Follistatin Alleviates Synovitis and Articular Cartilage Degeneration Induced by Carrageenan

Figure 2

Histological analyses of synovial inflammation induced by carrageenan. (a, b) H&E staining of sagittal sections of mice knee joints at day 3 (a) and day 14 (b) after carrageenan injection. Boxed areas in the left panels are magnified and presented in the right panels. CA: carrageenan group; CA + FLT: carrageenan + follistatin group; Con: control group. Magnification: left ×40, right ×100. (c) Semiquantitative analyses of synovial inflammation. The severity of synovial inflammation was evaluated according to the synovitis scoring system (Synovitis Score (Blom et al., osteoarthritis and cartilage, 2004 [20])). The synovitis scores are indicated as the total of four different areas in the knee joint as denoted in upper panel. . (d, e) Immunohistochemical analyses of macrophage infiltration into synovial membrane at day 3 (d) and at day 14 (e) after carrageenan injection. Sagittal sections of mice knee joints were stained with F4/80 antibody. Sections were counterstained with hematoxylin. Boxed areas in the left panels are magnified and presented in the right panels. CA: carrageenan group; CA + FLT: carrageenan + follistatin group; Con: control group. Magnification: left ×40, right ×100. (f) Semiquantitative analyses of the degree of F4/80-positive macrophage infiltration into synovial membrane (F4/80 Score (Willis et al., JOI, 2012 [22])). The scores were indicated as the total of four different areas of the synovial membrane (superficial layer (boxed by red) and deep layer (boxed by blue) of suprapatellar or infrapatellar region) as described in the upper panel .

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