Introduction: Adult neurogenesis, the process of generating new neuron cells in adult CNS, continues throughout life, despite past perceptions. Unfortunately, this process is insufficient in pathological conditions and needs to be promoted by nutritional and pharmacological stimulants. Crocin, the active component of Saffron, is a carotenoid that affects neurogenesis in vivo and in vitro. Our aim in the present study was to investigate the enhancing effects of crocin on the neurogenesis of adipose-derived mesenchymal stem cells (ADSC) in the presence of retinoic acid, as well as the molecular pathways involved.
Material and methods: Stemness potential and differentiation capacity of harvested ADSC cells were evaluated. The optimum dose of crocin was assessed with an MTT assay. Crocin, retinoic acid, CREB/BDNF, and Notch inhibitors alone and in combination were added to the cell culture medium. Jag1, Hes1, Notch, and BDNF gene expression were analyzed by q-RTPCR on days 7, 14, and 21, while CREB, DCX, SOX2, and NeuN expression in the different groups were analyzed by Immunofluorescence (IF) method.
Results: Expression of mesenchymal CD markers as well as adipogenic and osteogenic differentiation confirmed the origin and properties of ADSCs. The optimal dose of crocin for in-vitro use was 1mM. Administration of crocin significantly (P<0.05) increased, while administration of inhibitors (DATP & Naphthol) significantly (P<0.05) decreased in Jag1, Hes1, Notch, and BDNF expression. Immunofluorescent assessments showed that expression of DCX, BDNF, NeuN, and Sox2 proteins increased significantly (P<0.05) after crocin administration and decreased significantly (P<0.05) after administration of the inhibitor.
Conclusion: It can be concluded that crocin can be used as an enhancer for neural differentiation of MSCs in-vitro in the presence of retinoic acid. The mechanism is proposed through Notch and CREB/BDNF signaling pathways. Whether these effects can occur in vivo requires more extensive studies.