RESUMEN
OBJECTIVE To study the effects of the curcumin derivative bisdemethoxycurcumin （BC） promoting neuronal differentiation of neuroblastoma cells Neuro-2a （N2a） in mice and its mechanism. METHODS The effects of BC （1， 2， 4， 6， 8， 10 μmol/L） on the viability of N2a cells were detected by MTT assay to determine the concentration range of drug treatment. The control group， retinoic acid （RA） group （10 μmol/L） and BC groups （1， 2 and 4 μmol/L） were set up， and the length of neural protrusions of the differentiated cells was measured and the cell differentiation rate was calculated after 48 h and 72 h of culture. Compared with 0 min group， Western blot was used to detect the phosphorylation levels of protein kinase B （Akt）， extracellular- signal regulated kinase 1/2 （ERK1/2）， and p38 mitogen-activated protein kinase （p38） proteins in cells treated by 4 μmol/L BC for 5， 15， 30， 60， 120 min. After intervention with inhibitors LY294002 （LY） and PD98059 （PD）， the effects of BC on Akt and ERK1/2 protein phosphorylation levels and promoting neural differentiation were further validated. RESULTS According to the MTT experiment， the BC concentrations for subsequent induction of cell differentiation were determined to be 1， 2， and 4 μmol/L. After 48 hours of differentiation， compared with the control group， the cell differentiation rate in RA group and BC 1， 2 and 4 μmol/L groups， the length of cellular neural processes wjxhhxx413@163.com in the BC 4 μmol/L group significantly increased （P＜0.05 or P＜0.01）；after inducing differentiation of BC for 72 hours，compared with the control group， the cell differentiation rate and the length of cellular neural processes in the RA group， the cell differentiation rate in the BC 4 μmol/L group， and the length of cellular neural processes in the BC 2 μmol/L group all significantly increased （P＜0.05 or P＜0.01）.Compared with the 0 min group， the phosphorylation levels of Akt， ERK1/2， and p38 proteins in cells of the 5， 15， 30， 60 and 120 min groups increased to varying degrees after treated by 4 μmol/L BC， and some differences were statistically significant （P＜0.05 or P＜0.01）. After adding the inhibitor LY/PD， compared with the BC group， the phosphorylation level of ERK1/2 protein in the PD+BC group cells were significantly reduced （P＜0.01）， and the cell differentiation rates in the LY group， LY+BC group， PD group， and PD+BC group was significantly reduced （P＜0.01）. CONCLUSIONS BC promotes N2a cell differentiation mainly by increasing cell differentiation rate and neural protrusion length. The mechanism may be related to the activation of mitogen-activated protein kinase/ ERK and PI3K/Akt signaling pathways.