Anti-arthritic Effects of Undifferentiated and Chondrogenic Differentiated MSCs in MIA-induced Osteoarthritis in Wistar Rats: Involvement of Oxidative Stress and Immune Modulation.

Introduction: Osteoarthritis (OA) is a degenerative joint disease that can affect the many tissues of the joint. There are no officially recognized disease-modifying therapies for clinical use at this time probably due to a lack of complete comprehension of the pathogenesis of the disease. In recent years, emerging regenerative therapy and treatments with stem cells both undifferentiated and differentiated cells have gained much attention as they can efficiently promote tissue repair and regeneration.

Methods: To determine how bone marrow-derived mesenchymal stem cells (BM-MSCs) and chondrogenic differentiated MSCs (CD-MSCs) can treat OA in rats, OA was induced in Wistar rats by injecting three doses of 100 μL physiological saline containing 1 mg of MIA into rat ankle joint of the right hind leg for three consecutive days. Following the induction, the osteoarthritic rats were injected weekly with BM-MSCs or CD-MSCs at a dose of 1x106 cells/rat/dose for three weeks. In addition to morphological and histological investigations of the ankle, spectrophotometric, ELISA, and Western blot analyses were applied to detect various immunological and molecular parameters in serum and ankle.

Results: The results of the study showed that in osteoarthritic rats, BM-MSCs and CD-MSCs significantly reduced right hind paw circumference, total leucocyte count (TLC), differential leukocyte count (DLC) of neutrophils, monocytes, lymphocytes, and eosinophils, serum rheumatoid factor (RF), prostaglandin E2 (PGE2) and interleukin (IL-) 1β levels, while they elevated serum IL-10 level. Additionally, BM-MSCs and CD-MSCs markedly reduced lipid peroxides (LPO) levels while they elevated superoxide dismutase (SOD) and glutathione-S-transferase (GST) activities. The monocyte chemoattractant protein-1 (MCP-1) level was significantly downregulated in ankle joint articular tissues by treatment with BM-MSCs or CD-MSCs while nuclear factor erythroid 2-related factor 2 (Nrf2) was upregulated; CD-MSCs treatment was more effective.

Conclusion: According to these findings, it can be inferred that BM-MSCs and CD-MSCs have anti-arthritic potential in MIA-induced OA; CD-MSCs therapy is more effective than MSCs. The ameliorative anti-arthritic effects may be mediated by suppressing inflammation and oxidative stress through the downregulation of MCP-1 and upregulation of Nrf2. Based on the obtained results, BM-MSCs and CD-MSCs therapies are promising new options that can be associated with other clinical treatments to improve cartilage regeneration and joint healing. However, more preclinical and clinical research is required to assess the benefits and safety of treating osteoarthritic patients with BM-MSCs and CD-MSCs.