Effects of panax notoginseng saponins on the osteogenic differentiation of rabbit bone mesenchymal stem cells through TGF-β1 signaling pathway

Background: Panax Notoginseng is a well-known Chinese medicinal herb which has been used in China for treatment of bone fracture for hundreds of years. However, the specific biological mechanisms of osteogenic effect of PNS are not well understood.

Methods: In this study, newborn rabbit BMSCs were isolated, and then identified by the positive expression rates of cell surface markers, including CD29, CD45 and HLA-DR, which were detected by flow cytometry(FCM). After the lentivirus-induced cell model of TGF-β1 gene silencing was established, the interference efficiency was tested by q-PCR and Western blot, and the growth curve of silencing cells was drawn by MTT so as to grasp the growth rhythm of silencing cells. In the alizarin red-staining experiment, the effect of 100 mg/L PNS on the activity of intracellular ALP of TGF-β1 gene silencing BMSCs was detected, so as to observe the effect of 100 mg/L PNS on the formation of calcium nodes of gene silencing BMSCs.

Results: By separating rabbit BMSCs, the lentivirus-induced cell model of TGF-β1 gene silencing was established. Both TGF-β1 mRNA and protein expression were restrained significantly, and the target gene kept silence stably via the verification of q-PCR and Western blot; there was no significant differences of the growth curve between RNAi cells and normal cells; the activity of intracellular APL in 100 mg RNAi group was obviously lower than that in 100 mg group (p < 0.05), but higher than that in the normal group; in the alizarin red-staining experiment, it focused on the effects of PNS on the formation of calcium nodes of gene silencing BMSCs, which showed that calcium nodes could be formed in 100 mg RNAi group but its quantity was lower than that of 100 mg group (p < 0.05).

Conclusions: It was shown that silencing TGF-β1 gene could interrupt the osteogenic effects of PNS. PNS may have a promoting effect on osteogenic differentiation of rabbits' BMSCs in vitro by up-regulating the gene expression of TGF-β1.