Effect of Human Mesenchymal Stem Cells on Freund’s adjuvant-induced Rheumatoid Arthritis in Sprague Dawley Rats

Abstract

Introduction: Mesenchymal stem cells (MSC) therapy is a new approach to treat RA. Studies evaluating anti-inflammatory effects of MSCs per RA severity are scarce. Our primary objective was to evaluate anti-inflammatory effects, change in cytokine levels and cartilage regeneration of two different MSC preparations delivered through two different routes of administration in three RA stages: mild, moderate and severe. Methods: Human-derived umbilical cord tissue MSCs (hUCT-MSCs) and human bone marrow-derived MSCs (hBM-MSCs) delivered via intra-plantar and intravenous routes were tested in Freund's adjuvant-induced arthritis in rats. Arthritis severity was based on the arthritis score (<3=mild, 3=moderate and 4=severe). Assessments included changes in arthritis scoring, paw swelling, haematology parameters, biomarkers (TNFα and IL-10) and histopathology analysis. Results: MSC treatment significantly reduced arthritis scores in all treatment groups. IL-10 levels increased 30 days after treatment with (IP)hUCT-MSCs (P=0.0241), (IV)hUCT-MSCs (P=0.0095) and (IP)hBM-MSCs (P=0.0002). TNF-α levels reduced compared to positive control at 30 days: (IP)hUCT-MSCs (P=0.0060), (IV)hUCT-MSCs (P=0.0003), (IP)hBM-MSCs (P=0.0005), (IV)hBM-MSCs (P<0.0001) and continued through 30-60 days. Microscopic examination showed regenerative changes in animal joints treated with both intra-plantar or intravenous MSCs. Arthritis scores reduced in all RA severity groups while benefits (changes in IL-10 and TNF-α) were more pronounced in moderate and severe RA. Haematology parameters remained similar among all animal groups at baseline, 30 days and 60 days indicating safety of MSCs. Conclusion: Treatment with hUCT MSCs and hBM MSCs were safe, well-tolerated and effectively reduced joint inflammation, synovial cellularity and pro-inflammatory cytokine levels in CFA-induced RA rat model.