Objective:To investigate the effects of Panax notoginseng saponins(PNS)on the proliferation and differentiation in NIH3T3 cells.Methods:NIH3T3 cells were treated by various concentrations of PNS 0,0.05, 0.10,0.20,and 0.40 g/L.The vitality and proliferation potential of cells were detected by 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide(MTT)assay,the alkaline phosphatase(ALP)activity was measured by p-nitrophenyl phosphate(pNPP)assay,and the mineralization formation ability was tested for the cellular differentiation toward osteoblast,as well as the expression level of phosphorylated extracellular signal-regulated kinasel/2(P-ERK1/2),extracellular signal-regulated kinasel/2(ERK1/2)protein kinase was analyzed by Western blot with total cell lysate of NIH3T3 cells treated by PNS.Results:Both MTT andρNPP assay showed that optical density(OD)values were increased in response to PNS treatment at a dose-dependent pattern. The mineralization formation ability was enhanced in PNS-treated NIH3T3 cells compared with untreated cells. Meanwhile,the expression level of P-ERK1/2 protein kinase was up-regulated in PNS-treated NIH3T3 cells, while,the expression level of ERK1/2 protein kinase revealed no obvious difference with or without PNS treated cells.Conclusion:PNS could pay a role to promote the proliferation and differentiation in NIH3T3 cells by means of up-regulation of P-ERK1/2 protein kinase. Objective: To investigate the effects of Panax notoginseng saponins (PNS) on the proliferation and differentiation in NIH3T3 cells. Methods: NIH3T3 cells were treated with various concentrations of PNS 0,0.05, 0.10,0.20, and 0.40 g / L.The vitality and proliferation potential of cells were detected by 3- (4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide (MTT) assay, the alkaline phosphatase (ALP) activity was measured by p-nitrophenyl phosphate , and the mineralization formation ability was tested for the cellular differentiation toward osteoblast, as well as the expression level of phosphorylated extracellular signal-regulated kinasel / 2 (P-ERK1 / 2), extracellular signal-regulated kinasel / 2 protein kinase was analyzed by Western blot with total cell lysate of NIH3T3 cells treated by PNS. Results: Both MTT and pNPP assay showed that optical density (OD) values ​​were increased in response to PNS treatment at a dose- dependent pattern. The mineralization formation ability was enhanced in PNS-treated NIH3T3 cells were compared with untreated cells. Meanwhile, the expression level of P-ERK1 / 2 protein kinase was up-regulated in PNS-treated NIH3T3 cells, while, the expression level of ERK1 / 2 protein kinase revealed no obvious difference with or without PNS treated cells. Conlusion: PNS could pay a role to promote the proliferation and differentiation in NIH3T3 cells by means of up-regulation of P-ERK1 / 2 protein kinase.