Selegiline Differentiates Adult Stem Cells toward Dopaminergic-Like Neurons: A Comparison between Two Cellular Niches of Hippocampal Neurogenesis

OBJECTIVE: Neural stem cells (NSCs) are suitable therapeutic candidates. Here, we compare the proliferation rate, differentiation potential, and expression levels of specific markers in two groups of cultured NSCs derived from rat subgranular (SGZ) and subventricular (SVZ) zones. MATERIALS AND METHODS: In this experimental study, NSCs isolated from SGZ and SVZ were cultured in α-minimal essential medium (α-MEM) supplemented with 1% penicillin/streptomycin, 10% fetal bovine serum (FBS), 20 ng/ml basic fibroblast growth factor (bFGF), 20 ng/ml epidermal growth factor (EGF), and B27 supplement. Glial fibrillary acidic protein (Gfap), p75 neurotrophin receptor (Ngfr), tyrosine kinase receptor A (TrkA), beta-tubulin III (βTIII), and Nestin gene levels were compared via reverse transcription polymerase chain reaction (RT-PCR) in these NSCs. Nestin and Gfap protein levels were compared by immunoassay. Subsequently, both populations were induced with 10(-8) M selegiline for 48 hours, followed by immunohistochemical analysis of tyrosine hydroxylase (TH) levels. One-way ANOVA and Tukey’s post-test were used with a significance level of P<0.05. RESULTS: Both groups were successfully expanded in vitro and expressed the neurotrophin receptor genes. The SGZNSCs had a significantly higher proliferation rate and significantly higher numbers of Nestin and Gfap-positive cells. Although the majority of selegiline-induced NSCs were TH-positive, we observed more TH-positive cells in SGZ-derived NSCs and these SGZ-NSCs displayed a shorter differentiation time. CONCLUSION: SGZ-derived NSCs appear to be a more appropriate candidate for therapeutic purposes based on proliferation rate, neurosphere size, and Gfap and Nestin expression levels, as well as differentiation time and TH expression level after dopaminergic induction.