Fig. 2.

Effect of hypoxia and cartilage oligomeric matrix protein (COMP) on the levels of mitochondrial matrix and extra-mitochondrial matrix superoxide detected by MitoSOX and dihydroethidium (DHE), respectively. A: level of superoxide-specific metabolites of MitoSOX and DHE detected by HPLC in bovine pulmonary artery (BPA) cultured under 21 or 3% O₂ for 48 h in the absence or presence of COMP. **P < 0.01 (two-way ANOVA with Sidak correction, n = 10; A). B: COMP protein level deceased by COMP siRNA (*P < 0.05, paired t test, n = 5; B). C: level of MitoSOX (n = 14) and DHE (n = 8) superoxide detected by HPLC in BPA treated with COMP siRNA or scramble siRNA (*P < 0.05, **P < 0.01 for COMP siRNA versus scramble siRNA, paired t test).