Regulation of the secretion of immunoregulatory factors of mesenchymal stem cells (MSCs) by collagen-based scaffolds during chondrogenesis.

In the latest decade, mesenchymal stem cells (MSCs) have wildly considered as a source of seeded cells in tissue engineering, not only because of its multi-differentiation potentials, but also due to its immunoregulation ability. The main immunoregulatory features of MSCs could be divided into low self-immunogenicity and secretion of soluble factors. In this study, we explored how scaffold structures modulated the secretion of soluble immunoregulatory factors in MSCs under an allogeneic cartilage tissue engineering background. MSCs were seeded in four different collagen-based scaffolds. Their proliferation, differentiation, and secretion of various soluble factors associated with the immunosuppressive effects were evaluated. In this study, qRT-PCR, ELISA and immunoregulation results showed a great variability of the factor secretion by MSCs seeded in scaffolds with different structures. Compared with two-dimensional (2D) monolayer culture condition, three-dimensional (3D) groups (hydrogels and sponge) could effectively promote the mRNA expression and the protein production of soluble immune-related factors. Also, the supernatants collected from 3D groups obviously showed inhibition on allogeneic lymphocyte activating. These results suggested that scaffold structures might modulate MSCs' secretion of soluble immunoregulatory factors, and our study might enlighten the scaffold designs for desired tissue regeneration to control the host immune rejection through immune-regulation reaction.