Fig. 3.

Loss of Enpp1 aggravates cell apoptosis in articular cartilage: A TUNEL staining of WT and Enpp1^−/− articular cartilage (TUNEL-positive chondrocyte, red; DAPI, blue; scale bar: 100 µm, n ≥ 3). B The percentage of TUNEL-positive chondrocytes in WT and Enpp1^−/− knee joints (WT groups = 10.33% ± 2.08% and Enpp1^−/− groups = 76.67% ± 3.79%, p < 0.0001, n ≥ 3). Enpp1, ectonucleotide pyrophosphatase/phosphodiesterase 1; TUNEL, TdT-mediated dUTP-biotin nick end labeling; WT, wild type; DAPI, 4′,6-diamidino-2-phenylindole