Figure 4

Immunohistochemistry and double staining combining in situ hybridization. A, Representative histology of RA and OA by immunohistochemistry of IL-17. RA synovium with high expression level of miR-146a/b, miR-150 and miR-155 demonstrated amount IL-17 positive cells in hyperplasia synovium while OA synovium had few IL-17 positive cells in the fibrous tissue. Original magnification 100×. Bar indicates 100 μm. B, Double staining for the in situ hybridization and immunohistochemistry of rheumatoid arthritis (RA) and osteoarthritis synovial tissue. In situ hybridization (ISH) for mature microRNA146-a (miR-146a) and immunohistochemistry with IL-17 antibodies were performed on synovial tissue specimens obtained from patient RA7 and OA3. Mature miR-146a was expressed in the cells of the superficial and sublining layers, thus including IL-17 positive cells. The arrows in the merged images indicate the cells expressing miR-146a and IL-17 antibody. Staining of the tissue sections with 4, 6-diamidino-2- phenylindole (DAPI) is shown at the right. (Original magnification X200).