Abstract:

BACKGROUND: The occurrence and development of rheumatoid arthritis were strongly associated with unbalance proliferation and apoptosis of synovial cells and lymphocytes. Some synovial cell apoptosis was abnormal.
OBJECTIVE: To observe effects of heterogenic double umbilical cord blood stem cell transplantation on Bcl-2 and Bax expression in mice with type Ⅱ collagen-induced arthritis.
METHODS: C57BL/6(H-2b) mice were induced with Freund’s complete adjuvant and type Ⅱ collagen to establish mouse models of type Ⅱ collagen-induced arthritis. At 2 days after secondary immunity incubation, mice were injected with saline via tail vein in the model and normal control groups. Umbilical cord blood hemopoietic stem cells were injected into mouse tail vein in the UBSCs transplantation groups (single dose: 2×106/50 g; double dose: 1×106/50 g each, totally 2×106/50 g). Mice were intragastrically administrated methotrexate in the methotrexate positive control group, 0.017 5 g/kg once, once every 5 days, totally six times.
RESULTS AND CONCLUSION: Joint tissue below knee and elbow was obtained at 42 days following transplantation. Histopathology displayed that smooth and glossy articular surface, no inflammatory cell infiltration in the synovial layer and normal chondrocytes in the normal control group. Hyperplasia, a lot of inflammatory cell infiltration and damaged cartilage surface were visible in the model group. Slight hyperplasia and a little inflammatory cell infiltration were detectable in the methotrexate positive control group and single UBSCs transplantation group. Double UBSCs transplantation group exhibited smooth and glossy articular cartilage surface, no damage, a little inflammatory cell infiltration. Immunohistochemistry demonstrated that Bcl-2 and Bax expression was lower in the double UBSCs transplantation group compared with single UBSCs transplantation group (P < 0.05). Compared with normal control group, no significant difference was detected (P > 0.05). Results suggest that double umbilical cord blood stem cells can induce synovial cell apoptosis in mice with type Ⅱ collagen-induced arthritis in a certain number and action time, and protect synovial membrane against damage.