Figure 6. EC-Exos decreased the ability of chondrocytes to resist oxidative stress and increased the number of apoptotic chondrocytes in the OA mouse model. (A) Immunohistochemical staining for p21 expression in the knee-joint samples. (B) Immunohistochemical staining for HO-1 expression in the knee-joint samples. (C) Immunofluorescence staining for C-caspase3 expression in the knee-joint specimens from three groups of mice.