Human umbilical cord mesenchymal stem cells improve the immune-associated inflammatory and prothrombotic state in collagen type-â ¡-induced arthritic rats.

Human umbilical cord mesenchymal stem cells (hUC­MSCs) hold great potential in the search for therapies to treat refractory diseases, including rheumatoid arthritis (RA), due to their potential regenerative ability and extensive source. However, the role of hUC­MSCs in vivo and the repair mechanisms for RA remain to be fully elucidated. The present study aimed to determine whether hUC­MSCs exert immunomodulatory effects and have anti­inflammatory capabilities in the treatment of embolisms. Following the transplantation of hUC­MSCs into collagen type Ⅱ­induced arthritic (CIA) model rats, magnetic resonance imaging (MRI) in vivo was performed, and the levels of interleukin (IL)­1, IL­17, tumor necrosis factor (TNF)­α, vascular endothelial growth factor (VEGF), tissue factor (TF), CD4+CD25+ T cells (Treg) and antithrombin (AT) were measured. Bromodeoxyuridine staining was performed for histopathological examinations. As revealed by immunofluorescence and MRI experiments, the injected hUC­MSCs preferentially migrated to the inflammatory joint sites of the rats. The Treg cell percentage and AT levels in the hUC­MSC­treated group were markedly increased, whereas the levels of IL­1, IL­17, TNF­α, VEGF and TF were decreased compared with those in the CIA model group. The values determined for these parameters in the hUC­MSC­treated group returned to approximately the identical values as those of the control group on day 35 post­therapy. Superparamagnetic iron oxide nanoparticles (SPIONs) may serve as an effective, non­invasive method for tracking transplanted cells in vivo. The present study provided direct evidence that hUC­MSCs in the CIA rat model migrated to the inflammatory joint sites, effectively promoting recovery from collagen type II damage and thereby improving the immune­associated prothrombotic state.