Bone resorption improvement by conditioned medium of stem cells from human exfoliated deciduous teeth in ovariectomized mice

Stem cells from human exfoliated deciduous teeth (SHED) are mesenchymal stem cells with multipotent differentiation potential present in the dental pulp tissue of the deciduous teeth. SHED produce secretions that have immunomodulatory and regenerative functions. In the present study, we investigated the effects of SHED-conditioned medium (SHED-CM) on osteopenia induced by the ovariectomy (OVX) phenotype and its corresponding immunological changes. Eleven-week-old female C3H/HeJ mice were subjected to OVX. SHED-CM was administered intraperitoneally in these mice for 4 weeks starting immediately after OVX. SHED-CM improved bone mass after OVX and elevated the polarization of M2 macrophages in the peritoneal cavity. SHED-CM also suppressed an OVX-induced increase in interferon-gamma (INF-gamma) and interleukin-17 (IL-17) concentrations in the peripheral blood. Inhibition of M2 macrophage polarization with neutralizing antibodies did not reduce the concentration of IFN-gamma and IL-17 in peripheral blood, which were increased by OVX, and did not alleviate osteopenia induced by the OVX phenotype. Mechanistically, these findings suggest that SHED-CM alleviates bone resorption by suppressing the activation of IFN-gamma and IL-17 cells by polarizing M2 macrophages. In conclusion, our data indicate that SHED-CM contains active secretions that may have promising efficacy to ameliorate OVX-induced osteopenia. We suggest that SHED-CM has the potential to be used as a novel therapeutic agent to inhibit osteoporosis.