Curcumin increased the differentiation rate of neurons in neural stem cells via wnt signaling in vitro study

Background: The objective of the present study was to clarify the relationship between the neuroprotective effects of curcumin and the classical wnt signaling pathway. Method: Using Sprague-Dawley rats at a gestational age of 14.5 d, we isolated neural stem cells from the anterior two-thirds of the fetal rat brain. The neural stem cells were passaged three times using the half media replacement method and identified using cellular immunofluorescence. After passaging for three generations, we cultured cells in media without basic fibroblast growth factor and epidermal growth factor. Then we treated cells in five different ways, including a blank control group, a group treated with IWR1 (10 mu mol/L), a group treated with curcumin (500 nmol/L), a group treated with IWR1 + curcumin, and a group treated with dimethyl sulfoxide (10 mu mol/L). We then measured the protein and RNA expression levels for wnt3a and beta-catenin using Western -blotting and Reverse transcription-polymerase chain reaction (RT-PCR). Results: Western-blotting: after the third generation of cells had been treated for 72 h, we observed that wnt3a and beta-catenin expression was significantly increased in the group receiving 500 nmol/L curcumin but not in the other groups. Furthermore, cells in the IWR1-treated group showed decreased wnt3a and beta-catenin expression, and wnt3a and beta-catenin was also decreased in the IWR1 + 500 nmol/L curcumin group. No obvious change was observed in the dimethyl sulfoxide group. RT-PCR: RT-PCR showed similar changes to those observed with the Western blotting experiments. Conclusions: Our study suggests that curcumin can activate the wnt signaling pathway, which provides evidence that curcumin exhibits a neuroprotective effect through the classical wnt signaling pathway. (C) 2014 Elsevier Inc. All rights reserved.