MMP9 and pulmonary arterial hypertension: As presented in Fig. 5D, the ratio of MMP-9/TIMP-1 and MMP-2/TIMP-2 was 1.57-/1.60-fold over control in MCT-treated rats (P < 0.05); MS-275 treatment decreased the ratio of MMP-9/TIMP-1 and MMP-2/TIMP-2 in MCT-treated PAH rats to 1.20-/1.30-fold over control (P < 0.05 versus MCT-treated group), and administration of miR-34a agomiR reduced the ratio of MMP-9/TIMP-1 and MMP-2/TIMP-2 in MCT-treated rats to 1.22-/1.25-fold over control (P < 0.05 versus MCT group).