Chondrogenesis of human mesenchymal stem cells encapsulated in a hydrogel construct: Neocartilage formation in animal models as both mice and rabbits

In this study, in vivo studies, both nude mouse and rabbit cartilage defect, were tested for chondrogenesis using stem cells (SCs) using growth factor. Specifically, human mesenchymal stem cells (hMSCs) were embedded in a hydrogel scaffold, which was coencapsulated with transforming growth factor-β3 (TGF-β3). The specific extracellular matrices (ECMs) released from hMSCs transplanted into the animal were assessed via glycosaminoglycan (GAG)/DNA content, RT-PCR, real time-QPCR, immunohistochemical (IHC), and Safranin-O staining and were observed up to 7 weeks after injection. By detection of ECMs the GAG content per cell remained constant for all formulations, indicating that the dramatic increase in cell number for samples with TGF-β3 was accompanied by the maintenance of the cell phenotypes. The histological and IHC staining of the newly repaired tissues observed after treatment with TGF-β3 mixed with hMSCs evidenced hyaline cartilage-like characteristics. Moreover, the results observed with the animal model (rabbit) treated with hMSCs embedded in the growth factor-containing hydrogel indicate that the implantation of mixed cells with TGF-β3 may constitute a clinically efficient method for the regeneration of hyaline articular cartilage.