Human umbilical cord mesenchymal stem cells as treatment of adjuvant rheumatoid arthritis in a rat model

Figure 4 Photomicrograph of rat from negative control group (A), positive control group (B), positive control group (C), methotrexate group (D), CD34 group (E) and mesenchymal group (F). A: Negative control group showed synovial tissue with delicate collagen fibers (arrows) (Masson’s trichrome, × 400); B: Positive control (PC) group showed vascular edema and vacuoles (arrows) within vessels (V) of the synovial tissue (Masson’s trichrome × 200); C: PC group showed extensive fibrosis (arrows) completely obliterating the joint cavity (Masson’s trichrome, × 200); D: Methotrexate group showed moderate increase in collagen fibers (arrows) of the synovial tissue (Masson’s trichrome, × 200); E: CD34 group showed mild increase in collagen fibers (arrows) of the synovial tissue (Masson’s trichrome, × 200); F: Mesenchymal group showed mild increase in collagen fibers (arrows) of the synovial tissue (Masson’s trichrome, × 200).