| Objective To study the effect of Icariside Ⅰ and Icariside Ⅱ on promoting osteogenic differentiation of bone marrow stromal cells (BMSCs) by activating the BMP-2/Runx2/OSX signaling pathway, and to explore its possible mechanism. Methods By using the adherence method, BMSCs were cultured and divided into blank control group, positive control group, inhibitor group, Icariside Ⅰ control and Icariside Ⅰ+ inhibitor group, Icariside Ⅱ and Icariside Ⅱ+ inhibitor group. Osteoblasts differentiation was evaluated using Alizarin red staining. The protein expression of ALP, BGP, COL-Ⅰ, and BMP-2 was detected with ELISA method. The expression of ALP, BGP, Osterix, and Runx-2 genes was detected with real-Time RT-PCR. Results The Results of Alizarin red staining showed that a large number of mineralized nodules were formed in Icariside I and Icariside II groups. The ELISA results showed that both Icariside I and Icariside II significantly promoted the activity of ALP and the secretion of BGP, COL-I, and BMP-2 proteins (P<0.05). The strength of action in both groups reached more than 80 % of that in the positive control group. Meanwhile, the effect of Icariside I on ALP activity and BGP protein was significantly stronger than that of Icariside II (P<0.05). The effect was not significantly different in the protein expression of COL-I and BMP-2 (P＞0.05). RT-PCR results showed that Icariside I and Icariside II significantly increased ALP, BGP, RunX2, and further regulated the transcription expression of the downstream gene Osterix, with significant differences compared with the blank control group. The mRNA expression of ALP and Osterix was not significantly different between Icariside II and positive contrast group (P>0.05). The expression of Osterix mRNA in Icariside II group was higher than that in Icariside I group, and there was significant difference (P<0.05). The mRNA expression of ALP, BGP, and RunX2 was not significantly different (P>0.05). Conclusion Both Icariside I and Icariside II promote osteogenesis by BMSCs. The mechanism of action may be related to the activation of the BMP/Runx2/Osx signal pathway. The different effects between Icariside I and the Icariside II may be related to the biotransformation of Icariside I into Icariside II. |