Cysteine: a novel neural inducer for rat bone marrow mesenchymal stem cells.

Objective: Mesenchymal stem cells (MSCs) can differentiate into various cell types. Since cysteine has structural similarities to neuronal inducers β-mercaptoethanol and glutathione, we examined its effect on neural induction of rat bone marrow MSCs. Materials and Methods: In this experimental study, cells were treated in a medium containing 1mM cysteine for 24 hours prior to treatment with neuron inducing medium containing 10 mM cysteine for 1, 2 and 3 hours. Cell viability and morphology were assessed by 3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide (MTT) assay and, Hoechst, propidium iodide and acridine orange staining respectively. Expression of nestin and β-Tubulin III genes, as neural cell-specific markers, was studied reverse transcription polymerase chain reaction (RT-PCR). The data was statistically analyzed using One-Way ANOVA and Tukey’s test and p<0.05 was considered significant. Results: After 3 hours of treatment, neuron like morphology with a considerable expression of nestin and β-Tubulin III genes was apparent. The mean cell viability was not significantly different at 1, 2 and 3 hours following induction, compared with the control cells. Conclusion: Cysteine can induce neural features in rat bone marrow MSCs without reducing cell viability. Therefore, it can be considered as a safer alternative to toxic neural inducer agents such as β-mercaptoethanol.