Figure 4. CLU expression in cartilage and chondrocyte cultures of fractured and OA patients. (A) Representative images of CLU immunohistochemistry on femoral cartilage of fractured and OA patients. (B) Percentage of CLU+ cells and (C) extracellular CLU secretion in femoral cartilage of fractured (n=30 donors; yellow bars) and OA patients (n=30 donors; green bars). Student’s t-test: **P < 0.001 and Mann-Whitney’s U-test: P < 0.0001, respectively. (D) Representative images and semi-quantitative evaluation of CLU immunocytochemistry on cytospinned HACs from fractured and OA patients. Data are expressed as mean values ± SEM of three independent experiments (each using pooled samples from n=3 fractured and n=3 OA donors) performed in triplicate. (E) CLU mRNA levels by Real-Time PCR and (F) representative blot and densitometric analysis of CLU protein in cultured HACs from fractured and OA cartilage of individual donors (n=10 fractured and n=10 OA patients). Experiments were performed in triplicate. Data are expressed as mean values ± SEM. Abbreviations: A.U, arbitrary units; F-HACs, fractured patient human articular chondrocytes; OA-HACs, OA-Human articular chondrocytes; psCLU, CLU precursor protein. Student’s t-test: *P < 0.01, ***P < 0.0001.