Figure 7. Knockdown of RIPK1 protects chondrocytes against apoptosis in vitro and in vivo. (A, B) Transferase dUTP nick-end labeling (TUNEL)-stained mouse chondrocytes treated as above; scale bar = 200 μm. (C, D) TUNEL-stained paraffin-wax sections of articular cartilage. Red fluorescence, apoptotic cells; blue fluorescence, nuclei (n = 10). Scale bar = 400 μm. The experiments were repeated three times independently. Columns represent means ± SD. ***p < 0.001, ****p < 0.001.