MRC1 and arthritic joint disease: The expression of genes related to macrophage infiltration (F4/80) and the ratio of mRNA expression of genes involved in macrophage M1 polarization state (CD11c/CD206 and CD11c/CD209e) were significantly elevated in arthritic mice compared to control lean, suggesting that arthritis induces the infiltration and presence of M1 macrophages in adipose tissue (Figures 2C–E).