group 1 (control) received only medium, while groups 2 and 3 were injected with 2×105 BMSCs and deprenyl-treated cells in 4 μl medium. Injections were made into the injured strata of the rats. Rotational behavior in response to apomorphine was tested before transplantation and at 2, 4, and 6 weeks post-graft. Animals were then sacrificed, and the brains were extracted for immunohistochemical and electron microscopic studies. Apomorphine-induced rotation analysis indicated that animals with grafted cells in groups 2 and 3 exhibited significantly less rotational behavior than those in the control group at 2, 4, and 6 weeks after transplantation. Immunohistochemical analysis demonstrated that BrdU-labeled cells expressed specific neuronal markers, such as NF 200 and TH, at the implantation site. The presence of TH+ cells in conjunction with the reduction in rotation might show the capacity of grafted cells to release dopamine. Ultrastructural analysis revealed the presence of immature neurons and astrocyte-like cells at the graft site. TH+ neurons induced by deprenyl can be considered as a cell source for PD autograft therapy.