Evaluation of Proliferation and Osteogenic Differentiation of Human Umbilical Cord-Derived Mesenchymal Stem Cells in Porous Scaffolds.

Abstract

Human umbilical cord-derived mesenchymal stem cells (UCMSCs) are multiple potential stem cells that can differentiate into various kinds of functional cells, including adipocytes, osteoblasts, and chondroblasts. Thus, UCMSCs have recently been used in both stem cell therapy and tissue engineering applications to produce various functional tissues. This study aimed to evaluate the proliferation and differentiation of UCMSCs on porous scaffolds. UCMSCs were established in a previous study and kept in liquid nitrogen. They were thawed and expanded in vitro to yield enough cells for further experiments. The cells were characterized as having MSC phenotype. They were seeded onto culture medium-treated porous scaffolds or on non-treated porous scaffolds at different densities of UCMSCs (105, 2.1×105, and 5×105 cells/0.005g scaffold). The existence of UCMSCs on the scaffold was evaluated by nucleic staining using Hoechst 33342 dye, while cell proliferation on the scaffold was determined by MTT assay. Osteogenic differentiation was evaluated by changes in cellular morphology, accumulation of extracellular calcium, and expression of osteoblast-specific genes (including runx2, osteopontin (OPN), and osteocalcin (OCN)). The data showed that UCMSCs could attach, proliferate, and differentiate on both treated and non-treated scaffolds but were better on the treated scaffold. At a cell density of 105 cells/0.005g scaffold, the adherent and proliferative abilities of UCMSCs were higher than that of the other densities after 14days of culture (p<0.05). Adherent UCMSCs on the scaffold could be induced into osteoblasts in the osteogenic medium after 21days of induction. These cells accumulated calcium in the extracellular matrix that was positive with Alizarin Red staining. They also expressed some genes related to osteoblasts, including runx2, OPN, and OCN. UCMSCs could adhere, proliferate, and differentiate into osteoblasts on porous scaffolds. Therefore, porous scaffolds (such as Variotis) may be suitable scaffolds for producing bone tissue in combination with UCMSCs.