Effect of selegiline on neural stem cells differentiation: a possible role for neurotrophic factors

Abstract

Objectives: The stimulation of neural stem cells (NSCs) differentiation into neurons has attracted great attention in management of neurodegenerative disease and traumatic brain injury. It has been reported that selegiline could enhance the morphologic differentiation of embryonic stem cells. Therefore this study aimed to investigate the effects of selegiline on NSCs differentiation with focus on the role of neurotrophic factor gene expression.

Materials and methods: The NSCs were isolated from lateral ventricle of C57 mice brain. The cells were exposed to selegiline in nano to micromolar concentrations for 24 hr or 72 hr. In order to assay the effect of selegiline on NSCs differentiation into neurons, astrocytes and oligodendrocytes, immunocytochemical techniques were utilized. Samples were exposed to specific antibodies against neurons (β tubulin), astrocytes (GFAP) and oligodendrocytes (OSP). The expression of BDNF, NGF and NT3 genes was investigated using Real-Time PCR.

Results: Our findings revealed that selegiline increased NSCs differentiation into neurons at 10(-7) and 10(-8) M and decreased the differentiation into astrocytes at 10(-9), while oligodendrocyte did not significantly change in any of the used concentrations. In addition data analyses showed that selegiline increased BDNF, NGF and NT3 gene expression at 24 hr, but did not change them in the other time of exposure (72 hr) except 10(-7) M concentration of selegiline, which increased NT3 expression.

Conclusion: Our results indicate selegiline induced the differentiation of NSCs into neurons and in this context the role of neurotrophic factors is important and should be considered.

Keywords: NSCs; Neurotrophic factors; Selegiline.

Figure 1

Phase contrast and fluorescent illustration of primary (a) and secondary (b) neurospheres. The nestin immunoreactivity is shown in a neurosphere (C). Scale bar = 200 μm

Figure 2

Neural stem cells differentiation. Quantification of differentiation of NSCs into neuron (a), astrocyte (b) and oligodendrocyte (c) after 72 hr exposure to different concentrations of selegiline. The data represent the mean ± sem percent of differentiation. The illustrations represent the β tubulin positive cells as neuron marker (d), GFAP positive cells as astrocyte marker (e) and OSP positive cells as oligodendrocyte marker (f). Experiments were performed in triplicate and P-values <0.05 were considered to be significant in all analyses. ** P<0.01, *** P <0.001 in comparison with the control group (0 selegiline concentration). M=Molar

Figure 3

Data of Real-Time PCR regarding BDNF (a), NGF (b) and NT3 (c) gene expression after 24 or 72 hr exposure to selegiline. Experiments were performed in triplicate and P-values <0.05 were considered to be significant in all analyses. * P<0.05, *** P <0.001 in comparison with the control group (0 selegiline concentration). M=Molar