In vitro Dose Assessment of Marrow-Derived Mesenchymal Stem Cell Chemotactic Factors for Enhanced Musculoskeletal Tissue Regeneration

Abstract

Regenerative medicine is a growing field that utilizes mesenchymal stem cells (MSCs) to repair damaged tissues. When induced, MSCs will migrate from tissues like bone marrow (BM)to sites of injury. Proteins known as chemokines can influence chemotaxis. In previous research, the chemokines RANTES, SDF-1 p, MIP-3oc, and MCP-1 have shown varied results with regard to inducing chemotaxis and proliferation of MSCs. However, these four chemokines have yet to be assessed together under the same experimental procedures. In the present study, rat BM MSCs were exposed to murine recombinants of the above chemokines at the median effective dose (ED50) and concentration for maximum biological activity (Cmax) in order to assess their ability to induce chemotaxis and cell proliferation. Since the concentrations for these doses have yet to be determined for rat BM MSCs, concentrations previously determined on other cell lines were used in this study. A Boyden Chamber assay was used to measure chemotaxis and an AlamarBlue assay was performed to measure cell proliferation and viability. We found thatMCP-1 showed significantly greater chemotaxis than controls at the ED50 dose, while SDF-1 p andMIP-3ashowed significantly greater chemotaxis at the Cmax dose. From the AlamarBlue assay, we found that MIP-3a and MCP-1 caused significant increases in cellular proliferation over time at both doses, RANTES only at the Cmax dose, and SDF-1 p only at the ED50 dose. From the results of the AlamarBlue assay, we were also able to determine that the selected doses of chemokine supported cell viability. These encouraging results will direct further investigation into determining the optimal concentration of these chemokines for inducing chemotaxis in BM MSCs, and the proteins that individually or in combination will best aid in tissue regeneration.