Effects of induction time on dopaminergic neuronal differentiation from rat neural stem cells cultured in vitro

Chunlong KE; Baili CHEN; Huawei JIN; Shaolei GUO

ABSTRACT

BACKGROUND:

Recently, several scientists have found that differentiation of neural stem cells (NSCs) towards dopaminergic neurons may be increased in vitro by combination of some special cytokines. They have also found that dopaminergic neurons differentiated from NSCs can be used for the treatment of Parkinsn's disease. To improve the therapeutic effects of/n vitro transplantation, we should further study the biologic characteristics of NSCs at the induction and differentiation.

OBJECTIVE:

To explore the differentiation of NSCs which were incubated in differentiation solution for different time towards dopaminergic neurons in vitro.

DESIGN:

Single sample observation.

SETTING:

Department of Neurosurgery, First Affiliated Hospital of Sun Yat-sen University.MATERIALS This study was performed at the Department of Ncurosurgery, First Affiliated Hospital of Sun Yat-sen University from May to October 2007. Six healthy Sprague Dawley (SD) rats, gestational age 14 days, of clean grade, weighing 350-400 g,were provided by the Laboratory Animal Center, Sun Yat-sen University[permission No. SCXK (yue)2007-0034]. The protocol was performed in accordance with ethical guidelines for the use and care of animals.

METHODS:

NSCs derived from rat embryonic mesencephalon were cultured in serum-free culture medium containing epidermal growth factors and basic fibroblast growth factors. After passage, the NSCs were induced to differentiate towards dopaminergic neurons in the differentiation medium supplemented with interleukin 1o, interleukinl 1, human leukaemia inhibitory factors, and glial cell line-derived neurotrophic factors. The percentage of tyrosine hydroxylase positive neurons in differentiated ceils was detected with flow cytometer when NSCs were cultured in differentiation solution for 2, 4, 6, 8 and 10 days, respectively.MAIN OUTCOME

MEASURES:

Cellular morphological alteration of rat NSCs after differentiation. The percentage of tyrosine hydroxylase positive neurons in differentiated cells derived from NSCs.

RESULTS:

In differentiation medium, NSC spheres attached the bottom of plates and began to collapse. Cells inside the spheres grew out gradually and became irregular in shape. Six days later, most of the cells had I or 2 long processes and a few short processes. The percentage of tyrosine hydroxylase positive neurons in differentiated cells was respectively (3.2_+_0.9)%, (6.8 +1.6)%, (16.7-+2.6)%, (14.8_+1.8)% and (12.2_+2.5)% after culture for 2, 4, 6, 8 and 10 days, with significant differences (F =26.449, P ＜ 0.05).

CONCLUSION:

Induction time influences the differentiation of NSCs towards dopaminergic neurons in vitro. The percentage of dopaminergic neurons is the highest in differentiated cells derived from NSCs which are cultured in differentiation solution for 6 days.