Quantitative Analyses of Cells using Photoshop after the H&E Staining of the Synovia of Osteoarthritis and Rheumatoid Arthritis Patients

Abstract

Synovium is the soft tissue that lines the non-cartilaginous surfaces within joints. It has been reported that synovial cells are activated during the pathogenesis of rheumatoid arthritis. In this study, we quantitate and compare the cellular composition of synovia derived from individuals with non-inflammatory osteoarthritis (OA) and those with inflammatory rheumatoid arthritis (RA). Synovia from OA (n=8) and RA (n=5) patients were used for hematoxylin and eosin (H&E) staining. A light microscopic examination has shown that RA synovia were morphologically thickened and hypertrophied as compared to OA synovia. We also performed an immunohistochemistry (IHC) analysis to classify cell types in the synovia using CD68, CD90, or PGP9.5 markers. As a result, we obtained quantitative data regarding the cell populations, which are macrophages in the lining layer and FLSs in the subintimal layer of the synovium. Further Photoshop analyses of the H&E images could allow the counting of the number and layer of the cells in the synovium. The number and layers of the macrophage cells were increased in the lining layer of the RA synovia as compared to the OA synovia. FLS cells also were increased in the subintimal layer of RA synovia. Therefore, quantification of the H&E stained images via Photoshop is a possible analysis protocol for synovium study. This quantitation also supports the idea that the increases in cell number and cell activation are important processes for RA pathogenesis.