ABSTRACT
Objective The aim of this study was to analyze the distribution characteristics of CD163+ macrophages in peripheral blood and synovium of patients with osteoarthritis (OA)，and investigate the correlation of CD163+ macrophages, intracellular tumour necrosis factor(TNF-α), interleukin-10 (IL-10) expression with the disease duration, inflammation level and body mass index (BMI). Methods The percentages of CD163+ macrophages in synovium and peripheral blood and their intracellular levels of TNF-α and IL-10 were detected by flow cytometry. Meanwhile, immunofluorescence was uesed to observe the distribution of CD163+ macrophages in synovial tissue of patients with OA or fracture. Results (1) There were significant differences in the percentage of CD163+ macrophages in synovial and peripheral blood between OA and fracture patients(all P<0.05). (2) The expression of TNF-α in CD163+ macrophages of synovium and blood of OA patients with disease duration below 10 years was significantly higher than that of patients with OA disease duration above 10 years (all P<0.05) . The expression of IL-10 was significantly lower than that of patients with OA disease duration above 10 years (all P<0.05). (3) C-reactive protein (CRP) was positively correlated with BMI in patients with OA disease duration below 10 years (r=0.680， P<0.001), while showed no correlation with BMI in patients with OA duration above 10 years(r=0.084， P=0.187). (4) Immunofluorescence confocal microscopy showed a large number of CD163+ macrophages invaded around the synovial vessel of patients with OA. Conclusion The distribution of CD163+ macrophages in synovium and peripheral blood of OA patients with different course of disease was different, and showed differentiated cell subtypes.