Hematoxylin-Eosin (H&E) staining and Histopathological examination
After decalcification of mice joints in 10% EDTA, together with human synovial tissues, they were embedded in paraffin, and stained with H&E staining for light microscopy. Histopathological quantification was made by investigators in a blinded manner from images of three fields representing the distal interphalangeal joint, the proximal interphalangeal joint, and joints in the carpal region and averaged over all joints in one limb of each animal. Inflammation was scored 0 to 5 according to the following criteria: 0, normal; 1, minimal inflammatory infiltration; 2, mild infiltration; 3, moderate infiltration with moderate edema; 4, marked infiltration with marked edema; and 5, severe infiltration with edema. Hyperplasia was defined as synovial tissue intimately invading bone and/or cartilage and was scored 0 to 3 as follows: 0, none; 1, minimal; 2, moderate; 3, severe. Bone degradation was scored using the following 0 to 3 scale: 0, no bone erosion; 1, mild surface erosion; 2, moderate surface erosion; and 3, strong surface erosion. Sections were also stained by Safranin O/ Fast green kit (Solarbio) for detection of cartilage damage (0: no changes; 1: erosion in part of the cartilage surface; 2: erosion of the cartilage surface and cartilage destruction; 3: cartilage erosion and destruction, combined with cartilage covered by connective tissue; 4: Cartilage and cartilage covered by connective tissue are corroded and damaged severely).