Fig. 1

Secretome from human fetal mesenchymal stem cells (hFMSCs) had more osteogenic potential and lower immunogenicity than that from rat bone marrow-derived mesenchymal stem cells (r BMSCs) and human adult mesenchymal stem cells (hAMSCs), as well as no effect on cell viability. a Both the alkaline phosphatase (ALP) staining and Alizarin Red S staining showed that more calcium deposits could be found after hFMSC secretome treatment. b The semi-quantitative results of Alizarin Red S staining demonstrated that significantly more mineralization was seen in the hFMSC secretome group. c Immunogenicity was determined by mixed rat peripheral blood lymphocyte reaction. The hFMSC secretome had no significant effect on rat peripheral blood lymphocyte proliferation. d Significant lymphocyte proliferation was stimulated after administration of hAMSC secretome. e Cell viability was evaluated by the MTT assay. The optical density (OD) level of rBMSCs treated with hFMSC secretome showed no significant difference among the doses from 10 μg/μl to 200 μg/μl. *p < 0.05, **p < 0.01. d days