Abstract:

Objective To explore the effects of emodin on proliferation and differentiation of MC3T3-E1 preosteoblasts and the possible mechanism. Methods The treated group contained MC3T3-E1 cells treated by emodin of different concentrations (0.05, 0.1, 0.5, 2.0, and 5.0 μmol/L) and the control group contained MC3T3-E1 cells not treated by emodin. The cell proliferation rate was detected by the MTT assay. The activity of ALP was determined by the quantitative PNPP method. The alizarin red staining was used to observe the number of mineralized nodules. The expression of signaling molecules relevant to BMP pathway was detected by the RT-PCR. The activity of ALP was measured and the effects of BMP-9 on the differentiation of osteoblasts were observed after cells were treated by Noggin, which was a BMP-specific inhibitor. Results Emodin had no effect on the proliferation of MC3T3-E1 cells. Emodin increased the expression of ALP and formation of mineralized nodules at the concentrations from 0.5 μmol/L to 5 μmol/L, especially at the concentration of 5 μmol/L. Emodin enhanced the expression of BMP-9 and expressions of upstream and downstream signaling molecules relevant to BMP-9 pathway also changed accordingly. The emodin-induced differentiation of osteoblasts was inhibited after being pretreated by Noggin. Conclusion Emodin can promote the differentiation of preosteoblasts by activating the signaling pathway of BMP-9.

Key words: emodin, preosteoblast, differentiation, bone morphogenetic protein 9