2.7. Blood Sampling
OXIDATIVE STRESS, LYSIS
Venous blood samples were collected into heparin and ethylenediaminetetraacetic acid (EDTA) vacutainer tubes and centrifuged at room temperature. The plasma layer and erythrocytes were collected, aliquoted and stored at −80 °C until measurement of creatine kinase (CK), cartilage oligomeric matrix protein (COMP), oxidative stress, antioxidant capacity and cytokine concentrations.For isolation of peripheral blood mononuclear cells (PBMC), the buffy coat interface containing mononuclear cells following centrifugation was collected and washed with Dulbecco’s phosphate-buffered saline (DPBS). Following incubation in erythrocyte lysis buffer (Sigma; Cat. No. R7757, St. Louis, MO, USA), cells were washed and suspended in DPBS for subsequent cell staining.